DataMuseum.dk

Presents historical artifacts from the history of:

DKUUG/EUUG Conference tapes

This is an automatic "excavation" of a thematic subset of
artifacts from Datamuseum.dk's BitArchive.

See our Wiki for more about DKUUG/EUUG Conference tapes

Excavated with: AutoArchaeologist - Free & Open Source Software.


top - metrics - download
Index: T U

⟦f3953c84c⟧ TextFile

    Length: 235053 (0x3962d)
    Types: TextFile
    Notes: Uncompressed file

Derivation

└─⟦4f9d7c866⟧ Bits:30007245 EUUGD6: Sikkerheds distributionen
    └─⟦711eaac9c⟧ »./papers/Routing_security/visa-89.ps.Z« 
        └─⟦this⟧ 

TextFile

%!PS-Adobe-2.0
%%Creator: dvips 5.47 Copyright 1986-91 Radical Eye Software
%%Title: vpaper.dvi
%%Pages: 28 1
%%BoundingBox: 0 0 612 792
%%EndComments
%%BeginProcSet: tex.pro
/TeXDict 200 dict def TeXDict begin /N /def load def /B{bind def}N /S /exch
load def /X{S N}B /TR /translate load N /isls false N /vsize 10 N /@rigin{
isls{[0 1 -1 0 0 0]concat}if 72 Resolution div 72 VResolution div neg scale
Resolution VResolution vsize neg mul TR matrix currentmatrix dup dup 4 get
round 4 exch put dup dup 5 get round 5 exch put setmatrix}N /@letter{/vsize 10
N}B /@landscape{/isls true N /vsize -1 N}B /@a4{/vsize 10.6929133858 N}B /@a3{
/vsize 15.5531 N}B /@ledger{/vsize 16 N}B /@legal{/vsize 13 N}B /@manualfeed{
statusdict /manualfeed true put}B /@copies{/#copies X}B /FMat[1 0 0 -1 0 0]N
/FBB[0 0 0 0]N /nn 0 N /IE 0 N /ctr 0 N /df-tail{/nn 8 dict N nn begin
/FontType 3 N /FontMatrix fntrx N /FontBBox FBB N string /base X array
/BitMaps X /BuildChar{CharBuilder}N /Encoding IE N end dup{/foo setfont}2
array copy cvx N load 0 nn put /ctr 0 N[}B /df{/sf 1 N /fntrx FMat N df-tail}
B /dfs{div /sf X /fntrx[sf 0 0 sf neg 0 0]N df-tail}B /E{pop nn dup definefont
setfont}B /ch-width{ch-data dup length 5 sub get}B /ch-height{ch-data dup
length 4 sub get}B /ch-xoff{128 ch-data dup length 3 sub get sub}B /ch-yoff{
ch-data dup length 2 sub get 127 sub}B /ch-dx{ch-data dup length 1 sub get}B
/ch-image{ch-data dup type /stringtype ne{ctr get /ctr ctr 1 add N}if}B /id 0
N /rw 0 N /rc 0 N /gp 0 N /cp 0 N /G 0 N /sf 0 N /CharBuilder{save 3 1 roll S
dup /base get 2 index get S /BitMaps get S get /ch-data X pop /ctr 0 N ch-dx 0
ch-xoff ch-yoff ch-height sub ch-xoff ch-width add ch-yoff setcachedevice
ch-width ch-height true[1 0 0 -1 -.1 ch-xoff sub ch-yoff .1 add]{ch-image}
imagemask restore}B /D{/cc X dup type /stringtype ne{]}if nn /base get cc ctr
put nn /BitMaps get S ctr S sf 1 ne{dup dup length 1 sub dup 2 index S get sf
div put}if put /ctr ctr 1 add N}B /I{cc 1 add D}B /bop{userdict /bop-hook
known{bop-hook}if /SI save N @rigin 0 0 moveto}N /eop{clear SI restore
showpage userdict /eop-hook known{eop-hook}if}N /@start{userdict /start-hook
known{start-hook}if /VResolution X /Resolution X 1000 div /DVImag X /IE 256
array N 0 1 255{IE S 1 string dup 0 3 index put cvn put}for}N /p /show load N
/RMat[1 0 0 -1 0 0]N /BDot 260 string N /rulex 0 N /ruley 0 N /v{/ruley X
/rulex X V}B /V statusdict begin /product where{pop product dup length 7 ge{0
7 getinterval(Display)eq}{pop false}ifelse}{false}ifelse end{{gsave TR -.1 -.1
TR 1 1 scale rulex ruley false RMat{BDot}imagemask grestore}}{{gsave TR -.1
-.1 TR rulex ruley scale 1 1 false RMat{BDot}imagemask grestore}}ifelse B /a{
moveto}B /delta 0 N /tail{dup /delta X 0 rmoveto}B /M{S p delta add tail}B /b{
S p tail}B /c{-4 M}B /d{-3 M}B /e{-2 M}B /f{-1 M}B /g{0 M}B /h{1 M}B /i{2 M}B
/j{3 M}B /k{4 M}B /w{0 rmoveto}B /l{p -4 w}B /m{p -3 w}B /n{p -2 w}B /o{p -1 w
}B /q{p 1 w}B /r{p 2 w}B /s{p 3 w}B /t{p 4 w}B /x{0 S rmoveto}B /y{3 2 roll p
a}B /bos{/SS save N}B /eos{clear SS restore}B end
%%EndProcSet
%%BeginProcSet: special.pro
TeXDict begin /SDict 200 dict N SDict begin /@SpecialDefaults{/hs 612 N /vs
792 N /ho 0 N /vo 0 N /hsc 1 N /vsc 1 N /ang 0 N /CLIP false N /BBcalc false N
/p 3 def}B /@scaleunit 100 N /@hscale{@scaleunit div /hsc X}B /@vscale{
@scaleunit div /vsc X}B /@hsize{/hs X /CLIP true N}B /@vsize{/vs X /CLIP true
N}B /@hoffset{/ho X}B /@voffset{/vo X}B /@angle{/ang X}B /@rwi{10 div /rwi X}
B /@llx{/llx X}B /@lly{/lly X}B /@urx{/urx X}B /@ury{/ury X /BBcalc true N}B
/magscale true def end /@MacSetUp{userdict /md known{userdict /md get type
/dicttype eq{md begin /letter{}N /note{}N /legal{}N /od{txpose 1 0 mtx
defaultmatrix dtransform S atan/pa X newpath clippath mark{transform{
itransform moveto}}{transform{itransform lineto}}{6 -2 roll transform 6 -2
roll transform 6 -2 roll transform{itransform 6 2 roll itransform 6 2 roll
itransform 6 2 roll curveto}}{{closepath}}pathforall newpath counttomark array
astore /gc xdf pop ct 39 0 put 10 fz 0 fs 2 F/|______Courier fnt invertflag{
PaintBlack}if}N /txpose{pxs pys scale ppr aload pop por{noflips{pop S neg S TR
pop 1 -1 scale}if xflip yflip and{pop S neg S TR 180 rotate 1 -1 scale ppr 3
get ppr 1 get neg sub neg ppr 2 get ppr 0 get neg sub neg TR}if xflip yflip
not and{pop S neg S TR pop 180 rotate ppr 3 get ppr 1 get neg sub neg 0 TR}if
yflip xflip not and{ppr 1 get neg ppr 0 get neg TR}if}{noflips{TR pop pop 270
rotate 1 -1 scale}if xflip yflip and{TR pop pop 90 rotate 1 -1 scale ppr 3 get
ppr 1 get neg sub neg ppr 2 get ppr 0 get neg sub neg TR}if xflip yflip not
and{TR pop pop 90 rotate ppr 3 get ppr 1 get neg sub neg 0 TR}if yflip xflip
not and{TR pop pop 270 rotate ppr 2 get ppr 0 get neg sub neg 0 S TR}if}
ifelse scaleby96{ppr aload pop 4 -1 roll add 2 div 3 1 roll add 2 div 2 copy
TR .96 dup scale neg S neg S TR}if}N /cp{pop pop showpage pm restore}N end}if}
if}N /normalscale{Resolution 72 div VResolution 72 div neg scale magscale{
DVImag dup scale}if}N /psfts{S 65536 div N}N /startTexFig{/psf$SavedState save
N userdict maxlength dict begin /magscale false def normalscale currentpoint
TR /psf$ury psfts /psf$urx psfts /psf$lly psfts /psf$llx psfts /psf$y psfts
/psf$x psfts currentpoint /psf$cy X /psf$cx X /psf$sx psf$x psf$urx psf$llx
sub div N /psf$sy psf$y psf$ury psf$lly sub div N psf$sx psf$sy scale psf$cx
psf$sx div psf$llx sub psf$cy psf$sy div psf$ury sub TR /showpage{}N
/erasepage{}N /copypage{}N /p 3 def @MacSetUp}N /doclip{psf$llx psf$lly
psf$urx psf$ury currentpoint 6 2 roll newpath 4 copy 4 2 roll moveto 6 -1 roll
S lineto S lineto S lineto closepath clip newpath moveto}N /endTexFig{end
psf$SavedState restore}N /@beginspecial{SDict begin /SpecialSave save N gsave
normalscale currentpoint TR @SpecialDefaults}N /@setspecial{CLIP{newpath 0 0
moveto hs 0 rlineto 0 vs rlineto hs neg 0 rlineto closepath clip}if ho vo TR
hsc vsc scale ang rotate BBcalc{rwi urx llx sub div dup scale llx neg lly neg
TR}if /showpage{}N /erasepage{}N /copypage{}N newpath}N /@endspecial{grestore
clear SpecialSave restore end}N /@defspecial{SDict begin}N /@fedspecial{end}B
/li{lineto}B /rl{rlineto}B /rc{rcurveto}B /np{/SaveX currentpoint /SaveY X N 1
setlinecap newpath}N /st{stroke SaveX SaveY moveto}N /fil{fill SaveX SaveY
moveto}N /ellipse{/endangle X /startangle X /yrad X /xrad X /savematrix matrix
currentmatrix N TR xrad yrad scale 0 0 1 startangle endangle arc savematrix
setmatrix}N end
%%EndProcSet
TeXDict begin 1000 300 300 @start /Fa 4 84 df<00001000000030000000700000007000
0000F8000000B8000001380000023800000238000004380000043800000838000010380000103C
0000201C0000201C00007FFC0000801C0000801C0001001C0003001C0002001C0004001E000400
0E001C001E00FF00FFC01A1A7F991D>65 D<0007E040003C18C000E005C001C003C00380018007
0001800E0001801C0001803C000100380001007800000078000000F0000000F0000000F0000000
F0000000F0000400F0000400F0000400F00008007000100030001000380060001C008000070300
0001FC00001A1A7E991B>67 D<01FF8FFC003801C0003801C0003801C000700380007003800070
03800070038000E0070000E0070000E0070000E0070001FFFE0001C00E0001C00E0001C00E0003
801C0003801C0003801C0003801C00070038000700380007003800070038000E007000FFE7FF00
1E1A7E9920>72 D<001F080060D800803801003803001006001006001006001006000007000007
C00003FC0001FF00007F800007C00001C00001C00000C02000C02000C060018060018060030070
0600CC0C0083F000151A7E9917>83 D E /Fb 6 117 df<00FC000303000C01801800C03000C0
6000C06000C0C000C0C000C0C000C0C00180C00180C00300600600600C003838000FC00012117D
9017>79 D<0780184030C060006000C000C000C000402060C01F000B0B7E8A0E>99
D<007800180018003000300030073018E0306060606060C0C0C0C0C0C841C862D03C700D117E90
10>I<73C09C209860980018003000300030003000600060000B0B7E8A0E>114
D<0F001080218020003E001F0001808080C00083007C00090B7D8A0F>I<08181818FF30303030
606062646438080F7E8E0C>I E /Fc 12 122 df<FF80FF80FF0009037D880E>45
D<03CC0E2E181C381C301C701CE038E038E038E038C072C072C07260F261341E180F107C8F14>
97 D<01E006181C08380870087010FFE0E000E000E000E000E0086010602030C01F000D107C8F
12>101 D<00F300038B800607000E07000C07001C0700380E00380E00380E00380E00301C0030
1C00301C00183C0018780007B800003800003800007000607000E0E000C1C0007F000011177E8F
12>103 D<030706000000000000384C4E8E9C9C1C3838707272E2E4643808197C980C>105
D<307C005986009E07009E07009C07009C0700380E00380E00380E00381C00701C80701C807038
80703900E01900600E0011107C8F16>110 D<01F006180C0C180E300E700E600EE00EE00EE00C
E01CE018E030606030C01F000F107C8F14>I<03E004300830187018601C001F801FC00FE000E0
0060E060E06080C041803E000C107D8F10>115 D<06000E000E000E000E001C001C00FFC01C00
38003800380038007000700070007000E100E100E100E200640038000A177C960D>I<38184C1C
4E1C8E0C9C0C9C0C1C08380838083808701070107020304018C00F000E107C8F12>118
D<380C304C0E384E1C388E1C189C1C189C1C181C38103838103838103838107070207070207070
4030704018B8800F0F0015107C8F19>I<38064C074E0E8E0E9C0E9C0E1C1C381C381C381C7038
70387038307838F00F700070006060E0E1C0C18047003C0010177C8F13>121
D E /Fd 1 64 df<1FF0303C701EF81FF81FF81F703E007C00F000C00180018003000300030003
00000000000000000007800FC00FC00FC00FC00780101A7E9915>63 D E
/Fe 16 121 df<07FE1FF800E0038000E0038000E0038000E0038001C0070001C0070001C00700
01C0070003800E0003800E0003FFFE0003800E0007001C0007001C0007001C0007001C000E0038
000E0038000E0038000E0038001C007000FF83FE001D177F961D>72 D<07FE00E000E000E000E0
01C001C001C001C0038003800380038007000700070007000E000E000E000E001C00FFC00F177E
960F>I<07FE03F800E001C000E0010000E0020000E0080001C0100001C0200001C0800001C100
0003830000038F00000393800003A380000781C0000701C0000700E0000700E0000E0070000E00
70000E0038000E0038001C003C00FF80FF001D177F961E>75 D<001FC000707001C01803001C06
000C0E000E1C000E18000E38000E30000E70000E70000E70000E70001CE0001C60003870003870
00707000E03801C01803800E0E0003F00017177F961B>79 D<07FFF800E00E00E00700E00700E0
0701C00701C00701C00701C00E03801C03807003FFC00380000700000700000700000700000E00
000E00000E00000E00001C0000FF800018177F9616>I<07FFF00000E01C0000E0060000E00700
00E0070001C0070001C0070001C0070001C00E0003801C000380700003FF80000380E000070070
000700380007003800070038000E0070000E0070000E0070800E0070801C003100FF801E001917
7F961B>82 D<FF807F1C00181C00101C00301C00200E00400E00400E00800E01000E01000E0200
0E04000F040007080007100007100007200007600007400007800003800003000002000018177E
9615>86 D<07C00C20107020706000C000C000C00080008000C010C02060C03F000C0E7E8D0F>
99 D<003E000C000C000C000C0018001800180018073018F0307060706060C060C060C06080C0
80C480C4C1C446C838700F177E9612>I<07C01C20301060106020FFC0C000C000C000C000C010
402060C01F000C0E7E8D10>I<0300038003000000000000000000000000001C00240046004600
8C000C0018001800180031003100320032001C0009177F960C>105 D<383C0044C60047020046
02008E06000C06000C06000C0C00180C00180C40181840181880300880300F00120E7F8D15>
110 D<38F04518463846308C000C000C000C001800180018001800300030000D0E7F8D10>114
D<07C00C201870187038001E000FC003E000606060E060C0C0C1803F000C0E7E8D10>I<030003
000600060006000600FFC00C000C000C001800180018001800300030803080310031001E000A14
7F930D>I<0F1F0011A18020C38020C300418000018000018000018000030000030200C30200E7
0400C5080078F000110E7F8D14>120 D E /Ff 38 122 df<70F8F8F87005057C840D>58
D<70F8FCFC74040404080810102040060E7C840D>I<000002000000060000000E0000000E0000
001E0000001F0000002F0000002F0000004F0000008F0000008F0000010F0000010F0000020F00
00040F0000040F0000080F8000080780001007800020078000200780007FFF8000400780008007
80018007800100078002000780020007C0040003C00C0003C01E0007C0FF807FFC1E207E9F22>
65 D<0000FE0200078186001C004C0038003C0060003C00C0001C01C000180380001807000018
0F0000181E0000101E0000103C0000003C00000078000000780000007800000078000000F00000
00F0000000F0000000F0000000F000008070000080700000807000010038000100380002001800
04000C001800060020000381C00000FE00001F217E9F20>67 D<00FFFFE000000F007800000F00
1C00000F000E00000F000700001E000700001E000380001E000380001E000380003C000380003C
000380003C000380003C000380007800078000780007800078000780007800078000F0000F0000
F0000F0000F0000E0000F0001E0001E0001C0001E0003C0001E000380001E000700003C000E000
03C001C00003C003800003C007000007803C0000FFFFF00000211F7E9E26>I<00FFFFFF000F00
0E000F0006000F0002000F0002001E0002001E0002001E0002001E0002003C0404003C0400003C
0400003C0C0000781800007FF800007818000078180000F0100000F0100000F0100000F0000401
E0000801E0000801E0001001E0001003C0002003C0006003C0004003C001C0078007C0FFFFFF80
201F7E9E22>I<00FFFFFF000F000E000F0006000F0002000F0002001E0002001E0002001E0002
001E0002003C0004003C0400003C0400003C04000078080000781800007FF8000078180000F010
0000F0100000F0100000F0100001E0000001E0000001E0000001E0000003C0000003C0000003C0
000003C0000007C00000FFFE0000201F7E9E1D>I<00007E0100038183000E00460038002E0070
001E00E0000E01C0000C0380000C0700000C0F00000C1E0000081E0000083C0000003C00000078
000000780000007800000078000000F0000000F0007FFCF00001E0F00001E0F00003C0700003C0
700003C0700003C038000780380007801C000F800C000B80060033000380C100007F000020217E
9F24>I<00FFF9FFF0000F801F00000F001E00000F001E00000F001E00001E003C00001E003C00
001E003C00001E003C00003C007800003C007800003C007800003C007800007800F000007FFFF0
00007800F000007800F00000F001E00000F001E00000F001E00000F001E00001E003C00001E003
C00001E003C00001E003C00003C007800003C007800003C007800003C007800007C00F8000FFF8
FFF800241F7E9E26>I<00FFFC000F80000F00000F00000F00001E00001E00001E00001E00003C
00003C00003C00003C0000780000780000780000780000F00000F00000F00000F00001E00001E0
0001E00001E00003C00003C00003C00003C00007C000FFFC00161F7F9E14>I<00FFF80FF8000F
8003E0000F000380000F000200000F000400001E000800001E002000001E004000001E00800000
3C010000003C040000003C080000003C180000007838000000787C000000793C0000007A3C0000
00F41E000000F81E000000F01E000000F00F000001E00F000001E00F000001E007800001E00780
0003C007800003C003C00003C003C00003C003C00007C003E000FFFC3FFC00251F7E9E27>75
D<00FF00001FF0000F00003F00000B80003E00000B80005E00000B80005E0000138000BC000013
80013C00001380013C00001380023C000023800278000023800478000023800878000021C00878
000041C010F0000041C020F0000041C020F0000041C040F0000081C041E0000081C081E0000081
C101E0000081C101E0000100E203C0000100E203C0000100E403C0000100E803C0000200E80780
000200F00780000200F00780000600E00780000F00C00F8000FFE0C1FFF8002C1F7E9E2C>77
D<00FF803FF0000F800780000F800200000BC00200000BC002000013C004000011E004000011E0
04000011E004000020F008000020F008000020F808000020780800004078100000403C10000040
3C100000403C100000801E200000801E200000801E200000800F200001000F400001000F400001
0007C000010007C00002000780000200038000020003800006000380000F00010000FFE0010000
241F7E9E25>I<0001FC0000070700001C01C0003000E000E0006001C000700380007007800038
070000380E0000381E0000381C0000383C0000383C000038780000787800007878000078780000
78F00000F0F00000F0F00000E0F00001E0F00001C0F00003C0700003807000070078000F003800
1E0038003C001C0070000E00E0000783800001FC00001D217E9F23>I<00FFFFC0000F0070000F
0038000F001C000F001E001E001E001E001E001E001E001E001E003C003C003C003C003C007800
3C0070007800E000780380007FFE000078000000F0000000F0000000F0000000F0000001E00000
01E0000001E0000001E0000003C0000003C0000003C0000003C0000007C00000FFFC00001F1F7E
9E1D>I<0001FC0000070700001C01C0003000E000E000E001C000700380007007800078070000
380F0000381E0000381E0000383C0000383C00007878000078780000787800007878000078F000
00F0F00000F0F00000E0F00001E0F00001C0F00003C070000380701C070070600F0038811E0038
813C001C8170000E81E0000783808001FD0080000101800001010000038300000386000003FE00
0003FC000001F8000000F0001D297E9F24>I<00FFFF80000F01E0000F0070000F0038000F003C
001E003C001E003C001E003C001E003C003C0078003C0078003C00F0003C01E00078038000780F
00007FF80000781C0000F00E0000F00F0000F0070000F0078001E00F0001E00F0001E00F0001E0
0F0003C01E0003C01E0203C01E0203C01E0407C00E04FFFC0718000003E01F207E9E23>I<0007
E0800018118000300B000060070000C0070001C003000180020003800200038002000380020003
8000000380000003C0000003F8000003FF800001FFC00000FFE000003FF0000003F0000000F000
0000700000007000000070002000700020007000200060006000E0006000C0006001C000700180
00E8030000C60E000081F8000019217D9F1C>I<0FFFFFFC1E03C0381803C0181003C0082003C0
0820078008600780084007800840078008800F0010000F0000000F0000000F0000001E0000001E
0000001E0000001E0000003C0000003C0000003C0000003C000000780000007800000078000000
78000000F0000000F0000000F0000000F0000001F000007FFFC0001E1F7F9E1B>I<7FFC1FF807
C003C00780010007800100078001000F0002000F0002000F0002000F0002001E0004001E000400
1E0004001E0004003C0008003C0008003C0008003C000800780010007800100078001000780010
00F0002000F0002000F0002000F0004000F0004000700080007001000030020000380400000C18
000007E000001D207C9E1F>I<FFF801FF0F8000780F0000600F0000400F800040078000800780
0080078001000780020007800200078004000780080007C0080003C0100003C0100003C0200003
C0400003C0400003C0800003C1800003C1000003E2000001E2000001E4000001E8000001E80000
01F0000001F0000001E0000001C0000000C000000080000020207E9E1B>I<FFF03FFC1FF80F80
07C003C00F00078001800F00078001000F00078002000F00078002000F000F8004000F00178004
000F00178008000F00278018000F0027C010000F0043C020000F8043C020000F8083C040000781
83C04000078103C08000078203C08000078203C10000078403C20000078403C20000078803C400
00078803C40000079003C8000007A003C8000007A003D0000007C003F0000007C003E000000780
01C00000078001C000000700018000000300018000000200010000002D207E9E2B>I<00FFF83F
F8000FC00F80000F80060000078004000007C008000003C010000003C020000003E040000001E0
80000001F100000000F300000000F600000000FC0000000078000000007C000000007C00000000
7C00000000BE000000011E000000021E000000061F0000000C0F000000080F8000001007800000
20078000004007C000008003C000010003E000030003E0000F0007E000FFE01FFE00251F7F9E26
>I<FFF801FF0F8000780F8000600780004007C0008007C0018003C0010003E0020003E0040001
E0080001F0180000F0100000F0200000F8400000788000007D0000007D0000003E0000003C0000
003C0000003800000078000000780000007800000070000000F0000000F0000000F0000000F000
0001E000003FFF0000201F7F9E1A>I<00F1800389C00707800E03801C03803C03803807007807
00780700780700F00E00F00E00F00E00F00E10F01C20F01C20703C20705C40308C400F07801414
7E9318>97 D<0000780003F80000700000700000700000700000E00000E00000E00000E00001C0
0001C000F1C00389C00707800E03801C03803C0380380700780700780700780700F00E00F00E00
F00E00F00E10F01C20F01C20703C20705C40308C400F078015207E9F18>100
D<007C01C207010E011C013C013802780C7BF07C00F000F000F000F00070007001700230041838
07C010147E9315>I<001E3000713800E0F001C0700380700780700700E00F00E00F00E00F00E0
1E01C01E01C01E01C01E01C01E03801E03800E07800E0B8006170001E700000700000700000E00
000E00300E00781C00F038006070003FC000151D809316>103 D<00E001E001E000C000000000
000000000000000000000E00130023804380438043808700070007000E000E001C001C001C2038
4038403840388019000E000B1F7E9E10>105 D<01E0000FE00001C00001C00001C00001C00003
80000380000380000380000700000700000701E00706100E08700E10F00E20F00E40601C80001D
00001E00001FC000387000383800383800381C20703840703840703840701880E01880600F0014
207E9F18>107 D<1E07C07C00231861860023A032030043C03403004380380380438038038087
007007000700700700070070070007007007000E00E00E000E00E00E000E00E00E000E00E01C10
1C01C01C201C01C038201C01C038401C01C0184038038018801801800F0024147E9328>109
D<1E07802318C023A06043C0704380704380708700E00700E00700E00700E00E01C00E01C00E01
C00E03821C03841C07041C07081C03083803101801E017147E931B>I<1E1E0023210023C38043
C7804387804383008700000700000700000700000E00000E00000E00000E00001C00001C00001C
00001C000038000018000011147E9315>114 D<007C018203010603060706060E00078007F803
FC01FE001F00077007F006F006E004400820301FC010147E9315>I<00C000E001C001C001C001
C003800380FFF8038007000700070007000E000E000E000E001C001C001C001C10382038203820
384018800F000D1C7F9B10>I<0F01801183C02183E021C1E041C0E04380608380400700400700
400700400E00800E00800E00800E01000E01000C02000E04000E040006180001E00013147E9316
>118 D<03C1C00C62201034701038F02038F020386040700000700000700000700000E00000E0
0000E00000E02061C040F1C040F1C080E2C080446300383C0014147E931A>120
D<0F00601180702180E021C0E041C0E04380E08381C00701C00701C00701C00E03800E03800E03
800E03800E07000C07000C07000E0F00061E0003EE00000E00000E00001C007818007838007070
0060600021C0001F0000141D7E9316>I E /Fg 3 104 df<07E01FF83FFC7FFE7FFEFFFFFFFFFF
FFFFFFFFFFFFFFFFFFFFFF7FFE7FFE3FFC1FF807E010127D9317>15 D<000F0038006000E001C0
01C001C001C001C001C001C001C001C001C001C001C001C001C001C0038007001E00F8001E0007
00038001C001C001C001C001C001C001C001C001C001C001C001C001C001C001C000E000600038
000F102D7DA117>102 D<F8001E000700038001C001C001C001C001C001C001C001C001C001C0
01C001C001C001C001C000E000600038000F0038006000E001C001C001C001C001C001C001C001
C001C001C001C001C001C001C001C0038007001E00F800102D7DA117>I
E /Fh 56 123 df<000FE000007FF80000F81C0001E07C0003E07C0007C07C0007C07C0007C038
0007C0000007C0000007C0000007C1FE00FFFFFE00FFFFFE0007C03E0007C03E0007C03E0007C0
3E0007C03E0007C03E0007C03E0007C03E0007C03E0007C03E0007C03E0007C03E0007C03E0007
C03E0007C03E0007C03E003FF9FFC03FF9FFC01A20809F1D>12 D<0018007000E001C003800380
07000E000E001E001C003C003C007800780078007800F800F000F000F000F000F000F000F000F0
00F000F80078007800780078003C003C001C001E000E000E0007000380038001C000E000700018
0D2D7DA114>40 D<C000700038001C000E000E0007000380038003C001C001E001E000F000F000
F000F000F800780078007800780078007800780078007800F800F000F000F000F001E001E001C0
03C00380038007000E000E001C0038007000C0000D2D7DA114>I<387CFEFFFF7F3B030306060E
0C18702008107C860F>44 D<FFF0FFF0FFF0FFF00C047F8B11>I<387CFEFEFE7C3807077C860F>
I<00E00001E0000FE000FFE000F3E00003E00003E00003E00003E00003E00003E00003E00003E0
0003E00003E00003E00003E00003E00003E00003E00003E00003E00003E00003E00003E00003E0
0003E000FFFF80FFFF80111D7C9C1A>49 D<07F0001FFE00383F007C1F80FE0FC0FE0FC0FE0FE0
FE07E07C07E03807E0000FE0000FC0000FC0001F80001F00003E0000780000F00000E00001C000
0380600700600E00601C00E01FFFC03FFFC07FFFC0FFFFC0FFFFC0131D7D9C1A>I<01FC0007FF
000E0F801E0FC03F07E03F07E03F07E03F07E01E0FC0000FC0000F80001F0001FC0001FC00000F
800007C00003E00003F00003F83803F87C03F8FE03F8FE03F8FE03F0FC03F07807E03C0FC01FFF
8003FC00151D7E9C1A>I<0001C00003C00007C00007C0000FC0001FC0003BC00073C00063C000
C3C00183C00383C00703C00E03C00C03C01803C03803C07003C0E003C0FFFFFEFFFFFE0007C000
07C00007C00007C00007C00007C000FFFE00FFFE171D7F9C1A>I<6000007FFFF87FFFF87FFFF0
7FFFE07FFFE0E001C0C00380C00700C00E00000C00001C0000380000780000780000F00000F000
00F00001F00001F00001F00003F00003F00003F00003F00003F00003F00003F00003F00001E000
151E7D9D1A>55 D<01FC0007FF000E07801C01C01800E03800E03800E03C00E03F00E03FC1C01F
E3801FFF000FFE0007FF8007FFC01FFFE03C3FF0780FF07803F8F001F8F000F8F00078F00078F0
00707800707C00E03E03C00FFF8003FC00151D7E9C1A>I<01FC000FFF001F07803E03C07C03E0
7C01E0FC01F0FC01F0FC01F0FC01F8FC01F8FC01F8FC01F87C03F87C03F83E05F81FFDF807F9F8
0041F80001F03C01F07E01F07E03E07E03E07E07C03C0780381F001FFC0007F000151D7E9C1A>
I<387CFEFEFE7C38000000000000387CFEFEFE7C3807147C930F>I<07F8001FFE00381F80780F
80FC0FC0FC0FC0FC0FC0780FC0301F80001F00003E00007C0000700000E00000E00000C00000C0
0000C00000C00000C00000C00000000000000000000000000001C00007F00007F00007F00007F0
0007F00001C00012207D9F19>63 D<0000E000000000E000000001F000000001F000000001F000
000003F800000003F800000006FC00000006FC0000000EFE0000000C7E0000000C7E000000183F
000000183F000000303F800000301F800000701FC00000600FC00000600FC00000C007E00000FF
FFE00001FFFFF000018003F000018003F000030001F800030001F800060001FC00060000FC000E
0000FE00FFE00FFFE0FFE00FFFE0231F7E9E28>65 D<0007FC02003FFF0E00FE03DE03F000FE07
E0003E0FC0001E1F80001E3F00000E3F00000E7F0000067E0000067E000006FE000000FE000000
FE000000FE000000FE000000FE000000FE0000007E0000007E0000067F0000063F0000063F0000
0C1F80000C0FC0001807E0003803F0007000FE01C0003FFF800007FC001F1F7D9E26>67
D<FFFFFE0000FFFFFFC00007E007F00007E001F80007E000FC0007E0007E0007E0003F0007E000
3F0007E0001F8007E0001F8007E0001F8007E0001FC007E0001FC007E0001FC007E0001FC007E0
001FC007E0001FC007E0001FC007E0001FC007E0001FC007E0001F8007E0001F8007E0001F8007
E0003F0007E0003F0007E0007E0007E000FC0007E001F80007E007F000FFFFFFC000FFFFFE0000
221F7E9E28>I<FFFFFFE0FFFFFFE007E007E007E001E007E000E007E0006007E0007007E00030
07E0003007E0603007E0603007E0600007E0E00007E1E00007FFE00007FFE00007E1E00007E0E0
0007E0600007E0600C07E0600C07E0000C07E0001807E0001807E0001807E0003807E0007807E0
00F807E003F0FFFFFFF0FFFFFFF01E1F7E9E22>I<0007FC0200003FFF0E0000FE03DE0003F000
FE0007E0003E000FC0001E001F80001E003F00000E003F00000E007F000006007E000006007E00
000600FE00000000FE00000000FE00000000FE00000000FE00000000FE003FFFE0FE003FFFE07E
00007E007E00007E007F00007E003F00007E003F00007E001F80007E000FC0007E0007E0007E00
03F000FE0000FE01FE00003FFF8E000007FC0600231F7D9E29>71 D<FFFF0FFFF0FFFF0FFFF007
E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E00
07E0007E0007E0007E0007E0007E0007E0007E0007FFFFFE0007FFFFFE0007E0007E0007E0007E
0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E0007E000
7E0007E0007E0007E0007E0007E0007E00FFFF0FFFF0FFFF0FFFF0241F7E9E29>I<FFFFFFFF07
E007E007E007E007E007E007E007E007E007E007E007E007E007E007E007E007E007E007E007E0
07E007E007E007E007E007E007E0FFFFFFFF101F7E9E14>I<FFE000003FF8FFF000007FF807F0
00007F0006F80000DF0006F80000DF0006F80000DF00067C00019F00067C00019F00063E00031F
00063E00031F00061F00061F00061F00061F00060F800C1F00060F800C1F000607C0181F000607
C0181F000607C0181F000603E0301F000603E0301F000601F0601F000601F0601F000600F8C01F
000600F8C01F0006007D801F0006007D801F0006003F001F0006003F001F0006003F001F000600
1E001F00FFF01E03FFF8FFF00C03FFF82D1F7E9E32>77 D<FFE000FFF0FFF000FFF007F8000600
07FC00060007FE00060006FE000600067F000600063F800600061FC00600060FE00600060FE006
000607F006000603F806000601FC06000600FE060006007F060006007F060006003F860006001F
C60006000FE600060007F600060003FE00060003FE00060001FE00060000FE000600007E000600
003E000600001E000600001E00FFF0000E00FFF0000600241F7E9E29>I<001FF80000FFFF0001
F81F8007E007E00FC003F01F8001F81F0000F83F0000FC7F0000FE7E00007E7E00007EFE00007F
FE00007FFE00007FFE00007FFE00007FFE00007FFE00007FFE00007FFE00007F7E00007E7F0000
FE7F0000FE3F0000FC3F8001FC1F8001F80FC003F007E007E001F81F8000FFFF00001FF800201F
7D9E27>I<FFFFFE00FFFFFF8007E00FE007E003F007E001F807E001F807E001FC07E001FC07E0
01FC07E001FC07E001FC07E001F807E001F807E003F007E00FE007FFFF8007FFFE0007E0000007
E0000007E0000007E0000007E0000007E0000007E0000007E0000007E0000007E0000007E00000
07E00000FFFF0000FFFF00001E1F7E9E24>I<FFFFF80000FFFFFF000007E01FC00007E007E000
07E003F00007E003F00007E003F80007E003F80007E003F80007E003F80007E003F00007E003F0
0007E007E00007E01FC00007FFFF000007FFFC000007E03E000007E01F000007E01F800007E00F
C00007E00FC00007E00FC00007E00FE00007E00FE00007E00FE00007E00FE03007E00FF03007E0
0FF07007E007F860FFFF01FFE0FFFF007F80241F7E9E27>82 D<03FC080FFF381E03F83800F870
0078700038F00038F00018F00018F80000FC00007FC0007FFE003FFF801FFFE00FFFF007FFF000
FFF80007F80000FC00007C00003CC0003CC0003CC0003CE00038E00078F80070FE01E0E7FFC081
FF00161F7D9E1D>I<7FFFFFFC7FFFFFFC7C07E07C7007E01C6007E00C6007E00CE007E00EC007
E006C007E006C007E006C007E0060007E0000007E0000007E0000007E0000007E0000007E00000
07E0000007E0000007E0000007E0000007E0000007E0000007E0000007E0000007E0000007E000
0007E00003FFFFC003FFFFC01F1E7E9D24>I<FFFE003FF8FFFE003FF807E000038007E0000300
07F000070003F000060003F8000E0001F8000C0001FC000C0000FC00180000FC001800007E0030
00007E003000003F006000003F006000003F80E000001F80C000001FC1C000000FC18000000FE1
80000007E300000007E300000003F600000003F600000003FE00000001FC00000001FC00000000
F800000000F8000000007000000000700000251F7F9E28>86 D<FFFE0FFFC0FFE0FFFE0FFFC0FF
E00FC000FC000E000FE000FC000E0007E000FE000C0007E000FE000C0003F000FE00180003F001
FF00180003F001BF00180001F801BF00300001F8031F80300001FC031F80700000FC031F806000
00FC060FC06000007E060FC0C000007E0E0FE0C000007E0C07E0C000003F0C07E18000003F1803
F18000003F9803F38000001F9803F30000001FB001FB0000000FF001FE0000000FF001FE000000
0FE000FE00000007E000FC00000007C0007C00000007C0007C00000003C0007800000003800038
000000018000300000331F7F9E36>I<FFFE003FF8FFFE003FF807F000038007F000070003F800
060001FC000C0001FC001C0000FE001800007F003000003F807000003F806000001FC0C000000F
E1C000000FE180000007F300000003FF00000001FE00000001FC00000000FC00000000FC000000
00FC00000000FC00000000FC00000000FC00000000FC00000000FC00000000FC00000000FC0000
0000FC0000001FFFE000001FFFE000251F7F9E28>89 D<07FC001FFF003F0F803F07C03F03E03F
03E00C03E00003E0007FE007FBE01F03E03C03E07C03E0F803E0F803E0F803E0FC05E07E0DE03F
F9FE0FE07E17147F9319>97 D<FF0000FF00001F00001F00001F00001F00001F00001F00001F00
001F00001F00001F00001F1FC01F7FF01FE0F81F807C1F007E1F003E1F003E1F003F1F003F1F00
3F1F003F1F003F1F003F1F003E1F003E1F007C1F807C1EC1F81C7FE0181F8018207E9F1D>I<01
FE0007FF801F0FC03E0FC03E0FC07C0FC07C0300FC0000FC0000FC0000FC0000FC0000FC00007C
00007E00003E00603F00C01F81C007FF0001FC0013147E9317>I<0007F80007F80000F80000F8
0000F80000F80000F80000F80000F80000F80000F80000F801F8F80FFEF81F83F83E01F87E00F8
7C00F87C00F8FC00F8FC00F8FC00F8FC00F8FC00F8FC00F87C00F87C00F87E00F83E01F81F07F8
0FFEFF03F8FF18207E9F1D>I<01FE0007FF801F83E03F01F07E00F07E00F8FC00F8FC00F8FFFF
F8FFFFF8FC0000FC0000FC00007C00007E00003E00183F00380F807007FFE000FF8015147F9318
>I<001F8000FFC001F3E003E7E003C7E007C7E007C3C007C00007C00007C00007C00007C000FF
FC00FFFC0007C00007C00007C00007C00007C00007C00007C00007C00007C00007C00007C00007
C00007C00007C00007C00007C0003FFC003FFC0013207F9F10>I<01FC3C07FFFE0F079E1E03DE
3E03E03E03E03E03E03E03E03E03E01E03C00F07800FFF0009FC001800001800001C00001FFF80
0FFFF007FFF81FFFFC3C007C70003EF0001EF0001EF0001E78003C78003C3F01F80FFFE001FF00
171E7F931A>I<FF0000FF00001F00001F00001F00001F00001F00001F00001F00001F00001F00
001F00001F0FC01F3FE01F61F01FC0F81F80F81F00F81F00F81F00F81F00F81F00F81F00F81F00
F81F00F81F00F81F00F81F00F81F00F81F00F8FFE3FFFFE3FF18207D9F1D>I<1C003F007F007F
007F003F001C00000000000000000000000000FF00FF001F001F001F001F001F001F001F001F00
1F001F001F001F001F001F001F001F00FFE0FFE00B217EA00F>I<FF0000FF00001F00001F0000
1F00001F00001F00001F00001F00001F00001F00001F00001F01FE1F01FE1F00F01F01C01F0380
1F07001F1E001F38001F7C001FFE001FFF001F1F001E0F801E07C01E07E01E03F01E01F01E00F8
FFC3FFFFC3FF18207E9F1C>107 D<FF00FF001F001F001F001F001F001F001F001F001F001F00
1F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F00FFE0FF
E00B207E9F0F>I<FE0FE03F80FE1FF07FC01E70F9C3E01E407D01F01E807E01F01F807E01F01F
007C01F01F007C01F01F007C01F01F007C01F01F007C01F01F007C01F01F007C01F01F007C01F0
1F007C01F01F007C01F01F007C01F01F007C01F0FFE3FF8FFEFFE3FF8FFE27147D932C>I<FE0F
C0FE3FE01E61F01EC0F81E80F81F00F81F00F81F00F81F00F81F00F81F00F81F00F81F00F81F00
F81F00F81F00F81F00F81F00F8FFE3FFFFE3FF18147D931D>I<01FF0007FFC01F83F03E00F83E
00F87C007C7C007CFC007EFC007EFC007EFC007EFC007EFC007E7C007C7C007C3E00F83E00F81F
83F007FFC001FF0017147F931A>I<FF1FC0FF7FF01FE1F81F80FC1F007E1F007E1F003E1F003F
1F003F1F003F1F003F1F003F1F003F1F003E1F007E1F007C1F80FC1FC1F81F7FE01F1F801F0000
1F00001F00001F00001F00001F00001F0000FFE000FFE000181D7E931D>I<FE3E00FE7F801ECF
C01E8FC01E8FC01F8FC01F03001F00001F00001F00001F00001F00001F00001F00001F00001F00
001F00001F0000FFF000FFF00012147E9316>114 D<0FE63FFE701E600EE006E006F800FFC07F
F83FFC1FFE03FE001FC007C007E007F006F81EFFFCC7F010147E9315>I<018001800180038003
80038007800F803F80FFFCFFFC0F800F800F800F800F800F800F800F800F800F800F860F860F86
0F860F8607CC03F801F00F1D7F9C14>I<FF07F8FF07F81F00F81F00F81F00F81F00F81F00F81F
00F81F00F81F00F81F00F81F00F81F00F81F00F81F00F81F01F81F01F80F06F807FCFF03F8FF18
147D931D>I<FFE07F80FFE07F801F001C000F8018000F80180007C0300007C0300003E0600003
E0600001F0C00001F0C00001F9C00000F9800000FF8000007F0000007F0000003E0000003E0000
001C0000001C000019147F931C>I<FFE7FE1FE0FFE7FE1FE01F00F007001F00F803000F80F806
000F80F8060007C1BC0C0007C1BC0C0007C1BE0C0003E31E180003E31E180001F60F300001F60F
300001F60FB00000FC07E00000FC07E000007803C000007803C000007803C00000300180002314
7F9326>I<FFE1FF00FFE1FF000F80700007C0E00007E0C00003E1800001F3800000FF0000007E
0000003E0000003F0000007F8000006F800000C7C0000183E0000381F0000701F8000E00FC00FF
81FF80FF81FF8019147F931C>I<FFE07F80FFE07F801F001C000F8018000F80180007C0300007
C0300003E0600003E0600001F0C00001F0C00001F9C00000F9800000FF8000007F0000007F0000
003E0000003E0000001C0000001C0000001800000018000078300000FC300000FC600000C0E000
00E1C000007F8000001E000000191D7F931C>I<3FFFE03FFFE03C0FC0381FC0701F80603F0060
7E0060FE0000FC0001F80003F00007E0600FE0600FC0601F80E03F00C07F01C07E03C0FFFFC0FF
FFC013147F9317>I E /Fi 50 123 df<00003FE00000E0100001803800038078000300780007
0030000700000007000000070000000E0000000E0000000E000000FFFFE0000E00E0001C01C000
1C01C0001C01C0001C01C0001C0380003803800038038000380380003807000038070000700700
0070071000700E2000700E2000700E2000E00E2000E0064000E0038000E0000000C0000001C000
0001C000003180000079800000F3000000620000003C0000001D29829F1A>12
D<7FF0FFE07FE00C037D8A10>45 D<70F8F8F0E005057B840E>I<070F1F1F0E00000000000000
00000070F8F8F0E008147B930E>58 D<00000200000006000000060000000E0000001E0000001E
0000003F0000002F0000004F0000004F0000008F0000010F0000010F0000020F0000020F000004
0F00000C0F0000080F0000100F0000100F0000200F80003FFF800040078000C007800080078001
000780010007800200078002000780060007801E000F80FF807FF81D207E9F22>65
D<01FFFFC0001E00F0001E0078001E0038001E003C003C003C003C003C003C003C003C003C0078
007800780078007800F0007801E000F0078000FFFE0000F00F8000F003C001E001C001E001E001
E001E001E001E003C001E003C001E003C001E003C001C0078003C00780078007800F0007801E00
0F007800FFFFE0001E1F7D9E20>I<0000FE0200078186001C004C0038003C0060003C00C0001C
01C0001803800018070000180F0000181E0000101E0000103C0000003C00000078000000780000
007800000078000000F0000000F0000000F0000000F0000000F000008070000080700000807000
01003800010038000200180004000C001800060020000381C00000FE00001F217A9F21>I<01FF
FF80001E00E0001E0070001E0038001E001C003C001C003C000E003C000E003C000E0078000E00
78000E0078000E0078000E00F0001E00F0001E00F0001E00F0001E01E0003C01E0003C01E0003C
01E0007803C0007003C0007003C000E003C001C0078001C00780038007800E0007801C000F0070
00FFFFC0001F1F7D9E22>I<01FFFFFE001E001C001E000C001E0004001E0004003C0004003C00
04003C0004003C00040078080800780800007808000078180000F0300000FFF00000F0300000F0
300001E0200001E0200001E0200001E0001003C0002003C0002003C0004003C000400780008007
80018007800100078007000F001F00FFFFFE001F1F7D9E1F>I<01FFFFFC001E0038001E001800
1E0008001E0008003C0008003C0008003C0008003C000800780010007808000078080000780800
00F0100000F0300000FFF00000F0300001E0200001E0200001E0200001E0200003C0000003C000
0003C0000003C00000078000000780000007800000078000000F800000FFF800001E1F7D9E1E>
I<0000FC040007030C001C00980030007800E0007801C000380380003003800030070000300E00
00301E0000201E0000203C0000003C00000078000000780000007800000078000000F0000000F0
00FFF0F0000780F0000780F0000F0070000F0070000F0070000F0070001E0038001E0018003E00
1C002E000E00CC000383040000FC00001E217A9F23>I<01FFF3FFE0001F003E00001E003C0000
1E003C00001E003C00003C007800003C007800003C007800003C007800007800F000007800F000
007800F000007800F00000F001E00000FFFFE00000F001E00000F001E00001E003C00001E003C0
0001E003C00001E003C00003C007800003C007800003C007800003C007800007800F000007800F
000007800F000007800F00000F801F0000FFF1FFE000231F7D9E22>I<01FFF0001F00001E0000
1E00001E00003C00003C00003C00003C0000780000780000780000780000F00000F00000F00000
F00001E00001E00001E00001E00003C00003C00003C00003C0000780000780000780000780000F
8000FFF800141F7D9E12>I<01FFF03FE0001F000F80001E000E00001E000800001E001000003C
002000003C004000003C010000003C020000007804000000780800000078100000007830000000
F0F0000000F1F8000000F278000000F478000001E83C000001F03C000001E03C000001E01E0000
03C01E000003C01E000003C00F000003C00F000007800F00000780078000078007800007800780
000F8007C000FFF03FF800231F7D9E23>75 D<01FFF800001F0000001E0000001E0000001E0000
003C0000003C0000003C0000003C00000078000000780000007800000078000000F0000000F000
0000F0000000F0000001E0000001E0000001E0000001E0008003C0010003C0010003C0030003C0
0200078006000780060007800C0007801C000F007800FFFFF800191F7D9E1D>I<01FE00007FC0
001E0000FC00001E0000F80000170001780000170001780000270002F00000270004F000002700
04F00000270008F00000470009E00000470011E00000470021E00000470021E00000870043C000
00838043C00000838083C00000838083C000010381078000010382078000010382078000010384
0780000203840F00000203880F00000203900F00000203900F00000401E01E00000401E01E0000
0401C01E00000C01801E00001C01803E0000FF8103FFC0002A1F7D9E29>I<01FF007FE0001F00
0F00001F0004000017800400001780040000278008000023C008000023C008000023C008000041
E010000041E010000041F010000040F010000080F0200000807820000080782000008078200001
003C400001003C400001003C400001001E400002001E800002001E800002000F800002000F8000
04000F0000040007000004000700000C000700001C00020000FF80020000231F7D9E22>I<0001
FC0000070700001C01C0003000E000E0006001C000700380007007800038070000380E0000381E
0000381C0000383C0000383C00003878000078780000787800007878000078F00000F0F00000F0
F00000E0F00001E0F00001C0F00003C0700003807000070078000F0038001E0038003C001C0070
000E00E0000783800001FC00001D217A9F23>I<01FFFF80001E00E0001E0070001E0038001E00
3C003C003C003C003C003C003C003C003C0078007800780078007800F0007800E000F003C000F0
0F0000FFFC0000F0000001E0000001E0000001E0000001E0000003C0000003C0000003C0000003
C00000078000000780000007800000078000000F800000FFF000001E1F7D9E1F>I<01FFFF0000
1E03C0001E00E0001E0070001E0078003C0078003C0078003C0078003C0078007800F0007800F0
007801E0007801C000F0070000F01E0000FFF00000F0380001E01C0001E01E0001E00E0001E00F
0003C01E0003C01E0003C01E0003C01E0007803C0007803C0807803C0807803C100F801C10FFF0
0C20000007C01D207D9E21>82 D<0007E040001C18C0003005800060038000C0038001C0018001
8001000380010003800100038001000380000003C0000003C0000003F8000001FF800001FFE000
007FF000001FF0000001F800000078000000780000003800000038002000380020003800200030
0060007000600060006000E0007000C000E8038000C606000081F800001A217D9F1A>I<0FFFFF
F01E0780E0180780201007802020078020200F0020600F0020400F0020400F0020801E0040001E
0000001E0000001E0000003C0000003C0000003C0000003C000000780000007800000078000000
78000000F0000000F0000000F0000000F0000001E0000001E0000001E0000001E0000003E00000
FFFF00001C1F789E21>I<7FFC1FF807C003C00780010007800100078001000F0002000F000200
0F0002000F0002001E0004001E0004001E0004001E0004003C0008003C0008003C0008003C0008
0078001000780010007800100078001000F0002000F0002000F0002000F0004000F00040007000
80007001000030020000380400000C18000007E000001D20779E22>I<FFF007FC0F8000E00F00
00C00F0000800F0001000F0001000F0002000F0004000F0004000F800800078008000780100007
80200007802000078040000780400007808000078100000781000007C2000003C2000003C40000
03C8000003C8000003D0000003D0000003E0000003C0000003C000000380000001800000010000
001E20779E22>I<FFF1FFC0FF801F003E001C001F003C0018000F003C0010000F003C0010000F
003C0020000F003C0020000F003E0040000F003E00C0000F005E0080000F005E0100000F009E01
00000F009E0200000F011E0200000F021E0400000F021E0400000F041E0800000F041E0800000F
081E1000000F081E2000000F101E2000000F101E4000000F201E4000000F601E8000000FC01E80
000007801F00000007801F00000007001E00000007001E00000006000C00000006000800000004
00080000002920779E2D>I<FFF003FC1F8000E00F0000C00F800080078001000780020007C004
0003C00C0003C0080003E0100003E0200001E0400001F0400001F0800000F1000000FA000000FE
0000007C000000780000007800000070000000F0000000F0000000F0000000E0000001E0000001
E0000001E0000001E0000003C000003FFC00001E1F779E22>89 D<00F1800389C00707800E0380
1C03803C0380380700780700780700780700F00E00F00E00F00E00F00E20F01C40F01C40703C40
705C40308C800F070013147C9317>97 D<07803F8007000700070007000E000E000E000E001C00
1C001CF01D0C3A0E3C0E380F380F700F700F700F700FE01EE01EE01EE01CE03CE038607060E031
C01F0010207B9F15>I<007E0001C1000300800E07801E07801C07003C02007800007800007800
00F00000F00000F00000F00000F0000070010070020030040018380007C00011147C9315>I<00
00780003F80000700000700000700000700000E00000E00000E00000E00001C00001C000F1C003
89C00707800E03801C03803C0380380700780700780700780700F00E00F00E00F00E00F00E20F0
1C40F01C40703C40705C40308C800F070015207C9F17>I<007C01C207010E011C013C01380278
0C7BF07C00F000F000F000F0007000700170023804183807C010147C9315>I<00007800019C00
033C00033C000718000700000700000E00000E00000E00000E00000E0001FFE0001C00001C0000
1C00001C0000380000380000380000380000380000700000700000700000700000700000700000
E00000E00000E00000E00000C00001C00001C0000180003180007B0000F300006600003C000016
29829F0E>I<003C6000E27001C1E00380E00700E00F00E00E01C01E01C01E01C01E01C03C0380
3C03803C03803C03803C07003C07001C0F001C17000C2E0003CE00000E00000E00001C00001C00
301C00783800F0700060E0003F8000141D7E9315>I<01E0000FE00001C00001C00001C00001C0
00038000038000038000038000070000070000071E000763000E81800F01C00E01C00E01C01C03
801C03801C03801C0380380700380700380700380E10700E20700C20701C20700C40E00CC06007
0014207D9F17>I<00C001E001E001C000000000000000000000000000000E0033002300438043
00470087000E000E000E001C001C001C003840388030807080310033001C000B1F7C9E0E>I<01
E0000FE00001C00001C00001C00001C0000380000380000380000380000700000700000703C007
04200E08E00E11E00E21E00E40C01C80001D00001E00001FC00038E00038700038700038384070
7080707080707080703100E03100601E0013207D9F15>107 D<03C01FC0038003800380038007
000700070007000E000E000E000E001C001C001C001C0038003800380038007000700070007100
E200E200E200E200640038000A207C9F0C>I<1C0F80F0002630C318004740640C004780680E00
4700700E004700700E008E00E01C000E00E01C000E00E01C000E00E01C001C01C038001C01C038
001C01C038001C01C0708038038071003803806100380380E10038038062007007006600300300
380021147C9325>I<1C0F802630C04740604780604700704700708E00E00E00E00E00E00E00E0
1C01C01C01C01C01C01C03843803883803083807083803107003303001C016147C931A>I<007C
0001C3000301800E01C01E01C01C01E03C01E07801E07801E07801E0F003C0F003C0F003C0F007
80F00700700F00700E0030180018700007C00013147C9317>I<01C1E002621804741C04781C04
701E04701E08E01E00E01E00E01E00E01E01C03C01C03C01C03C01C0380380780380700380E003
C1C0072380071E000700000700000E00000E00000E00000E00001C00001C0000FFC000171D8093
17>I<1C1E002661004783804787804707804703008E00000E00000E00000E00001C00001C0000
1C00001C000038000038000038000038000070000030000011147C9313>114
D<00FC030206010C030C070C060C000F800FF007F803FC003E000E700EF00CF00CE00840102060
1F8010147D9313>I<018001C0038003800380038007000700FFF007000E000E000E000E001C00
1C001C001C003800380038003820704070407080708031001E000C1C7C9B0F>I<0E00C03300E0
2301C04381C04301C04701C08703800E03800E03800E03801C07001C07001C07001C07101C0E20
180E20180E201C1E200C264007C38014147C9318>I<0E03803307802307C04383C04301C04700
C08700800E00800E00800E00801C01001C01001C01001C02001C02001C04001C04001C08000E30
0003C00012147C9315>I<0E00C1C03300E3C02301C3E04381C1E04301C0E04701C06087038040
0E0380400E0380400E0380401C0700801C0700801C0700801C0701001C0701001C0602001C0F02
000C0F04000E13080003E1F0001B147C931E>I<0383800CC4401068E01071E02071E02070C040
E00000E00000E00000E00001C00001C00001C00001C040638080F38080F38100E5810084C60078
780013147D9315>I<0E00C03300E02301C04381C04301C04701C08703800E03800E03800E0380
1C07001C07001C07001C07001C0E00180E00180E001C1E000C3C0007DC00001C00001C00003800
F03800F07000E06000C0C0004380003E0000131D7C9316>I<01C04003E08007F1800C1F000802
000004000008000010000020000040000080000100000200000401000802001002003E0C0063FC
0041F80080E00012147D9313>I E /Fj 40 122 df<FFFF80FFFF80FFFF80FFFF80FFFF80FFFF
8011067F9017>45 D<000E00001E00007E0007FE00FFFE00FFFE00F8FE0000FE0000FE0000FE00
00FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE00
00FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE00
7FFFFE7FFFFE7FFFFE17277BA622>49 D<00FF800003FFF0000FFFFC001F03FE003800FF007C00
7F80FE003FC0FF003FC0FF003FE0FF001FE0FF001FE07E001FE03C003FE000003FE000003FC000
003FC000007F8000007F000000FE000000FC000001F8000003F0000003E00000078000000F0000
001E0000003C00E0007000E000E000E001C001C0038001C0070001C00FFFFFC01FFFFFC03FFFFF
C07FFFFFC0FFFFFF80FFFFFF80FFFFFF801B277DA622>I<007F800003FFF00007FFFC000F81FE
001F00FF003F80FF003F807F803F807F803F807F801F807F800F007F800000FF000000FF000000
FE000001FC000001F8000007F00000FFC00000FFF0000001FC0000007E0000007F0000007F8000
003FC000003FC000003FE000003FE03C003FE07E003FE0FF003FE0FF003FE0FF003FC0FF007FC0
7E007F807C007F003F01FE001FFFFC0007FFF00000FF80001B277DA622>I<00000E0000001E00
00003E0000007E000000FE000000FE000001FE000003FE0000077E00000E7E00000E7E00001C7E
0000387E0000707E0000E07E0000E07E0001C07E0003807E0007007E000E007E000E007E001C00
7E0038007E0070007E00E0007E00FFFFFFF8FFFFFFF8FFFFFFF80000FE000000FE000000FE0000
00FE000000FE000000FE000000FE000000FE00007FFFF8007FFFF8007FFFF81D277EA622>I<0C
0003000F803F000FFFFE000FFFFC000FFFF8000FFFF0000FFFE0000FFFC0000FFE00000E000000
0E0000000E0000000E0000000E0000000E0000000E7FC0000FFFF8000F80FC000E003E000C003F
0000001F8000001FC000001FC000001FE000001FE018001FE07C001FE0FE001FE0FE001FE0FE00
1FE0FE001FC0FC001FC078003F8078003F803C007F001F01FE000FFFF80003FFF00000FF80001B
277DA622>I<0007F000003FFC0000FFFE0001FC0F0003F01F8007E03F800FC03F801FC03F801F
803F803F801F003F8000007F0000007F0000007F000000FF000000FF0FC000FF3FF800FF707C00
FFC03E00FFC03F00FF801F80FF801FC0FF001FC0FF001FE0FF001FE0FF001FE07F001FE07F001F
E07F001FE07F001FE03F001FE03F001FC01F801FC01F803F800FC03F0007E07E0003FFFC0000FF
F000003FC0001B277DA622>I<380000003E0000003FFFFFF03FFFFFF03FFFFFF07FFFFFE07FFF
FFC07FFFFF807FFFFF0070000E0070000E0070001C00E0003800E0007000E000E0000000E00000
01C000000380000007800000078000000F0000000F0000001F0000001F0000003F0000003E0000
003E0000007E0000007E0000007E0000007E000000FE000000FE000000FE000000FE000000FE00
0000FE000000FE000000FE0000007C0000003800001C297CA822>I<003FC00001FFF00003FFFC
0007C07E000F003F001E001F001E000F803E000F803E000F803F000F803F000F803FC00F003FF0
1F001FFC1E001FFE3C000FFFF80007FFE00003FFF80001FFFC0001FFFE0007FFFF000F0FFF801E
03FFC03C01FFC07C007FE078001FE0F80007E0F80007E0F80003E0F80003E0F80003E0F80003C0
7C0003C07C0007803F000F001FC03E000FFFFC0003FFF800007FC0001B277DA622>I<007F8000
01FFF00007FFF8000FE0FC001F807E003F803F007F003F007F001F80FF001F80FF001FC0FF001F
C0FF001FC0FF001FE0FF001FE0FF001FE0FF001FE07F001FE07F003FE03F003FE01F807FE00F80
7FE007C1DFE003FF9FE0007E1FE000001FE000001FC000001FC000001FC000003F801F003F803F
803F003F803F003F807E003F807C001F01F8001E03F0000FFFE00007FF800001FE00001B277DA6
22>I<000003800000000007C00000000007C0000000000FE0000000000FE0000000000FE00000
00001FF0000000001FF0000000003FF8000000003FF8000000003FF80000000073FC0000000073
FC00000000F3FE00000000E1FE00000000E1FE00000001C0FF00000001C0FF00000003C0FF8000
0003807F80000007807FC0000007003FC0000007003FC000000E003FE000000E001FE000001E00
1FF000001C000FF000001FFFFFF000003FFFFFF800003FFFFFF80000780007FC0000700003FC00
00700003FC0000E00001FE0000E00001FE0001E00001FF0001C00000FF0001C00000FF00FFFE00
1FFFFEFFFE001FFFFEFFFE001FFFFE2F297EA834>65 D<00003FF001800003FFFE0380000FFFFF
8780003FF007DF8000FF8001FF8001FE00007F8003FC00003F8007F000001F800FF000000F801F
E0000007801FE0000007803FC0000007803FC0000003807FC0000003807F80000003807F800000
0000FF8000000000FF8000000000FF8000000000FF8000000000FF8000000000FF8000000000FF
8000000000FF8000000000FF80000000007F80000000007F80000000007FC0000003803FC00000
03803FC0000003801FE0000003801FE0000007000FF00000070007F000000E0003FC00001E0001
FE00003C0000FF8000F800003FF007E000000FFFFFC0000003FFFF000000003FF8000029297CA8
32>67 D<FFFFFFFFE0FFFFFFFFE0FFFFFFFFE003FC001FE003FC0007F003FC0001F003FC0001F0
03FC0000F003FC00007003FC00007003FC00007003FC01C07803FC01C03803FC01C03803FC01C0
3803FC03C00003FC03C00003FC0FC00003FFFFC00003FFFFC00003FFFFC00003FC0FC00003FC03
C00003FC03C00003FC01C00E03FC01C00E03FC01C00E03FC01C01C03FC00001C03FC00001C03FC
00001C03FC00003C03FC00003803FC00007803FC0000F803FC0001F803FC0003F803FC001FF8FF
FFFFFFF0FFFFFFFFF0FFFFFFFFF027297DA82D>69 D<FFFFFCFFFFFCFFFFFC01FE0001FE0001FE
0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE
0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE0001FE
0001FE0001FE0001FE0001FE0001FE0001FE00FFFFFCFFFFFCFFFFFC16297EA81A>73
D<0000FFE000000007FFFC0000003FC07F8000007F001FC00001FC0007F00003F80003F80007F0
0001FC000FF00001FE001FE00000FF001FE00000FF003FC000007F803FC000007F807FC000007F
C07F8000003FC07F8000003FC07F8000003FC0FF8000003FE0FF8000003FE0FF8000003FE0FF80
00003FE0FF8000003FE0FF8000003FE0FF8000003FE0FF8000003FE0FF8000003FE0FF8000003F
E07F8000003FC07FC000007FC07FC000007FC03FC000007F803FC000007F801FE00000FF001FE0
0000FF000FF00001FE0007F00001FC0003F80003F80001FC0007F00000FF001FE000003FC07F80
00000FFFFE00000000FFE000002B297CA834>79 D<FFFFFFE00000FFFFFFFE0000FFFFFFFF8000
03FC007FE00003FC000FF00003FC0007F80003FC0007FC0003FC0003FC0003FC0003FE0003FC00
03FE0003FC0003FE0003FC0003FE0003FC0003FE0003FC0003FE0003FC0003FC0003FC0007F800
03FC0007F80003FC001FE00003FC007FC00003FFFFFE000003FFFFF0000003FC00FC000003FC00
7F000003FC003F800003FC003F800003FC001FC00003FC001FE00003FC001FE00003FC001FE000
03FC001FE00003FC001FE00003FC001FF00003FC001FF00003FC001FF00003FC001FF00703FC00
1FF80703FC000FF80703FC0007F80EFFFFF003FE1CFFFFF001FFF8FFFFF0003FF030297DA834>
82 D<007F806003FFF0E007FFF9E00F807FE01F001FE03E0007E07C0003E07C0001E0FC0001E0
FC0001E0FC0000E0FE0000E0FE0000E0FF000000FFC000007FFE00007FFFE0003FFFFC001FFFFE
000FFFFF8007FFFFC003FFFFE000FFFFE00007FFF000007FF000000FF8000007F8000003F86000
01F8E00001F8E00001F8E00001F8F00001F0F00001F0F80003F0FC0003E0FF0007C0FFE01F80F3
FFFF00E0FFFE00C01FF0001D297CA826>I<FFFFF0003FFF80FFFFF0003FFF80FFFFF0003FFF80
03FE000001E00001FE000001C00001FF000003C00000FF000003800000FF0000038000007F8000
070000007F8000070000007FC0000F0000003FC0000E0000003FE0001E0000001FE0001C000000
1FF0001C0000000FF000380000000FF0003800000007F8007000000007F8007000000007FC00F0
00000003FC00E000000003FE01E000000001FE01C000000001FF01C000000000FF038000000000
FF038000000000FF8780000000007F8700000000007FCF00000000003FCE00000000003FFE0000
0000001FFC00000000001FFC00000000000FF800000000000FF800000000000FF8000000000007
F0000000000007F0000000000003E0000000000003E0000000000001C000000031297FA834>86
D<01FF800007FFF0000F81F8001FC07E001FC07E001FC03F000F803F8007003F8000003F800000
3F8000003F80000FFF8000FFFF8007FC3F800FE03F803F803F803F003F807F003F80FE003F80FE
003F80FE003F80FE003F807E007F807F00DF803F839FFC0FFF0FFC01FC03FC1E1B7E9A21>97
D<001FF80000FFFE0003F01F0007E03F800FC03F801F803F803F801F007F800E007F0000007F00
0000FF000000FF000000FF000000FF000000FF000000FF000000FF0000007F0000007F0000007F
8000003F8001C01F8001C00FC0038007E0070003F01E0000FFFC00001FE0001A1B7E9A1F>99
D<00003FF80000003FF80000003FF800000003F800000003F800000003F800000003F800000003
F800000003F800000003F800000003F800000003F800000003F800000003F800000003F800001F
E3F80000FFFBF80003F03FF80007E00FF8000FC007F8001F8003F8003F8003F8007F0003F8007F
0003F8007F0003F800FF0003F800FF0003F800FF0003F800FF0003F800FF0003F800FF0003F800
FF0003F8007F0003F8007F0003F8007F0003F8003F8003F8001F8003F8000F8007F80007C00FF8
0003F03BFF8000FFF3FF80003FC3FF80212A7EA926>I<003FE00001FFF80003F07E0007C01F00
0F801F801F800F803F800FC07F000FC07F0007C07F0007E0FF0007E0FF0007E0FFFFFFE0FFFFFF
E0FF000000FF000000FF0000007F0000007F0000007F0000003F8000E01F8000E00FC001C007E0
038003F81F0000FFFE00001FF0001B1B7E9A20>I<0007F0003FFC00FE3E01F87F03F87F03F07F
07F07F07F03E07F00007F00007F00007F00007F00007F00007F000FFFFC0FFFFC0FFFFC007F000
07F00007F00007F00007F00007F00007F00007F00007F00007F00007F00007F00007F00007F000
07F00007F00007F00007F00007F00007F00007F0007FFF807FFF807FFF80182A7EA915>I<00FF
81F003FFE7F80FC1FE7C1F80FC7C1F007C383F007E107F007F007F007F007F007F007F007F007F
007F007F007F003F007E001F007C001F80FC000FC1F8001FFFE00018FF80003800000038000000
3C0000003E0000003FFFF8001FFFFF001FFFFF800FFFFFC007FFFFE01FFFFFF03E0007F07C0001
F8F80000F8F80000F8F80000F8F80000F87C0001F03C0001E01F0007C00FC01F8003FFFE00007F
F0001E287E9A22>I<FFE0000000FFE0000000FFE00000000FE00000000FE00000000FE0000000
0FE00000000FE00000000FE00000000FE00000000FE00000000FE00000000FE00000000FE00000
000FE00000000FE07F00000FE1FFC0000FE787E0000FEE03F0000FF803F0000FF803F8000FF003
F8000FF003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE0
03F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000F
E003F8000FE003F800FFFE3FFF80FFFE3FFF80FFFE3FFF80212A7DA926>I<07000FC01FE03FE0
3FE03FE01FE00FC007000000000000000000000000000000FFE0FFE0FFE00FE00FE00FE00FE00F
E00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE0FFFEFFFEFFFE
0F2B7DAA14>I<FFE00000FFE00000FFE000000FE000000FE000000FE000000FE000000FE00000
0FE000000FE000000FE000000FE000000FE000000FE000000FE000000FE01FFC0FE01FFC0FE01F
FC0FE007800FE00F000FE01E000FE03C000FE078000FE0E0000FE3C0000FE7C0000FEFE0000FFF
E0000FFFF0000FF3F8000FE3F8000FC1FC000FC0FE000FC07F000FC07F000FC03F800FC01FC00F
C00FC00FC00FE0FFFC3FFEFFFC3FFEFFFC3FFE1F2A7EA924>107 D<FFE0FFE0FFE00FE00FE00F
E00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE0
0FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE00FE0FFFEFFFEFFFE0F2A7DA914
>I<FFC07F800FF000FFC1FFE03FFC00FFC383F0707E000FC603F8C07F000FCC01F9803F000FD8
01FF003F800FF001FE003F800FF001FE003F800FE001FC003F800FE001FC003F800FE001FC003F
800FE001FC003F800FE001FC003F800FE001FC003F800FE001FC003F800FE001FC003F800FE001
FC003F800FE001FC003F800FE001FC003F800FE001FC003F800FE001FC003F800FE001FC003F80
0FE001FC003F800FE001FC003F80FFFE1FFFC3FFF8FFFE1FFFC3FFF8FFFE1FFFC3FFF8351B7D9A
3A>I<FFC07F0000FFC1FFC000FFC787E0000FCE03F0000FD803F0000FD803F8000FF003F8000F
F003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F800
0FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8
000FE003F800FFFE3FFF80FFFE3FFF80FFFE3FFF80211B7D9A26>I<003FE00001FFFC0003F07E
000FC01F801F800FC03F800FE03F0007E07F0007F07F0007F07F0007F0FF0007F8FF0007F8FF00
07F8FF0007F8FF0007F8FF0007F8FF0007F8FF0007F87F0007F07F0007F03F800FE03F800FE01F
800FC00FC01F8007F07F0001FFFC00003FE0001D1B7E9A22>I<FFE1FE0000FFE7FF8000FFFE07
E0000FF803F0000FF001F8000FE000FC000FE000FE000FE000FF000FE0007F000FE0007F000FE0
007F800FE0007F800FE0007F800FE0007F800FE0007F800FE0007F800FE0007F800FE0007F000F
E000FF000FE000FF000FE000FE000FE001FC000FF001F8000FF803F0000FFE0FE0000FE7FF8000
0FE1FC00000FE00000000FE00000000FE00000000FE00000000FE00000000FE00000000FE00000
000FE00000000FE0000000FFFE000000FFFE000000FFFE00000021277E9A26>I<FFC1F0FFC7FC
FFCE3E0FD87F0FD87F0FF07F0FF03E0FF01C0FE0000FE0000FE0000FE0000FE0000FE0000FE000
0FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE0000FE000FFFF00FFFF00FFFF00181B7E
9A1C>114 D<03FE300FFFF01E03F03800F0700070F00070F00070F80070FC0000FFE0007FFE00
7FFF803FFFE01FFFF007FFF800FFF80003FC0000FC60007CE0003CF0003CF00038F80038FC0070
FF01E0F7FFC0C1FF00161B7E9A1B>I<00700000700000700000700000F00000F00000F00001F0
0003F00003F00007F0001FFFF0FFFFF0FFFFF007F00007F00007F00007F00007F00007F00007F0
0007F00007F00007F00007F00007F00007F00007F03807F03807F03807F03807F03807F03803F0
3803F87001F86000FFC0001F8015267FA51B>I<FFE03FF800FFE03FF800FFE03FF8000FE003F8
000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003
F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE003F8000FE0
03F8000FE003F8000FE007F80007E007F80007E00FF80003F03BFF8001FFF3FF80003FC3FF8021
1B7D9A26>I<FFFE03FF80FFFE03FF80FFFE03FF8007F000700007F000700007F800F00003F800
E00003FC01E00001FC01C00001FC01C00000FE03800000FE038000007F070000007F070000007F
8F0000003F8E0000003FDE0000001FDC0000001FDC0000000FF80000000FF80000000FF8000000
07F000000007F000000003E000000003E000000001C00000211B7F9A24>I<FFFE7FFC0FFEFFFE
7FFC0FFEFFFE7FFC0FFE0FE007E000E007F003F001C007F003F001C007F807F803C003F807F803
8003F807F8038001FC0EFC070001FC0EFC070001FE1EFC0F0000FE1C7E0E0000FE1C7E0E0000FF
383F1E00007F383F1C00007F783F3C00003FF01FB800003FF01FB800003FF01FF800001FE00FF0
00001FE00FF000000FC007E000000FC007E000000FC007E00000078003C00000078003C0002F1B
7F9A32>I<FFFC0FFF00FFFC0FFF00FFFC0FFF0007F003C00003F807800001FC07800000FE0F00
0000FF1E0000007F3C0000003FF80000001FF00000000FF00000000FF000000007F000000007F8
0000000FFC0000001FFE0000001EFE0000003C7F000000783F800000F01FC00001E01FE00001C0
0FE00003C007F000FFF01FFF80FFF01FFF80FFF01FFF80211B7F9A24>I<FFFE03FF80FFFE03FF
80FFFE03FF8007F000700007F000700007F800F00003F800E00003FC01E00001FC01C00001FC01
C00000FE03800000FE038000007F070000007F070000007F8F0000003F8E0000003FDE0000001F
DC0000001FDC0000000FF80000000FF80000000FF800000007F000000007F000000003E0000000
03E000000001C000000001C000000003800000000380000038078000007C07000000FE0F000000
FE0E000000FE1E000000FE3C0000007C780000003FE00000000FC000000021277F9A24>I
E /Fk 70 124 df<00FC000182000703000607000E02000E00000E00000E00000E00000E0000FF
FF000E07000E07000E07000E07000E07000E07000E07000E07000E07000E07000E07000E07000E
07000E07007F0FE0131A809915>12 D<007E1F8001C170400703C060060380E00E0380400E0380
000E0380000E0380000E0380000E038000FFFFFFE00E0380E00E0380E00E0380E00E0380E00E03
80E00E0380E00E0380E00E0380E00E0380E00E0380E00E0380E00E0380E00E0380E00E0380E07F
8FE3FC1E1A809920>14 D<60C0F1E0F9F068D0081008100810102010202040C1800C0B7F9913>
34 D<60F0F868080808101020C0050B7D990B>39 D<00800100020004000C0008001800300030
0030006000600060006000E000E000E000E000E000E000E000E000E000E0006000600060006000
300030003000180008000C00040002000100008009267D9B0F>I<800040002000100018000800
0C0006000600060003000300030003000380038003800380038003800380038003800380030003
00030003000600060006000C0008001800100020004000800009267E9B0F>I<60F0F070101010
20204080040B7D830B>44 D<FFC0FFC00A0280880D>I<60F0F06004047D830B>I<000C000C001C
0018001800380030003000700060006000E000C000C001C001800180038003000700060006000E
000C000C001C0018001800380030003000700060006000E000C000C0000E257E9B13>I<078018
603030303060186018E01CE01CE01CE01CE01CE01CE01CE01CE01CE01CE01CE01C601860187038
3030186007800E187E9713>I<03000700FF000700070007000700070007000700070007000700
0700070007000700070007000700070007000700FFF00C187D9713>I<0F80106020304038803C
C01CE01C401C003C003800380070006000C001800100020004040804100430083FF87FF8FFF80E
187E9713>I<0F8010E02070607870382038007800700070006000C00F8000E000700038003C00
3CE03CE03CC03C4038407030E00F800E187E9713>I<30183FF03FE03FC0200020002000200020
0027C03860203000380018001C001C401CE01CE01C80184038403030E00F800E187E9713>53
D<01E006100C1818383038300070006000E000E7C0E860F030F018E018E01CE01CE01C601C601C
701830183030186007C00E187E9713>I<40007FFE7FFC7FFC4008801080108020004000400080
018001800100030003000300030007000700070007000700070002000F197E9813>I<07801860
303070306018E018E018E01CE01CE01C601C603C303C185C0F9C001C0018001800387030706060
4021801F000E187E9713>57 D<60F0F060000000000000000060F0F0701010102020408004177D
8F0B>59 D<000C0000000C0000000C0000001E0000001E0000003F000000270000002700000043
800000438000004380000081C0000081C0000081C0000100E0000100E00001FFE0000200700002
00700006007800040038000400380008001C0008001C001C001E00FF00FFC01A1A7F991D>65
D<FFFF000E01C00E00E00E00700E00780E00780E00780E00780E00780E00F00E00E00E03C00FFF
800E01E00E00700E00780E003C0E003C0E003C0E003C0E003C0E00380E00780E00F00E01E0FFFF
80161A7E991B>I<003F0201C0C603002E0E001E1C000E1C0006380006780002700002700002F0
0000F00000F00000F00000F00000F000007000027000027800023800041C00041C00080E000803
003001C0C0003F00171A7E991C>I<FFFF000E01C00E00E00E00300E00380E001C0E001C0E000E
0E000E0E000F0E000F0E000F0E000F0E000F0E000F0E000F0E000F0E000E0E000E0E001E0E001C
0E00380E00380E00700E01C0FFFF00181A7E991D>I<FFFFF00E00700E00300E00100E00180E00
080E00080E00080E04000E04000E04000E0C000FFC000E0C000E04000E04000E04000E00040E00
040E00080E00080E00080E00180E00380E0070FFFFF0161A7E991A>I<FFFFE00E00E00E00600E
00200E00300E00100E00100E00100E04000E04000E04000E0C000FFC000E0C000E04000E04000E
04000E00000E00000E00000E00000E00000E00000E00000E0000FFF000141A7E9919>I<003F02
0001C0C60003002E000E001E001C000E001C00060038000600780002007000020070000200F000
0000F0000000F0000000F0000000F0000000F001FFC070000E0070000E0078000E0038000E001C
000E001C000E000E000E000300160001C06600003F82001A1A7E991E>I<FFE7FF0E00700E0070
0E00700E00700E00700E00700E00700E00700E00700E00700E00700FFFF00E00700E00700E0070
0E00700E00700E00700E00700E00700E00700E00700E00700E0070FFE7FF181A7E991D>I<FFE0
0E000E000E000E000E000E000E000E000E000E000E000E000E000E000E000E000E000E000E000E
000E000E000E000E00FFE00B1A7F990E>I<FFF0000E00000E00000E00000E00000E00000E0000
0E00000E00000E00000E00000E00000E00000E00000E00000E00000E00000E00200E00200E0020
0E00600E00400E00400E00C00E03C0FFFFC0131A7E9918>76 D<FF0003FC0F0003C00F0003C00B
8005C00B8005C00B8005C009C009C009C009C009C009C008E011C008E011C008E011C0087021C0
087021C0083841C0083841C0083841C0081C81C0081C81C0081C81C0080F01C0080F01C0080F01
C0080601C01C0601C0FF861FFC1E1A7E9923>I<FE01FF0F00380F00100B80100B801009C01008
E01008E010087010087010083810081C10081C10080E10080E100807100803900803900801D008
01D00800F00800700800700800301C0030FF8010181A7E991D>I<007F000001C1C00007007000
0E0038001C001C003C001E0038000E0078000F0070000700F0000780F0000780F0000780F00007
80F0000780F0000780F0000780F000078078000F0078000F0038000E003C001E001C001C000E00
38000700700001C1C000007F0000191A7E991E>I<FFFF000E03C00E00E00E00700E00700E0078
0E00780E00780E00780E00700E00700E00E00E03C00FFF000E00000E00000E00000E00000E0000
0E00000E00000E00000E00000E00000E0000FFE000151A7E991A>I<FFFC00000E0780000E01C0
000E00E0000E00F0000E00F0000E00F0000E00F0000E00F0000E00E0000E01C0000E0780000FFC
00000E0600000E0300000E0180000E01C0000E01C0000E01C0000E01E0000E01E0000E01E0000E
01E0800E00F0800E007100FFE03E00191A7E991C>82 D<0FC21836200E6006C006C002C002C002
E00070007E003FE01FF807FC003E000E00070003800380038003C002C006E004D81887E0101A7E
9915>I<7FFFFF00701C0700401C0100401C0100C01C0180801C0080801C0080801C0080001C00
00001C0000001C0000001C0000001C0000001C0000001C0000001C0000001C0000001C0000001C
0000001C0000001C0000001C0000001C0000001C0000001C000003FFE000191A7F991C>I<FFE1
FF0E00380E00100E00100E00100E00100E00100E00100E00100E00100E00100E00100E00100E00
100E00100E00100E00100E00100E00100E001006002007002003004001804000C180003E00181A
7E991D>I<FF801FC01E000F001C0006000E0004000E0004000700080007000800070008000380
10000380100003C0300001C0200001C0200000E0400000E0400000E04000007080000070800000
3900000039000000390000001E0000001E0000001E0000000C0000000C00001A1A7F991D>I<FF
83FF0FF03C007801C01C007800801C007800800E007801000E007801000E009C010007009C0200
07009C020007010E020007010E020003810E04000382070400038207040001C207080001C40388
0001C403880000E403900000E403900000E801D000007801E000007801E000007000E000007000
E000003000C0000020004000241A7F9927>I<FF801FE01E0007000E0006000F00040007000800
0780080003C0100001C0300001E0200000F04000007040000078800000388000001D0000001F00
00000E0000000E0000000E0000000E0000000E0000000E0000000E0000000E0000000E0000000E
000000FFE0001B1A7F991D>89 D<FEFEC0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0
C0C0C0C0C0C0C0C0C0C0FEFE07257D9B0B>91 D<1830204040804080810081008100B160F9F078
F030600C0B7B9913>I<FEFE060606060606060606060606060606060606060606060606060606
060606060606FEFE0725809B0B>I<3F8070C070E020700070007007F01C7030707070E070E071
E071E0F171FB1E3C10107E8F13>97 D<FC00001C00001C00001C00001C00001C00001C00001C00
001C00001C00001CF8001F0E001E07001C03801C01801C01C01C01C01C01C01C01C01C01C01C01
C01C03801C03001E07001B0C0010F000121A7F9915>I<07F80C1C381C30087000E000E000E000
E000E000E0007000300438080C1807E00E107F8F11>I<007E00000E00000E00000E00000E0000
0E00000E00000E00000E00000E0003CE000C3E00380E00300E00700E00E00E00E00E00E00E00E0
0E00E00E00E00E00600E00700E00381E001C2E0007CFC0121A7F9915>I<07C01C303018701860
0CE00CFFFCE000E000E000E0006000300438080C1807E00E107F8F11>I<01F0031807380E100E
000E000E000E000E000E00FFC00E000E000E000E000E000E000E000E000E000E000E000E000E00
0E007FE00D1A80990C>I<0FCE187330307038703870387038303018602FC02000600070003FF0
3FFC1FFE600FC003C003C003C0036006381C07E010187F8F13>I<FC00001C00001C00001C0000
1C00001C00001C00001C00001C00001C00001CF8001D0C001E0E001E0E001C0E001C0E001C0E00
1C0E001C0E001C0E001C0E001C0E001C0E001C0E001C0E00FF9FC0121A7F9915>I<18003C003C
001800000000000000000000000000FC001C001C001C001C001C001C001C001C001C001C001C00
1C001C001C00FF80091A80990B>I<018003C003C001800000000000000000000000000FC001C0
01C001C001C001C001C001C001C001C001C001C001C001C001C001C001C001C001C041C0E180E3
007E000A2182990C>I<FC00001C00001C00001C00001C00001C00001C00001C00001C00001C00
001C3F801C1E001C18001C10001C20001C40001DC0001FE0001CE0001C70001C78001C38001C1C
001C1E001C1F00FF3FC0121A7F9914>I<FC001C001C001C001C001C001C001C001C001C001C00
1C001C001C001C001C001C001C001C001C001C001C001C001C001C00FF80091A80990B>I<FC7C
1F001D8E63801E0781C01E0781C01C0701C01C0701C01C0701C01C0701C01C0701C01C0701C01C
0701C01C0701C01C0701C01C0701C01C0701C0FF9FE7F81D107F8F20>I<FCF8001D0C001E0E00
1E0E001C0E001C0E001C0E001C0E001C0E001C0E001C0E001C0E001C0E001C0E001C0E00FF9FC0
12107F8F15>I<07E01C38300C700E6006E007E007E007E007E007E0076006700E381C1C3807E0
10107F8F13>I<FCF8001F0E001E07001C03801C03801C01C01C01C01C01C01C01C01C01C01C01
C01C03801C03001E07001F0C001CF0001C00001C00001C00001C00001C00001C0000FF80001217
7F8F15>I<03C2000C2600381E00300E00700E00E00E00E00E00E00E00E00E00E00E00E00E0070
0E00700E00381E001C2E0007CE00000E00000E00000E00000E00000E00000E00007FC012177F8F
14>I<FCE01D701E701E201C001C001C001C001C001C001C001C001C001C001C00FFC00C107F8F
0F>I<1F2060E04020C020C020F0007F003FC01FE000F080708030C030C020F0408F800C107F8F
0F>I<0400040004000C000C001C003C00FFC01C001C001C001C001C001C001C001C001C201C20
1C201C201C200E4003800B177F960F>I<FC7E001C0E001C0E001C0E001C0E001C0E001C0E001C
0E001C0E001C0E001C0E001C0E001C0E001C1E000C2E0007CFC012107F8F15>I<FF1F803C0600
1C04001C04001E0C000E08000E080007100007100007900003A00003A00001C00001C00001C000
00800011107F8F14>I<FF3F9F803C0E0700380E06001C1604001C1704001E170C000E2308000E
2388000F239800074190000741D00003C1E0000380E0000380E0000180C0000100400019107F8F
1C>I<FF3F803C1C001C18000E100007200007600003C00001C00001E00003E000027000043800
083800181C00381E00FC3FC012107F8F14>I<FF1F803C06001C04001C04001E0C000E08000E08
0007100007100007900003A00003A00001C00001C00001C000008000008000010000010000E100
00E20000E4000078000011177F8F14>I<7FF86070407040E041C041C00380070007000E081C08
1C08381070107030FFF00D107F8F11>I<FFFFC01201808913>I E /Fl 10
58 df<1F00318060C04040C060C060C060C060C060C060C060C060404060C031801F000B107F8F
0F>48 D<0C003C00CC000C000C000C000C000C000C000C000C000C000C000C000C00FF8009107E
8F0F>I<1F00618040C08060C0600060006000C00180030006000C00102020207FC0FFC00B107F
8F0F>I<1F00218060C060C000C0008001800F00008000400060C060C060804060801F000B107F
8F0F>I<0300030007000F000B001300330023004300C300FFE003000300030003001FE00B107F
8F0F>I<20803F002C002000200020002F0030802040006000600060C06080C061801F000B107F
8F0F>I<0780184030C060C06000C000CF00F080E040C060C060C060406060C030801F000B107F
8F0F>I<40007FE07FC08080808001000200040004000C0008000800180018001800180018000B
117E900F>I<1F00208040404040404070803F000F00338061C0C060C060C060404060801F000B
107F8F0F>I<1F00318060C0C040C060C060C06040E021E01E600060004060C0608043003E000B
107F8F0F>I E /Fm 4 119 df<03CC063C0C3C181C3838303870387038E070E070E070E070E0E2
C0E2C0E261E462643C380F127B9115>97 D<01800380010000000000000000000000000000001C
002600470047008E008E000E001C001C001C0038003800710071007100720072003C00091C7C9B
0D>105 D<01F006080C080C1C18181C001F001FC00FF007F0007800386030E030C030806060C0
1F000E127D9111>115 D<1E06270E470E4706870287020E020E021C041C041C041C0818083808
181018200C4007800F127C9113>118 D E /Fn 32 123 df<007FC001C1C00303C00703C00E01
C00E01C00E01C00E01C00E01C00E01C00E01C0FFFFC00E01C00E01C00E01C00E01C00E01C00E01
C00E01C00E01C00E01C00E01C00E01C00E01C00E01C00E01C00E01C00E01C07FCFF8151D809C17
>13 D<60F0F0701010101020204080040C7C830C>44 D<FFE0FFE00B0280890E>I<60F0F06004
047C830C>I<000600000006000000060000000F0000000F0000000F0000001780000017800000
1780000023C0000023C0000023C0000041E0000041E0000041E0000080F0000080F0000180F800
0100780001FFF80003007C0002003C0002003C0006003E0004001E0004001E000C001F001E001F
00FF80FFF01C1D7F9C1F>65 D<001F808000E0618001801980070007800E0003801C0003801C00
018038000180780000807800008070000080F0000000F0000000F0000000F0000000F0000000F0
000000F0000000F0000000700000807800008078000080380000801C0001001C0001000E000200
070004000180080000E03000001FC000191E7E9C1E>67 D<003F800000E0E0000380380007001C
000E000E001C0007003C00078038000380780003C0780003C0700001C0F00001E0F00001E0F000
01E0F00001E0F00001E0F00001E0F00001E0F00001E0700001C0780003C0780003C0380003803C
0007801C0007000E000E0007001C000380380000E0E000003F80001B1E7E9C20>79
D<7FFFFFC0700F01C0600F00C0400F0040400F0040C00F0020800F0020800F0020800F0020000F
0000000F0000000F0000000F0000000F0000000F0000000F0000000F0000000F0000000F000000
0F0000000F0000000F0000000F0000000F0000000F0000000F0000001F800003FFFC001B1C7F9B
1E>84 D<1FC000307000783800781C00301C00001C00001C0001FC000F1C00381C00701C00601C
00E01C40E01C40E01C40603C40304E801F870012127E9115>97 D<FC00001C00001C00001C0000
1C00001C00001C00001C00001C00001C00001C00001C7C001D86001E03001C01801C01C01C00C0
1C00E01C00E01C00E01C00E01C00E01C00E01C00C01C01C01C01801E030019060010F800131D7F
9C17>I<07E00C301878307870306000E000E000E000E000E000E00060007004300418080C3007
C00E127E9112>I<003F0000070000070000070000070000070000070000070000070000070000
070003E7000C1700180F00300700700700600700E00700E00700E00700E00700E00700E0070060
0700700700300700180F000C370007C7E0131D7E9C17>I<03E00C301818300C700E6006E006FF
FEE000E000E000E00060007002300218040C1803E00F127F9112>I<00F8018C071E061E0E0C0E
000E000E000E000E000E00FFE00E000E000E000E000E000E000E000E000E000E000E000E000E00
0E000E000E007FE00F1D809C0D>I<00038003C4C00C38C01C3880181800381C00381C00381C00
381C001818001C38000C300013C0001000003000001800001FF8001FFF001FFF803003806001C0
C000C0C000C0C000C06001803003001C0E0007F800121C7F9215>I<FC00001C00001C00001C00
001C00001C00001C00001C00001C00001C00001C00001C7C001C87001D03001E03801C03801C03
801C03801C03801C03801C03801C03801C03801C03801C03801C03801C03801C0380FF9FF0141D
7F9C17>I<18003C003C0018000000000000000000000000000000FC001C001C001C001C001C00
1C001C001C001C001C001C001C001C001C001C001C00FF80091D7F9C0C>I<FC00001C00001C00
001C00001C00001C00001C00001C00001C00001C00001C00001C3FC01C0F001C0C001C08001C10
001C20001C40001CE0001DE0001E70001C78001C38001C3C001C1C001C0E001C0F001C0F80FF9F
E0131D7F9C16>107 D<FC001C001C001C001C001C001C001C001C001C001C001C001C001C001C
001C001C001C001C001C001C001C001C001C001C001C001C001C00FF80091D7F9C0C>I<FC7E07
E0001C838838001D019018001E01E01C001C01C01C001C01C01C001C01C01C001C01C01C001C01
C01C001C01C01C001C01C01C001C01C01C001C01C01C001C01C01C001C01C01C001C01C01C001C
01C01C00FF8FF8FF8021127F9124>I<FC7C001C87001D03001E03801C03801C03801C03801C03
801C03801C03801C03801C03801C03801C03801C03801C03801C0380FF9FF014127F9117>I<03
F0000E1C00180600300300700380600180E001C0E001C0E001C0E001C0E001C0E001C060018070
03803003001806000E1C0003F00012127F9115>I<FC7C001D86001E03001C01801C01C01C00C0
1C00E01C00E01C00E01C00E01C00E01C00E01C01C01C01C01C01801E03001D06001CF8001C0000
1C00001C00001C00001C00001C00001C0000FF8000131A7F9117>I<03C1000C3300180B00300F
00700700700700E00700E00700E00700E00700E00700E00700600700700700300F00180F000C37
0007C700000700000700000700000700000700000700000700003FE0131A7E9116>I<FCE01D30
1E781E781C301C001C001C001C001C001C001C001C001C001C001C001C00FFC00D127F9110>I<
1F9030704030C010C010E010F8007F803FE00FF000F880388018C018C018E010D0608FC00D127F
9110>I<04000400040004000C000C001C003C00FFE01C001C001C001C001C001C001C001C001C
001C101C101C101C101C100C100E2003C00C1A7F9910>I<FC1F801C03801C03801C03801C0380
1C03801C03801C03801C03801C03801C03801C03801C03801C03801C07800C07800E1B8003E3F0
14127F9117>I<FF07E03C03801C01001C01000E02000E02000704000704000704000388000388
0003D80001D00001D00000E00000E00000E00000400013127F9116>I<FF3FCFE03C0F03801C07
01801C0701001C0B01000E0B82000E0B82000E1182000711C4000711C4000720C40003A0E80003
A0E80003C0680001C0700001C0700001803000008020001B127F911E>I<FF07E03C03801C0100
1C01000E02000E020007040007040007040003880003880003D80001D00001D00000E00000E000
00E000004000004000008000008000F08000F10000F300006600003C0000131A7F9116>121
D<7FFC70386038407040F040E041C003C0038007000F040E041C043C0C380870087038FFF80E12
7F9112>I E /Fo 14 122 df<78FCFCFCFC7800000000000078FCFCFCFC7806127D910D>58
D<00038000000380000007C0000007C0000007C000000FE000000FE000001FF000001BF000001B
F0000031F8000031F8000061FC000060FC0000E0FE0000C07E0000C07E0001803F0001FFFF0003
FFFF8003001F8003001F8006000FC006000FC00E000FE00C0007E0FFC07FFEFFC07FFE1F1C7E9B
24>65 D<FFFC07FFFFFC07FF0FC000E00FC001C00FC003800FC006000FC00C000FC038000FC070
000FC0E0000FC1C0000FC3C0000FC7E0000FCFE0000FFBF0000FF3F8000FE1F8000FC0FC000FC0
FE000FC07E000FC03F000FC01F800FC01FC00FC00FC00FC007E00FC007F0FFFC3FFFFFFC3FFF20
1C7E9B25>75 D<FFFC7FFE0FFCFFFC7FFE0FFC0FC007E000C00FC007F000C00FE003F001C007E0
03F0018007E007F8018003F007F8030003F007F8030003F80CFC070001F80CFC060001F81CFE06
0001FC187E0E0000FC187E0C0000FC387F0C00007E303F1800007E303F1800007F601FB800003F
601FB000003FE01FF000003FC00FF000001FC00FE000001FC00FE000000F8007C000000F8007C0
00000F0003C0000007000380000007000380002E1C7F9B31>87 D<0FF8001C1E003E0F803E0780
3E07C01C07C00007C0007FC007E7C01F07C03C07C07C07C0F807C0F807C0F807C0780BC03E13F8
0FE1F815127F9117>97 D<FF0000FF00001F00001F00001F00001F00001F00001F00001F00001F
00001F00001F3F801FE1E01F80701F00781F003C1F003C1F003E1F003E1F003E1F003E1F003E1F
003E1F003C1F003C1F00781F80701EC1E01C3F00171D7F9C1B>I<03FC000E0E001C1F003C1F00
781F00780E00F80000F80000F80000F80000F80000F800007800007801803C01801C03000E0E00
03F80011127E9115>I<000FF0000FF00001F00001F00001F00001F00001F00001F00001F00001
F00001F001F9F00F07F01C03F03C01F07801F07801F0F801F0F801F0F801F0F801F0F801F0F801
F07801F07801F03C01F01C03F00F0FFE03F9FE171D7E9C1B>I<01FC000F07001C03803C01C078
01C07801E0F801E0F801E0FFFFE0F80000F80000F800007800007C00603C00601E00C00F038001
FC0013127F9116>I<01FC000F07801C01C03C01E07800F07800F0F800F8F800F8F800F8F800F8
F800F8F800F87800F07800F03C01E01E03C00F078001FC0015127F9118>111
D<FE3E00FE47001E8F801E8F801E8F801F07001F00001F00001F00001F00001F00001F00001F00
001F00001F00001F0000FFF000FFF00011127F9114>114 D<1FD830786018E018E018F000FF80
7FE07FF01FF807FC007CC01CC01CE01CE018F830CFC00E127E9113>I<03000300030003000700
07000F000F003FFCFFFC1F001F001F001F001F001F001F001F001F001F0C1F0C1F0C1F0C0F0807
9803F00E1A7F9913>I<FFC1FCFFC1FC1F00601F80E00F80C00FC0C007C18007C18003E30003E3
0001F70001F60000FE0000FC0000FC00007800007800003000003000007000706000F86000F8C0
00F980007300003E0000161A7F9119>121 D E /Fp 84 124 df<001F83E000F06E3001C07878
0380F8780300F03007007000070070000700700007007000070070000700700007007000FFFFFF
800700700007007000070070000700700007007000070070000700700007007000070070000700
700007007000070070000700700007007000070070000700700007007000070070007FE3FF001D
20809F1B>11 D<003F0000E0C001C0C00381E00701E00701E00700000700000700000700000700
00070000FFFFE00700E00700E00700E00700E00700E00700E00700E00700E00700E00700E00700
E00700E00700E00700E00700E00700E00700E00700E07FC3FE1720809F19>I<003FE000E0E001
C1E00381E00700E00700E00700E00700E00700E00700E00700E00700E0FFFFE00700E00700E007
00E00700E00700E00700E00700E00700E00700E00700E00700E00700E00700E00700E00700E007
00E00700E00700E07FE7FE1720809F19>I<001F81F80000F04F040001C07C06000380F80F0003
00F00F000700F00F00070070000007007000000700700000070070000007007000000700700000
FFFFFFFF0007007007000700700700070070070007007007000700700700070070070007007007
000700700700070070070007007007000700700700070070070007007007000700700700070070
07000700700700070070070007007007007FE3FE3FF02420809F26>I<70F8F8F8F8F8F8F87070
70707070707070702020202020000000000070F8F8F87005217CA00D>33
D<7038F87CFC7EFC7E743A0402040204020804080410081008201040200F0E7E9F17>I<70F8FC
FC74040404080810102040060E7C9F0D>39 D<0020004000800100020006000C000C0018001800
3000300030007000600060006000E000E000E000E000E000E000E000E000E000E000E000E00060
00600060007000300030003000180018000C000C000600020001000080004000200B2E7DA112>
I<800040002000100008000C00060006000300030001800180018001C000C000C000C000E000E0
00E000E000E000E000E000E000E000E000E000E000C000C000C001C00180018001800300030006
0006000C00080010002000400080000B2E7DA112>I<0006000000060000000600000006000000
060000000600000006000000060000000600000006000000060000000600000006000000060000
00060000FFFFFFF0FFFFFFF0000600000006000000060000000600000006000000060000000600
0000060000000600000006000000060000000600000006000000060000000600001C207D9A23>
43 D<70F8FCFC74040404080810102040060E7C840D>I<FFC0FFC00A027F8A0F>I<70F8F8F870
05057C840D>I<00030003000700060006000E000C000C001C0018001800380030003000700060
006000E000C000C001C00180018001800380030003000700060006000E000C000C001C00180018
00380030003000700060006000E000C000C000102D7DA117>I<03F0000E1C001C0E0018060038
0700700380700380700380700380F003C0F003C0F003C0F003C0F003C0F003C0F003C0F003C0F0
03C0F003C0F003C0F003C0F003C07003807003807003807807803807001806001C0E000E1C0003
F000121F7E9D17>I<018003800F80F38003800380038003800380038003800380038003800380
038003800380038003800380038003800380038003800380038007C0FFFE0F1E7C9D17>I<03F0
000C1C00100E00200700400780800780F007C0F803C0F803C0F803C02007C00007C00007800007
80000F00000E00001C0000380000700000600000C0000180000300000600400C00401800401000
803FFF807FFF80FFFF80121E7E9D17>I<03F0000C1C00100E00200F00780F8078078078078038
0F80000F80000F00000F00000E00001C0000380003F000003C00000E00000F0000078000078000
07C02007C0F807C0F807C0F807C0F00780400780400F00200E001C3C0003F000121F7E9D17>I<
000600000600000E00000E00001E00002E00002E00004E00008E00008E00010E00020E00020E00
040E00080E00080E00100E00200E00200E00400E00C00E00FFFFF0000E00000E00000E00000E00
000E00000E00000E0000FFE0141E7F9D17>I<1803001FFE001FFC001FF8001FE0001000001000
0010000010000010000010000011F000161C00180E001007001007800003800003800003C00003
C00003C07003C0F003C0F003C0E00380400380400700200600100E000C380003E000121F7E9D17
>I<007C000182000701000E03800C07801C0780380300380000780000700000700000F1F000F2
1C00F40600F80700F80380F80380F003C0F003C0F003C0F003C0F003C07003C07003C070038038
03803807001807000C0E00061C0001F000121F7E9D17>I<4000007FFFC07FFF807FFF80400100
80020080020080040000080000080000100000200000200000400000400000C00000C00001C000
018000038000038000038000038000078000078000078000078000078000078000078000030000
121F7D9D17>I<03F0000C0C001006003003002001806001806001806001807001807803003E03
003F06001FC8000FF00003F80007FC000C7E00103F00300F806003804001C0C001C0C000C0C000
C0C000C0C000806001802001001002000C0C0003F000121F7E9D17>I<03F0000E18001C0C0038
0600380700700700700380F00380F00380F003C0F003C0F003C0F003C0F003C07007C07007C038
07C0180BC00E13C003E3C0000380000380000380000700300700780600780E00700C0020180010
70000FC000121F7E9D17>I<70F8F8F8700000000000000000000070F8F8F87005147C930D>I<70
F8F8F8700000000000000000000070F0F8F878080808101010202040051D7C930D>I<7FFFFFE0
FFFFFFF00000000000000000000000000000000000000000000000000000000000000000FFFFFF
F07FFFFFE01C0C7D9023>61 D<001F800000E0700001000800060006000800010008000100100F
00802030C0402060404040C0202041C01C2041C01C2081801C1083801C1083801C1083801C1083
801C1083801C1083801C1081801C1041C01C1041C01C1040C03C2020605C202030CC40100F0780
080000000800000006000070010001C000E01F00001FF0001C207D9F23>64
D<000100000003800000038000000380000007C0000007C0000007C0000009E0000009E0000009
E0000010F0000010F0000010F00000207800002078000020780000403C0000403C0000403C0000
801E0000801E0000FFFE0001000F0001000F0001000F00020007800200078002000780040003C0
0E0003C01F0007E0FFC03FFE1F207F9F22>I<FFFFE0000F80380007801E0007801F0007800F00
07800F8007800F8007800F8007800F8007800F8007800F0007801F0007801E0007803C0007FFF0
0007803C0007801E0007800F0007800F8007800780078007C0078007C0078007C0078007C00780
07C00780078007800F8007800F0007801F000F803C00FFFFF0001A1F7E9E20>I<000FC0400070
30C001C009C0038005C0070003C00E0001C01E0000C01C0000C03C0000C07C0000407C00004078
000040F8000000F8000000F8000000F8000000F8000000F8000000F8000000F8000000F8000000
780000007C0000407C0000403C0000401C0000401E0000800E000080070001000380020001C004
0000703800000FC0001A217D9F21>I<FFFFE0000F803C0007801E000780070007800380078003
C0078001E0078001E0078001F0078000F0078000F0078000F8078000F8078000F8078000F80780
00F8078000F8078000F8078000F8078000F8078000F0078000F0078000F0078001E0078001E007
8003C0078003800780070007800E000F803C00FFFFE0001D1F7E9E23>I<FFFFFF000F800F0007
800300078003000780010007800180078000800780008007800080078080800780800007808000
078080000781800007FF8000078180000780800007808000078080000780800007800020078000
2007800020078000400780004007800040078000C0078000C0078001800F800F80FFFFFF801B1F
7E9E1F>I<FFFFFF000F800F000780030007800300078001000780018007800080078000800780
008007800080078080000780800007808000078080000781800007FF8000078180000780800007
808000078080000780800007800000078000000780000007800000078000000780000007800000
078000000FC00000FFFE0000191F7E9E1E>I<000FE0200078186000E004E0038002E0070001E0
0F0000E01E0000601E0000603C0000603C0000207C00002078000020F8000000F8000000F80000
00F8000000F8000000F8000000F8000000F8007FFCF80003E0780001E07C0001E03C0001E03C00
01E01E0001E01E0001E00F0001E0070001E0038002E000E0046000781820000FE0001E217D9F24
>I<FFF8FFF80F800F8007800F0007800F0007800F0007800F0007800F0007800F0007800F0007
800F0007800F0007800F0007800F0007800F0007FFFF0007800F0007800F0007800F0007800F00
07800F0007800F0007800F0007800F0007800F0007800F0007800F0007800F0007800F0007800F
000F800F80FFF8FFF81D1F7E9E22>I<FFFC0FC007800780078007800780078007800780078007
80078007800780078007800780078007800780078007800780078007800780078007800FC0FFFC
0E1F7F9E10>I<0FFFC0007C00003C00003C00003C00003C00003C00003C00003C00003C00003C
00003C00003C00003C00003C00003C00003C00003C00003C00003C00003C00003C00003C00203C
00F83C00F83C00F83C00F0380040780040700030E0000F800012207E9E17>I<FFFC0FFC0FC003
E00780018007800100078002000780040007800800078010000780200007804000078080000781
00000783000007878000078F80000793C0000791E00007A1E00007C0F0000780F0000780780007
803C0007803C0007801E0007801E0007800F000780078007800780078007C00FC007E0FFFC3FFC
1E1F7E9E23>I<FFFE000FC0000780000780000780000780000780000780000780000780000780
000780000780000780000780000780000780000780000780000780000780020780020780020780
0207800607800407800407800C07801C0F807CFFFFFC171F7E9E1C>I<FF80001FF80F80001F80
0780001F0005C0002F0005C0002F0005C0002F0004E0004F0004E0004F000470008F000470008F
000470008F000438010F000438010F000438010F00041C020F00041C020F00041C020F00040E04
0F00040E040F00040E040F000407080F000407080F000407080F000403900F000403900F000401
E00F000401E00F000401E00F000E00C00F001F00C01F80FFE0C1FFF8251F7E9E2A>I<FF803FF8
07C007C007C0038005E0010005E0010004F001000478010004780100043C0100043C0100041E01
00040F0100040F010004078100040781000403C1000401E1000401E1000400F1000400F1000400
790004003D0004003D0004001F0004001F0004000F0004000700040007000E0003001F000300FF
E001001D1F7E9E22>I<001F800000F0F00001C0380007801E000F000F000E0007001E0007803C
0003C03C0003C07C0003E0780001E0780001E0F80001F0F80001F0F80001F0F80001F0F80001F0
F80001F0F80001F0F80001F0F80001F0780001E07C0003E07C0003E03C0003C03C0003C01E0007
800E0007000F000F0007801E0001C0380000F0F000001F80001C217D9F23>I<FFFFE0000F8078
0007801C0007801E0007800F0007800F8007800F8007800F8007800F8007800F8007800F800780
0F0007801E0007801C000780780007FFE000078000000780000007800000078000000780000007
800000078000000780000007800000078000000780000007800000078000000FC00000FFFC0000
191F7E9E1F>I<001F800000F0F00001C0380007801E000F000F000E0007001E0007803C0003C0
3C0003C07C0003E07C0003E0780001E0F80001F0F80001F0F80001F0F80001F0F80001F0F80001
F0F80001F0F80001F0F80001F0780001E0780001E07C0003E03C0003C03C0F03C01E1087800E20
47000F204F0007A03E0001E0380000F0F010001FB01000003010000038300000387000003FF000
001FE000001FE000000FC0000007801C297D9F23>I<FFFF80000F80F0000780780007803C0007
801E0007801E0007801F0007801F0007801F0007801F0007801E0007801E0007803C0007807800
0780F00007FF80000781C0000780E0000780F0000780700007807800078078000780780007807C
0007807C0007807C0007807C0407807E0407803E040FC01E08FFFC0F10000003E01E207E9E21>
I<07E0800C1980100780300380600180600180E00180E00080E00080E00080F00000F000007800
007F00003FF0001FFC000FFE0003FF00001F800007800003C00003C00001C08001C08001C08001
C08001C0C00180C00380E00300F00600CE0C0081F80012217D9F19>I<7FFFFFE0780F01E0600F
0060400F0020400F0020C00F0030800F0010800F0010800F0010800F0010000F0000000F000000
0F0000000F0000000F0000000F0000000F0000000F0000000F0000000F0000000F0000000F0000
000F0000000F0000000F0000000F0000000F0000000F0000000F0000001F800007FFFE001C1F7E
9E21>I<FFFC3FF80FC007C0078003800780010007800100078001000780010007800100078001
000780010007800100078001000780010007800100078001000780010007800100078001000780
01000780010007800100078001000780010007800100038002000380020001C0020001C0040000
E008000070180000382000000FC0001D207E9E22>I<FFF003FE1F8000F80F0000600F80006007
8000400780004003C0008003C0008003C0008001E0010001E0010001F0010000F0020000F00200
00F806000078040000780400003C0800003C0800003C0800001E1000001E1000001F3000000F20
00000F20000007C0000007C0000007C000000380000003800000038000000100001F207F9E22>
I<FFF07FF81FF01F800FC007C00F00078003800F00078001000F0007C00100078007C002000780
07C00200078007C0020003C009E0040003C009E0040003C009E0040003E010F00C0001E010F008
0001E010F0080001F02078080000F02078100000F02078100000F0403C10000078403C20000078
403C20000078C03E2000003C801E4000003C801E4000003C801E4000001F000F8000001F000F80
00001F000F8000001E00078000000E00070000000E00070000000C000300000004000200002C20
7F9E2F>I<7FF83FF80FE00FC007C0070003C0020001E0040001F00C0000F0080000781000007C
1000003C2000003E4000001E4000000F8000000F8000000780000003C0000007E0000005E00000
09F0000018F8000010780000207C0000603C0000401E0000801F0001800F0001000780020007C0
070003C01F8007E0FFE01FFE1F1F7F9E22>I<FFF003FF1F8000F80F8000600780004007C00040
03E0008001E0008001F0010000F0030000F80200007C0400003C0400003E0800001E0800001F10
00000FB0000007A0000007C0000003C0000003C0000003C0000003C0000003C0000003C0000003
C0000003C0000003C0000003C0000003C0000007C000007FFE00201F7F9E22>I<7FFFF87C00F8
7000F06001E04001E0C003C0C003C0800780800F80800F00001E00001E00003C00003C00007800
00F80000F00001E00001E00003C00403C0040780040F80040F000C1E000C1E00083C00183C0018
780038F801F8FFFFF8161F7D9E1C>I<FEFEC0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0
C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0C0FEFE072D7CA10D>I<08041008201020104020
4020804080408040B85CFC7EFC7E7C3E381C0F0E7B9F17>I<FEFE060606060606060606060606
0606060606060606060606060606060606060606060606060606060606FEFE072D7FA10D>I<1F
E000303000781800781C00300E00000E00000E00000E0000FE00078E001E0E00380E00780E00F0
0E10F00E10F00E10F01E10781E103867200F83C014147E9317>97 D<0E0000FE00000E00000E00
000E00000E00000E00000E00000E00000E00000E00000E00000E3E000EC3800F01C00F00E00E00
E00E00700E00700E00780E00780E00780E00780E00780E00780E00700E00700E00E00F00E00D01
C00CC300083E0015207F9F19>I<03F80E0C1C1E381E380C70007000F000F000F000F000F000F0
0070007000380138011C020E0C03F010147E9314>I<000380003F800003800003800003800003
8000038000038000038000038000038000038003E380061B801C07803803803803807003807003
80F00380F00380F00380F00380F00380F003807003807003803803803807801C07800E1B8003E3
F815207E9F19>I<03F0000E1C001C0E00380700380700700700700380F00380F00380FFFF80F0
0000F00000F000007000007000003800801800800C010007060001F80011147F9314>I<007C00
C6018F038F07060700070007000700070007000700FFF007000700070007000700070007000700
07000700070007000700070007000700070007007FF01020809F0E>I<0000E003E3300E3C301C
1C30380E00780F00780F00780F00780F00780F00380E001C1C001E380033E00020000020000030
00003000003FFE001FFF800FFFC03001E0600070C00030C00030C00030C000306000603000C01C
038003FC00141F7F9417>I<0E0000FE00000E00000E00000E00000E00000E00000E00000E0000
0E00000E00000E00000E3E000E43000E81800F01C00F01C00E01C00E01C00E01C00E01C00E01C0
0E01C00E01C00E01C00E01C00E01C00E01C00E01C00E01C00E01C0FFE7FC16207F9F19>I<1C00
1E003E001E001C000000000000000000000000000E007E000E000E000E000E000E000E000E000E
000E000E000E000E000E000E000E000E000E00FFC00A1F809E0D>I<00E001F001F001F000E000
0000000000000000000000007007F000F000700070007000700070007000700070007000700070
00700070007000700070007000700070007000706070F060F0C061803F000C28829E0E>I<0E00
00FE00000E00000E00000E00000E00000E00000E00000E00000E00000E00000E00000E0FF00E03
C00E03000E02000E04000E08000E10000E30000E70000EF8000F38000E1C000E1E000E0E000E07
000E07800E03800E03C00E03E0FFCFF815207F9F18>I<0E00FE000E000E000E000E000E000E00
0E000E000E000E000E000E000E000E000E000E000E000E000E000E000E000E000E000E000E000E
000E000E000E00FFE00B20809F0D>I<0E1F01F000FE618618000E81C81C000F00F00E000F00F0
0E000E00E00E000E00E00E000E00E00E000E00E00E000E00E00E000E00E00E000E00E00E000E00
E00E000E00E00E000E00E00E000E00E00E000E00E00E000E00E00E000E00E00E00FFE7FE7FE023
147F9326>I<0E3E00FE43000E81800F01C00F01C00E01C00E01C00E01C00E01C00E01C00E01C0
0E01C00E01C00E01C00E01C00E01C00E01C00E01C00E01C0FFE7FC16147F9319>I<01F800070E
001C03803801C03801C07000E07000E0F000F0F000F0F000F0F000F0F000F0F000F07000E07000
E03801C03801C01C0380070E0001F80014147F9317>I<0E3E00FEC3800F01C00F00E00E00E00E
00F00E00700E00780E00780E00780E00780E00780E00780E00700E00F00E00E00F01E00F01C00E
C3000E3E000E00000E00000E00000E00000E00000E00000E00000E0000FFE000151D7F9319>I<
03E0800619801C05803C0780380380780380700380F00380F00380F00380F00380F00380F00380
7003807803803803803807801C0B800E138003E380000380000380000380000380000380000380
000380000380003FF8151D7E9318>I<0E78FE8C0F1E0F1E0F0C0E000E000E000E000E000E000E
000E000E000E000E000E000E000E00FFE00F147F9312>I<1F9030704030C010C010C010E00078
007F803FE00FF00070803880188018C018C018E030D0608F800D147E9312>I<02000200020006
0006000E000E003E00FFF80E000E000E000E000E000E000E000E000E000E000E000E080E080E08
0E080E080610031001E00D1C7F9B12>I<0E01C0FE1FC00E01C00E01C00E01C00E01C00E01C00E
01C00E01C00E01C00E01C00E01C00E01C00E01C00E01C00E01C00E03C00603C0030DC001F1FC16
147F9319>I<FF83F81E01E01C00C00E00800E00800E0080070100070100038200038200038200
01C40001C40001EC0000E80000E80000700000700000700000200015147F9318>I<FF9FE1FC3C
0780701C0300601C0380200E0380400E0380400E03C0400707C0800704C0800704E08003886100
0388710003C8730001D0320001D03A0000F03C0000E01C0000E01C0000601800004008001E147F
9321>I<7FC3FC0F01E00701C007018003810001C20000E40000EC00007800003800003C00007C
00004E000087000107000303800201C00601E01E01E0FF07FE1714809318>I<FF83F81E01E01C
00C00E00800E00800E008007010007010003820003820003820001C40001C40001EC0000E80000
E800007000007000007000002000002000004000004000004000F08000F08000F100006200003C
0000151D7F9318>I<3FFF380E200E201C40384078407000E001E001C00380078007010E011E01
1C0338027006700EFFFE10147F9314>I<FFFFFC1601808C17>I E /Fq 10
58 df<07C018303018701C600C600CE00EE00EE00EE00EE00EE00EE00EE00EE00E600C600C701C
30181C7007C00F157F9412>48 D<03000700FF0007000700070007000700070007000700070007
0007000700070007000700070007007FF00C157E9412>I<0F8030E040708030C038E038403800
3800700070006000C00180030006000C08080810183FF07FF0FFF00D157E9412>I<0FE0303060
18701C701C001C00180038006007E000300018000C000E000EE00EE00EC00C401830300FE00F15
7F9412>I<00300030007000F001F001700270047008701870107020704070C070FFFE00700070
00700070007003FE0F157F9412>I<20303FE03FC0240020002000200020002F8030E020700030
003800384038E038E0388030406020C01F000D157E9412>I<01F00608080C181C301C70006000
E000E3E0EC30F018F00CE00EE00EE00E600E600E300C3018183007C00F157F9412>I<40007FFE
7FFC7FF8C008801080200040008000800100010003000200060006000E000E000E000E000E0004
000F167E9512>I<07E018302018600C600C700C78183E101F600FC00FF018F8607C601EC00EC0
06C006C004600C38300FE00F157F9412>I<07C0183030186018E00CE00CE00EE00EE00E601E30
1E186E0F8E000E000C001C70187018603020C01F800F157F9412>I E /Fr
46 123 df<000FF000007FFC0001F80E0003E01F0007C03F000F803F000F803F000F801E000F80
0C000F8000000F8000000F8000000F800000FFFFFF00FFFFFF000F801F000F801F000F801F000F
801F000F801F000F801F000F801F000F801F000F801F000F801F000F801F000F801F000F801F00
0F801F000F801F000F801F000F801F000F801F007FF0FFE07FF0FFE01B237FA21F>12
D<FFFCFFFCFFFCFFFC0E047F8C13>45 D<387CFEFEFE7C3807077C8610>I<00180000780001F8
00FFF800FFF80001F80001F80001F80001F80001F80001F80001F80001F80001F80001F80001F8
0001F80001F80001F80001F80001F80001F80001F80001F80001F80001F80001F80001F80001F8
0001F8007FFFE07FFFE013207C9F1C>49 D<03FC000FFF003C1FC07007E07C07F0FE03F0FE03F8
FE03F8FE01F87C01F83803F80003F80003F00003F00007E00007C0000F80001F00003E00003800
00700000E01801C0180380180700180E00380FFFF01FFFF03FFFF07FFFF0FFFFF0FFFFF015207D
9F1C>I<00FE0007FFC00F07E01E03F03F03F03F81F83F81F83F81F81F03F81F03F00003F00003
E00007C0001F8001FE0001FF000007C00001F00001F80000FC0000FC3C00FE7E00FEFF00FEFF00
FEFF00FEFF00FC7E01FC7801F81E07F00FFFC001FE0017207E9F1C>I<0000E00001E00003E000
03E00007E0000FE0001FE0001FE00037E00077E000E7E001C7E00187E00307E00707E00E07E00C
07E01807E03807E07007E0E007E0FFFFFEFFFFFE0007E00007E00007E00007E00007E00007E000
07E000FFFE00FFFE17207E9F1C>I<1000201E01E01FFFC01FFF801FFF001FFE001FF8001BC000
18000018000018000018000019FC001FFF001E0FC01807E01803E00003F00003F00003F80003F8
3803F87C03F8FE03F8FE03F8FC03F0FC03F07007E03007C01C1F800FFF0003F80015207D9F1C>
I<001F8000FFE003F07007C0F00F01F81F01F83E01F83E01F87E00F07C00007C0000FC0800FC7F
C0FCFFE0FD80F0FF00F8FE007CFE007CFC007EFC007EFC007EFC007E7C007E7C007E7C007E3C00
7C3E007C1E00F80F00F00783E003FFC000FF0017207E9F1C>I<000070000000007000000000F8
00000000F800000000F800000001FC00000001FC00000003FE00000003FE00000003FE00000006
FF000000067F0000000E7F8000000C3F8000000C3F800000183FC00000181FC00000381FE00000
300FE00000300FE00000600FF000006007F00000E007F80000FFFFF80000FFFFF800018001FC00
018001FC00038001FE00030000FE00030000FE000600007F000600007F00FFE00FFFF8FFE00FFF
F825227EA12A>65 D<0003FE0080001FFF818000FF01E38001F8003F8003E0001F8007C0000F80
0F800007801F800007803F000003803F000003807F000001807E000001807E00000180FE000000
00FE00000000FE00000000FE00000000FE00000000FE00000000FE00000000FE000000007E0000
00007E000001807F000001803F000001803F000003801F800003000F8000030007C000060003F0
000C0001F800380000FF00F000001FFFC0000003FE000021227DA128>67
D<FFFFFF8000FFFFFFF00007F003FC0007F0007E0007F0003F0007F0001F8007F0000FC007F000
07E007F00007E007F00007F007F00003F007F00003F007F00003F007F00003F807F00003F807F0
0003F807F00003F807F00003F807F00003F807F00003F807F00003F807F00003F807F00003F007
F00003F007F00003F007F00007E007F00007E007F0000FC007F0001F8007F0003F0007F0007E00
07F003FC00FFFFFFF000FFFFFF800025227EA12B>I<FFFFFFFCFFFFFFFC07F000FC07F0003C07
F0001C07F0000C07F0000E07F0000E07F0000607F0180607F0180607F0180607F0180007F03800
07F0780007FFF80007FFF80007F0780007F0380007F0180007F0180007F0180307F0180307F000
0307F0000607F0000607F0000607F0000E07F0000E07F0001E07F0003E07F001FCFFFFFFFCFFFF
FFFC20227EA125>I<FFFFFFF8FFFFFFF807F001F807F0007807F0003807F0001807F0001C07F0
001C07F0000C07F0000C07F0180C07F0180C07F0180007F0180007F0380007F0780007FFF80007
FFF80007F0780007F0380007F0180007F0180007F0180007F0180007F0000007F0000007F00000
07F0000007F0000007F0000007F0000007F00000FFFFE000FFFFE0001E227EA123>I<FFFFE0FF
FFE003F80003F80003F80003F80003F80003F80003F80003F80003F80003F80003F80003F80003
F80003F80003F80003F80003F80003F80003F80003F80003F80003F80003F80003F80003F80003
F80003F80003F80003F80003F800FFFFE0FFFFE013227FA115>73 D<FFFFE000FFFFE00007F000
0007F0000007F0000007F0000007F0000007F0000007F0000007F0000007F0000007F0000007F0
000007F0000007F0000007F0000007F0000007F0000007F0000007F0000007F0000007F0001807
F0001807F0001807F0001807F0003807F0003807F0007007F0007007F000F007F001F007F007F0
FFFFFFF0FFFFFFF01D227EA122>76 D<FFF8001FFEFFFC001FFE07FC0000C007FE0000C006FF00
00C0067F8000C0063FC000C0061FE000C0060FE000C0060FF000C00607F800C00603FC00C00601
FE00C00600FE00C00600FF00C006007F80C006003FC0C006001FE0C006000FF0C0060007F0C006
0007F8C0060003FCC0060001FEC0060000FFC00600007FC00600007FC00600003FC00600001FC0
0600000FC006000007C006000003C006000003C0FFF00001C0FFF00000C027227EA12C>78
D<0007FC0000003FFF800000FC07E00003F001F80007E000FC000FC0007E001F80003F001F8000
3F003F00001F803F00001F807F00001FC07E00000FC07E00000FC0FE00000FE0FE00000FE0FE00
000FE0FE00000FE0FE00000FE0FE00000FE0FE00000FE0FE00000FE0FE00000FE07E00000FC07F
00001FC07F00001FC03F00001F803F80003F801F80003F000FC0007E0007E000FC0003F001F800
00FC07E000003FFF80000007FC000023227DA12A>I<FFFFFF00FFFFFFE007F007F007F001FC07
F000FC07F0007E07F0007E07F0007F07F0007F07F0007F07F0007F07F0007F07F0007E07F0007E
07F000FC07F001FC07F007F007FFFFE007FFFF0007F0000007F0000007F0000007F0000007F000
0007F0000007F0000007F0000007F0000007F0000007F0000007F0000007F00000FFFF8000FFFF
800020227EA126>I<FFFFFE0000FFFFFFC00007F007F00007F001F80007F000FC0007F0007E00
07F0007F0007F0007F0007F0007F0007F0007F0007F0007F0007F0007F0007F0007E0007F000FC
0007F001F80007F007F00007FFFFC00007FFFF800007F00FE00007F007F00007F003F80007F001
FC0007F001FC0007F001FC0007F001FC0007F001FC0007F001FC0007F001FC0007F001FC0007F0
01FC0607F000FE0607F000FF0CFFFF803FF8FFFF800FF027227EA12A>82
D<01FC0407FF8C1F03FC3C007C7C003C78001C78001CF8000CF8000CFC000CFC0000FF0000FFE0
007FFF007FFFC03FFFF01FFFF80FFFFC03FFFE003FFE0003FF00007F00003F00003FC0001FC000
1FC0001FE0001EE0001EF0003CFC003CFF00F8C7FFE080FF8018227DA11F>I<FFFF800FFEFFFF
800FFE07F00000C007F80000C003F800018003F800018001FC00030001FC00030001FE00070000
FE00060000FF000600007F000C00007F800C00003F801800003F801800003FC03800001FC03000
001FE03000000FE06000000FF060000007F0C0000007F0C0000007F9C0000003F980000003FD80
000001FF00000001FF00000000FE00000000FE00000000FE000000007C000000007C0000000038
0000000038000027227FA12A>86 D<07FC001FFF803F07C03F03E03F01E03F01F01E01F00001F0
0001F0003FF003FDF01FC1F03F01F07E01F0FC01F0FC01F0FC01F0FC01F07E02F07E0CF81FF87F
07E03F18167E951B>97 D<FF000000FF0000001F0000001F0000001F0000001F0000001F000000
1F0000001F0000001F0000001F0000001F0000001F0000001F0FE0001F3FF8001FF07C001F801E
001F001F001F000F801F000F801F000FC01F000FC01F000FC01F000FC01F000FC01F000FC01F00
0FC01F000FC01F000F801F001F801F801F001FC03E001EE07C001C3FF800180FC0001A237EA21F
>I<00FF8007FFE00F83F01F03F03E03F07E03F07C01E07C0000FC0000FC0000FC0000FC0000FC
0000FC00007C00007E00007E00003E00301F00600FC0E007FF8000FE0014167E9519>I<0001FE
000001FE0000003E0000003E0000003E0000003E0000003E0000003E0000003E0000003E000000
3E0000003E0000003E0001FC3E0007FFBE000F81FE001F007E003E003E007E003E007C003E00FC
003E00FC003E00FC003E00FC003E00FC003E00FC003E00FC003E00FC003E007C003E007C003E00
3E007E001E00FE000F83BE0007FF3FC001FC3FC01A237EA21F>I<00FE0007FF800F87C01E01E0
3E01F07C00F07C00F8FC00F8FC00F8FFFFF8FFFFF8FC0000FC0000FC00007C00007C00007E0000
3E00181F00300FC07003FFC000FF0015167E951A>I<003F8000FFC001E3E003C7E007C7E00F87
E00F83C00F80000F80000F80000F80000F80000F8000FFFC00FFFC000F80000F80000F80000F80
000F80000F80000F80000F80000F80000F80000F80000F80000F80000F80000F80000F80000F80
000F80007FF8007FF80013237FA211>I<03FC1E0FFF7F1F0F8F3E07CF3C03C07C03E07C03E07C
03E07C03E07C03E03C03C03E07C01F0F801FFF0013FC003000003000003800003FFF801FFFF00F
FFF81FFFFC3800FC70003EF0001EF0001EF0001EF0001E78003C7C007C3F01F80FFFE001FF0018
217E951C>I<FF000000FF0000001F0000001F0000001F0000001F0000001F0000001F0000001F
0000001F0000001F0000001F0000001F0000001F07E0001F1FF8001F307C001F403C001F803E00
1F803E001F003E001F003E001F003E001F003E001F003E001F003E001F003E001F003E001F003E
001F003E001F003E001F003E001F003E001F003E00FFE1FFC0FFE1FFC01A237EA21F>I<1C003F
007F007F007F003F001C000000000000000000000000000000FF00FF001F001F001F001F001F00
1F001F001F001F001F001F001F001F001F001F001F001F001F00FFE0FFE00B247EA310>I<FF00
0000FF0000001F0000001F0000001F0000001F0000001F0000001F0000001F0000001F0000001F
0000001F0000001F0000001F00FF801F00FF801F0038001F0060001F01C0001F0380001F070000
1F0E00001F1C00001F7E00001FFF00001FCF00001F0F80001F07C0001F03E0001F01E0001F01F0
001F00F8001F007C001F003C00FFE0FFC0FFE0FFC01A237EA21E>107 D<FF00FF001F001F001F
001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F00
1F001F001F001F001F001F001F001F001F00FFE0FFE00B237EA210>I<FF07F007F000FF1FFC1F
FC001F303E303E001F403E403E001F801F801F001F801F801F001F001F001F001F001F001F001F
001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F00
1F001F001F001F001F001F001F001F001F001F001F001F001F001F001F001F00FFE0FFE0FFE0FF
E0FFE0FFE02B167E952F>I<FF07E000FF1FF8001F307C001F403C001F803E001F803E001F003E
001F003E001F003E001F003E001F003E001F003E001F003E001F003E001F003E001F003E001F00
3E001F003E001F003E001F003E00FFE1FFC0FFE1FFC01A167E951F>I<00FE0007FFC00F83E01E
00F03E00F87C007C7C007C7C007CFC007EFC007EFC007EFC007EFC007EFC007EFC007E7C007C7C
007C3E00F81F01F00F83E007FFC000FE0017167E951C>I<FF0FE000FF3FF8001FF07C001F803E
001F001F001F001F801F001F801F000FC01F000FC01F000FC01F000FC01F000FC01F000FC01F00
0FC01F000FC01F001F801F001F801F803F001FC03E001FE0FC001F3FF8001F0FC0001F0000001F
0000001F0000001F0000001F0000001F0000001F0000001F000000FFE00000FFE000001A207E95
1F>I<FE1F00FE3FC01E67E01EC7E01E87E01E87E01F83C01F00001F00001F00001F00001F0000
1F00001F00001F00001F00001F00001F00001F00001F0000FFF000FFF00013167E9517>114
D<0FF3003FFF00781F00600700E00300E00300F00300FC00007FE0007FF8003FFE000FFF0001FF
00000F80C00780C00380E00380E00380F00700FC0E00EFFC00C7F00011167E9516>I<01800001
80000180000180000380000380000780000780000F80003F8000FFFF00FFFF000F80000F80000F
80000F80000F80000F80000F80000F80000F80000F80000F80000F81800F81800F81800F81800F
81800F830007C30003FE0000F80011207F9F16>I<FF01FE00FF01FE001F003E001F003E001F00
3E001F003E001F003E001F003E001F003E001F003E001F003E001F003E001F003E001F003E001F
003E001F003E001F003E001F007E001F00FE000F81BE0007FF3FC001FC3FC01A167E951F>I<FF
E01FE0FFE01FE00F8006000F8006000FC00E0007C00C0007E01C0003E0180003E0180001F03000
01F0300000F8600000F86000007CC000007CC000007FC000003F8000003F8000001F0000001F00
00000E0000000E00001B167F951E>I<FFE7FF07F8FFE7FF07F81F007800C00F807801800F807C
01800F807C018007C07E030007C0DE030007E0DE070003E0DF060003E18F060001F18F0C0001F3
8F8C0001FB079C0000FB07D80000FE03D800007E03F000007E03F000007C01F000003C01E00000
3800E000001800C00025167F9528>I<FFE07FC0FFE07FC00F801C0007C0380003E0700003F060
0001F8C00000F98000007F8000003F0000001F0000001F8000003FC0000037C0000063E00000C1
F00001C0F8000380FC0007007E000E003E00FF80FFE0FF80FFE01B167F951E>I<FFE01FE0FFE0
1FE00F8006000F8006000FC00E0007C00C0007E01C0003E0180003E0180001F0300001F0300000
F8600000F86000007CC000007CC000007FC000003F8000003F8000001F0000001F0000000E0000
000E0000000C0000000C00000018000078180000FC380000FC300000FC60000069C000007F8000
001F0000001B207F951E>I<7FFFF07FFFF07C03E07007C0600FC0E01F80C01F00C03E00C07E00
00FC0000F80001F00003F03007E03007C0300F80701F80703F00603E00E07C03E0FFFFE0FFFFE0
14167E9519>I E end
%%EndProlog
%%BeginSetup
%%Feature: *Resolution 300
TeXDict begin 
%%EndSetup
%%Page: 1 1
bop 138 45 a Fr(Visa)19 b(Proto)r(cols)f(for)g(Con)n(trolling)h(In)n
(ter-Organizational)e(Datagram)i(Flo)n(w)1792 27 y Fq(1)520
220 y Fp(Deb)q(orah)d(Estrin,)e(Je\013rey)h(Mogul,)f(Gene)h(Tsudik)1410
203 y Fq(2)821 483 y Fp(Deb)q(orah)g(Estrin)848 540 y(Gene)g(Tsudik)669
653 y(Computer)g(Science)h(Departmen)o(t)645 709 y(Univ)o(ersit)o(y)d(of)i
(Southern)h(California)627 765 y(Los)f(Angeles,)g(California)e(90089-0782)753
822 y(estrin@usc-cse.usc.edu)748 878 y(tsudik@usc-cse.usc.edu)839
991 y(Je\013rey)i(Mogul)662 1104 y(Digital)e(Equipmen)o(t)i(Corp)q(oration)
679 1161 y(W)l(estern)g(Researc)o(h)h(Lab)q(oratory)746 1217
y(mogul@decwrl.dec.com)884 1580 y Fo(Abstract)176 1683 y Fn(The)g(increasing)
h(use)g(of)e(in)o(ternet)o(w)o(orking)h(proto)q(cols)g(to)g(connect)i
(administrativ)o(ely)13 b(heterogeneous)114 1733 y(net)o(w)o(orks)18
b(has)g(raised)g(the)h(question)f(of)f(ho)o(w)h(an)g(organization)e(can)i
(con)o(trol)g(the)g(\015o)o(w)g(of)f(information)114 1782 y(across)h(its)f
(net)o(w)o(ork)h(b)q(oundaries.)29 b(One)18 b(metho)q(d)f(for)g(doing)f(so)i
(is)f(the)h(use)g(of)f Fm(visas)p Fn(,)h(a)f(cryptographic)114
1832 y(tec)o(hnique)12 b(for)f(authen)o(ticating)h(and)f(authorizing)g(a)g
(\015o)o(w)h(of)f(datagrams.)k(This)d(pap)q(er)g(presen)o(ts)i(and)d(ev)n
(al-)114 1882 y(uates)k(t)o(w)o(o)g Fm(visa)g Fn(proto)q(cols)g(-)g(one)g
(that)g(requires)h(distributed)g(state)g(information)c(in)i(gatew)o(a)o(ys)h
(and)g(one)114 1932 y(that)h(uses)i(additional)d(encryption)i(op)q(erations)g
(instead)g(of)e(distributed)j(state.)26 b(Applications)16 b(for)h(suc)o(h)114
1982 y Fm(visa)h Fn(proto)q(cols)i(include)e(access)j(con)o(trol,)f(accoun)o
(ting)e(and)h(billing)e(for)h(pac)o(k)o(et)i(transit,)f(and)g(net)o(w)o(ork)
114 2031 y(resource)d(managem)o(en)o(t.)114 2131 y Fo(Key)j(W)l(ords:)24
b Fn(Computer)16 b(net)o(w)o(orks,)i(net)o(w)o(ork)f(in)o(terconnection,)h
(net)o(w)o(ork)f(securit)o(y)m(,)g(access)i(con)o(trol,)114
2181 y(authen)o(tication,)13 b(cryptographic)h(proto)q(cols.)p
0 2257 780 2 v 52 2284 a Fl(1)69 2300 y Fk(This)h(researc)o(h)g(w)o(as)g
(funded)h(in)f(part)g(b)o(y)g(the)g(National)g(Science)g(F)m(oundation,)i
(Presiden)o(tial)e(Y)m(oung)g(In)o(v)o(estigator)g(Aw)o(ard,)0
2345 y(with)e(matc)o(hing)h(funds)h(from)e(GTE)h(Inc.)19 b(and)14
b(NCR)g(Inc.,)f(and)h(b)o(y)g(the)g(Univ)o(ersit)o(y)g(of)f(Southern)i
(California)e(F)m(acult)o(y)h(Researc)o(h)0 2391 y(Initiation)f(F)m(und.)k(P)
o(ortions)d(w)o(ere)e(funded)i(b)o(y)f(the)h(Digital)e(Equipmen)o(t)i(Corp)q
(oration)g(W)m(estern)f(Researc)o(h)h(Lab)q(oratory)m(.)52
2421 y Fl(2)69 2437 y Fk(Names)f(are)g(listed)g(in)g(alphab)q(etical)g
(order.)964 2828 y Fp(1)p eop
%%Page: 2 2
bop 0 45 a Fj(Con)n(ten)n(ts)964 2828 y Fp(2)p eop
%%Page: 3 3
bop 0 45 a Fj(1)69 b(In)n(tro)r(duction)0 186 y Fp(The)17 b(lo)q(cal-area)e
(and)i(long-haul)e(net)o(w)o(orks)h(of)g(man)o(y)g(distinct)g(organizations)e
(can)j(b)q(e)g(joined)f(together)g(in)o(to)0 242 y(an)g Fi(internetwork)g
Fp(through)g(whic)o(h)g(datagrams)f(\015o)o(w)g(without)h(regard)f(to)h
(organizational)e(b)q(oundaries.)23 b(The)0 299 y(transparency)e(of)f(an)h
(in)o(ternet)o(w)o(ork)e(is)h(b)q(oth)h(a)g(blessing)f(and)h(a)g(curse:)32
b(a)20 b(blessing)g(b)q(ecause)i(it)e(pro)o(vides)0 355 y(univ)o(ersal)11
b(connectivit)o(y)g(without)f(requiring)h(application-sp)q(eci\014c)h(gatew)o
(a)o(ys,)e(and)i(a)f(curse)h(b)q(ecause)h(it)e(mak)o(es)0 412
y(it)j(m)o(uc)o(h)i(harder)f(to)f(con)o(trol)g(the)i(\015o)o(w)e(of)h
(information)e(b)q(et)o(w)o(een)j(organizations.)71 507 y(Early)h(in)o
(ternet)o(w)o(orks)f(ignored)h(the)i(issue)e(of)h(con)o(trol,)f(either)h(b)q
(ecause)h(they)f(connected)h(organizations)0 564 y(within)12
b(a)h(larger)g(administrativ)o(e)d(unit)j(\(suc)o(h)h(as)f(a)g(single)f(corp)
q(oration,)g(univ)o(ersit)o(y)l(,)g(or)h(go)o(v)o(ernmen)o(tal)f(b)q(o)q
(dy\))0 620 y(or)19 b(b)q(ecause)h(they)g(connected)g(researc)o(h)f
(institutions)f(with)h(little)f(need)i(to)f(limit)e(information)h(\015o)o(w.)
32 b(Cur-)0 676 y(ren)o(t)20 b(in)o(ternet)o(w)o(orks)f(connect)j
(organizations)c(that)i(ma)o(y)g(ha)o(v)o(e)h(comp)q(eting)f(in)o(terests.)36
b(Th)o(us,)22 b(w)o(e)e(can)h(no)0 733 y(longer)16 b(ignore)g(the)h(need)h
(for)e(con)o(trolling)e(in)o(ter-organizational)g(information)h(\015o)o(w.)24
b(Similarly)l(,)15 b(in)i(a)f(m)o(ulti-)0 789 y(organization)9
b(in)o(ternet)o(w)o(ork,)g(costs)h(m)o(ust)h(b)q(e)g(billed)f(to)g
(individual)g(organizations)f(or)h(departmen)o(ts,)h(resulting)0
846 y(in)k(a)g(gro)o(wing)e(need)k(for)d(secure)i(proto)q(cols)e(to)h(accoun)
o(t)f(for)h(datagram)f(tra\016c.)71 941 y(One)21 b(approac)o(h)g(is)f(to)g
(in)o(tro)q(duce)h(con)o(trols)f(at)g(a)g(n)o(um)o(b)q(er)i(of)e(lev)o(els)g
(in)h(the)g(proto)q(col)f(hierarc)o(h)o(y)l(.)36 b(W)l(e)0
998 y(w)o(ould)15 b(lik)o(e)f(to)g(preserv)o(e)i(the)f(useful)g(prop)q
(erties)g(of)g(datagram-lev)o(el)e(transparency)i(b)o(y)g(con)o(trolling)e
(the)i(\015o)o(w)0 1054 y(of)f(individual)g(datagrams.)k(W)l(e)d(assume)g
(that)f(higher-lev)o(el)g(con)o(trols)f(will)h(b)q(e)h(implemen)o(ted)g(as)f
(appropriate)0 1111 y(to)h(the)g(particular)f(applications)f(and)j
(organizations)d(in)o(v)o(olv)o(ed.)71 1206 y(T)l(o)h(pro)o(vide)h
(datagram-lev)o(el)e(con)o(trol,)g(Estrin)h(and)i(Tsudik)e(ha)o(v)o(e)h(prop)
q(osed)g(the)g Fi(Visa)g Fp(sc)o(heme[)p Fh(?)p Fp(].)k(Con-)0
1263 y(ceptually)l(,)d(a)g(secret)g(k)o(ey)h(is)e(used)i(to)f(compute)h(an)f
(unforgeable)g(mark)g(placed)g(on)h(a)f(datagram)e(to)i(assure)g(a)0
1319 y(gatew)o(a)o(y)11 b(that)i(in)o(ter-organizational)d(transmission)h(of)
i(that)f(datagram)g(is)g(prop)q(erly)h(authorized.)19 b(This)13
b(mark)0 1376 y(is)k(called)f(a)h Fi(visa)p Fp(,)g(b)o(y)g(analogy)e(with)i
(the)g(stamp)f(made)h(on)g(a)g(passp)q(ort)f(that)h(allo)o(ws)e(the)i(b)q
(earer)g(to)g(cross)f(a)0 1432 y(b)q(order.)k(W)l(e)13 b(bind)h(eac)o(h)g
(visa)f(to)g(a)g(single)g(datagram)f(in)i(order)f(to)g(guaran)o(tee)g(the)h
(authen)o(ticit)o(y)e(of)h(datagram)0 1489 y(con)o(ten)o(ts.)21
b(Visas)15 b(w)o(ere)h(\014rst)g(suggested)f(b)o(y)h(Da)o(vid)f(Reed,)i(and)f
(do)q(cumen)o(ted)g(b)o(y)g(J.)g(Mracek[)p Fh(?)p Fp(].)21
b(A)15 b(detailed)0 1545 y(analysis)21 b(of)g(the)h(issues)g(asso)q(ciated)f
(with)g(in)o(ter-organizational)e(net)o(w)o(orks,)j(as)f(w)o(ell)g(as)h(the)g
(motiv)m(ations)0 1602 y(b)q(ehind)16 b(the)g(visa)e(sc)o(heme,)h(can)g(b)q
(e)h(found)g(in)f([)p Fh(?)p Fp(].)71 1697 y(In)g(general,)g(a)g(host)f(on)h
(a)g(visa-con)o(trolled)f(net)o(w)o(ork)g(that)g(w)o(an)o(ts)g(to)h(comm)o
(unicate)f(across)h(its)f(organiza-)0 1754 y(tional)h(b)q(oundary)i
(initially)e(engages)h(in)h(a)f(high-lev)o(el)g(authorization)f(and)i(authen)
o(tication)e(pro)q(cedure)j(with)0 1810 y(the)f(Access)g(Con)o(trol)e(Serv)o
(ers)i(\(A)o(CSs\))e(on)i(b)q(oth)g(source)g(and)g(destination)e(net)o(w)o
(orks)h(\(see)g(\014gure)h Fh(??)p Fp(\).)24 b(The)0 1867 y(need)19
b(for)e(\(and)h(particulars)f(of)t(\))g(A)o(CS)h(authorization)e(is)i
(determined)g(individually)f(b)o(y)h(the)h(o)o(wners)e(of)h(the)0
1923 y(end-p)q(oin)o(t)d(net)o(w)o(orks.)k(When)c(a)g(source-destination)f
(connection)h(has)g(b)q(een)h(appro)o(v)o(ed)f(b)o(y)g(an)g(A)o(CS)g(on)g
(eac)o(h)0 1979 y(net)o(w)o(ork,)20 b(the)h(A)o(CSs)f(allo)q(cate)g
Fi(visas)f Fp(to)h(the)h(requesting)f(host.)35 b(The)21 b(host)f(uses)h(the)g
(visas)e(to)h(stamp)g(all)0 2036 y(datagrams)14 b(b)q(elonging)h(to)g(that)g
(connection.)21 b(The)15 b(b)q(order)h(gatew)o(a)o(ys)e(\(\\visa-gatew)o(a)o
(ys"\))e(of)j(the)h(end-p)q(oin)o(t)0 2092 y(organizations)e(c)o(hec)o(k)j
(all)e(datagrams)g(for)g(appropriate)h(stamping,)f(and)h(pass)g(authorized)g
(datagrams)f(un)o(til)0 2149 y(a)g(visa)f(expires)h(or)g(is)f(rev)o(ok)o(ed.)
20 b(Eac)o(h)15 b(gatew)o(a)o(y)e(c)o(hec)o(ks)i(the)g(authorization)f(of)g
(a)h(datagram)f(to)g(en)o(ter)h(or)g(exit)0 2205 y(the)j(attac)o(hed)g(net)o
(w)o(ork,)f(not)g(whether)i(the)f(datagram)e(is)i(authorized)g(to)f(tra)o(v)o
(el)f(all)h(the)i(w)o(a)o(y)e(from)g(source)0 2262 y(to)e(destination.)21
b(Visa-gatew)o(a)o(ys)13 b(ma)o(y)i(also)g(use)h(visa)f(information)f(to)h
(ensure)h(that)f(the)h(prop)q(er)g(parties)f(are)0 2318 y(billed)g(for)f(the)
i(cost)e(of)h(carrying)f(the)i(datagrams.)71 2414 y(In)23 b(this)g(pap)q(er)g
(w)o(e)g(presen)o(t)g(t)o(w)o(o)f(v)m(ariations)f(of)i(the)g(proto)q(col)f
(originally)f(prop)q(osed)j(b)o(y)f(Estrin)f(and)0 2470 y(Tsudik[)p
Fh(?)p Fp(].)32 b(One)20 b(is)g(an)f(impro)o(v)o(ed)g(v)o(ersion)g(of)g(the)h
(original)e(\(\\stateful"\))f(proto)q(col,)i(in)h(whic)o(h)f(the)h(A)o(CSs)0
2527 y(distribute)c(visas)g(to)g(the)g(gatew)o(a)o(ys)f(in)o(v)o(olv)o(ed.)23
b(The)17 b(other)f(\(\\stateless"\))f(v)m(arian)o(t)g(a)o(v)o(oids)h(the)g
(necessit)o(y)h(for)0 2583 y(distributed)h(state,)g(but)h(requires)g
(additional)e(encryption)h(steps.)30 b(W)l(e)19 b(then)g(analyze)f(the)h(dra)
o(wbac)o(ks)f(and)0 2640 y(adv)m(an)o(tages)e(of)h(these)g(t)o(w)o(o)f(proto)
q(cols)g(based)h(on)g(con)o(v)o(en)o(tional)e(single-k)o(ey)h(\(\\priv)m
(ate-k)o(ey"\))g(cryptograph)o(y)l(.)0 2696 y(\(A)f(public-k)o(ey)g(v)m
(ariation)f(of)h(the)g(stateless)f(proto)q(col)g(is)h(discussed)h(in)f([)p
Fh(?)p Fp(].\))964 2828 y(3)p eop
%%Page: 4 4
bop 275 2136 a Fp(Figure)15 b(1:)k(Tw)o(o)c(in)o(terconnected)g
(organizations)e(running)i(the)h(visa)e(proto)q(col.)964 2828
y(4)p eop
%%Page: 5 5
bop 0 45 a Fr(1.1)56 b(P)n(olicies)0 170 y Fp(Visas)20 b(are)g(a)h
Fi(me)n(chanism)e Fp(for)h(authen)o(ticating)g(the)g(source,)i(destination,)f
(and)f(con)o(ten)o(ts)g(of)h(a)f(datagram.)0 227 y(Authen)o(tication)13
b(in)g(itself)f(is)i(not)f(an)g(end)i(but)e(a)h(means)f(for)g(implemen)o
(ting)g(a)g(p)q(olicy)l(,)g(suc)o(h)h(as)f(access)h(con)o(trol)0
283 y(or)i(accoun)o(ting.)22 b(An)16 b(access)g(con)o(trol)f(p)q(olicy)l(,)h
(applied)g(to)f(datagrams,)g(requires)h(a)f(gatew)o(a)o(y)g(to)g(determine)h
(if)0 339 y(the)f(authen)o(ticated)f(parties)h(are)f(indeed)i(authorized)f
(to)f(comm)o(unicate.)19 b(\(Visa)14 b(proto)q(cols)g(describ)q(ed)i(in)f
(this)0 396 y(pap)q(er)j(allo)o(w)d(only)i(authorized)f(pairs)h(of)f(hosts)h
(to)f(b)q(e)i(authen)o(ticated.\))25 b(An)17 b(accoun)o(ting)g(p)q(olicy)f
(requires)h(a)0 452 y(gatew)o(a)o(y)12 b(to)h(c)o(harge)g(the)g(resources)g
(used)h(to)f(an)h(authen)o(ticated)e(host;)i(in)f(this)g(con)o(text)g(a)g
(visa)f(is)h(a)g(certi\014cate)0 509 y(that)j(the)h(host)f(has)h(promised)f
(to)g(pa)o(y)h(its)f(bills.)23 b(A)17 b(resource)g(managemen)o(t)f(p)q(olicy)
h(requires)f(a)h(gatew)o(a)o(y)e(to)0 565 y(ensure)f(that)e(the)h(authen)o
(ticated)g(host)g(has)g(not)g(used)g(up)h(its)e(quota)h(of)f(resources)i
(\(for)e(example,)h(if)f(datagram)0 622 y(c)o(harges)j(m)o(ust)f(b)q(e)i
(prepaid\).)71 717 y(In)i(the)h(visa)e(proto)q(cols)g(w)o(e)h(describ)q(e,)i
(gatew)o(a)o(ys)c(do)i(not)g(b)q(ear)h(sole)f(resp)q(onsibilit)o(y)e(for)i
(making)f(p)q(olicy)0 774 y(decisions.)k(By)16 b(issuing)f(a)g(visa,)g(an)h
(A)o(CS)f(has)h(precomputed)g(a)g(decision)f(suc)o(h)h(as)f(\\these)h(hosts)f
(are)h(allo)o(w)o(ed)0 830 y(to)f(comm)o(unicate,")g(or)h(\\this)f(host)h
(can)g(b)q(e)h(trusted)e(to)h(pa)o(y)g(its)f(bills.")21 b(The)16
b(task)g(of)f(a)h(gatew)o(a)o(y)e(is)i(reduced)0 887 y(to)k(ensuring)h(that)f
(the)g(visa)g(is)g(v)m(alid)h(and)g(is)f(b)q(eing)h(used)g(correctly;)h(the)f
(exp)q(ensiv)o(e)g(part)f(of)h(the)f(p)q(olicy)0 943 y(implemen)o(tation)15
b(is)h(done)g(once)h(p)q(er)g(connection,)f(b)o(y)h(the)f(A)o(CS,)g(rather)g
(than)g(once)h(p)q(er)g(datagram,)e(b)o(y)h(the)0 1000 y(gatew)o(a)o(y)l(.)71
1095 y(This)11 b(pap)q(er)i(emphasizes)g(problems)f(of)f(access)i(con)o
(trol;)e(visa)h(proto)q(cols)f(describ)q(ed)i(here)g(are)f(designed)h(for)0
1152 y(that)i(purp)q(ose.)23 b(Accoun)o(ting)16 b(and)g(resource)g(managemen)
o(t)f(app)q(ear)h(to)g(b)q(e)g(simpler)g(problems;)f(for)g(example,)0
1208 y(one)f(ma)o(y)f(tolerate)f(mo)q(derate)h(\\leak)m(age",)g(resulting)f
(in)i(sligh)o(tly)d(incorrect)i(bills,)g(if)g(the)g(net)h(result)f(is)g(a)g
(lo)o(w)o(er)0 1265 y(o)o(v)o(erhead)k(cost)g(for)g(doing)g(the)h(billing.)26
b(Also,)17 b(it)g(is)g(necessary)h(to)f(authen)o(ticate)g(only)g(one)h(part)o
(y)e(\(the)i(one)0 1321 y(who)c(is)g(pa)o(ying\))f(if)g(the)i(only)e
(application)g(is)h(billing.)k(Therefore,)c(in)g(an)g(en)o(vironmen)o(t)g
(where)g(visas)f(are)h(used)0 1377 y(for)g(accoun)o(ting)f(and)i(not)f(for)f
(access)i(con)o(trol,)e(somewhat)g(di\013eren)o(t)h(proto)q(cols)f(ma)o(y)g
(b)q(e)i(appropriate;)f(this)f(is)0 1434 y(the)i(sub)s(ject)g(of)g(w)o(ork)f
(in)h(progress[)p Fh(?)p Fp(].)0 1595 y Fr(1.2)56 b(Net)n(w)n(ork)18
b(en)n(vironmen)n(t)0 1720 y Fp(W)l(e)13 b(will)g(assume)g(that)g(the)g(in)o
(ternet)o(w)o(ork)f(closely)g(follo)o(ws)g(the)h(mo)q(del)h(of)f(the)g(D)o
(ARP)l(A)h(In)o(ternet[)p Fh(?)p Fp(],)e(whic)o(h)h(is)0 1776
y(substan)o(tially)d(similar)g(to)i(the)g(Op)q(en)h(Systems)f(In)o
(terconnection)g(\(OSI\))g(mo)q(del[)p Fh(?)p Fp(,)f Fh(?)p
Fp(].)18 b(The)12 b(essen)o(tial)f(features)0 1833 y(of)k(the)g(en)o
(vironmen)o(t)g(are:)68 1966 y Fg(\017)23 b Fp(Hosts)14 b(are)h(autonomous)f
(and)i(cannot)f(necessarily)f(b)q(e)i(trusted.)68 2059 y Fg(\017)23
b Fp(Organizational)16 b(net)o(w)o(orks)h(are)h(connected)h(b)o(y)g(gatew)o
(a)o(ys;)e(b)q(et)o(w)o(een)i(an)o(y)f(pair)g(of)g(hosts)g(in)g(di\013eren)o
(t)114 2116 y(organizations)f(there)j(are)f(at)h(least)e(t)o(w)o(o)h(gatew)o
(a)o(ys,)f(one)i(b)q(elonging)f(to)h(eac)o(h)f(of)h(the)f(organizations.)114
2172 y(Conceptually)l(,)14 b(the)h(connection)g(b)q(et)o(w)o(een)g(t)o(w)o(o)
f(organizations)e(is)j(a)f(pair)h(of)f(half-gatew)o(a)o(ys)f(connected)114
2229 y(via)h(a)h(trusted)g(link.)k(Eac)o(h)c(half-gatew)o(a)o(y)e(can)j(b)q
(e)g(trusted)f(b)o(y)g(its)f(o)o(wn)h(organization)e(but)i(not)g(b)o(y)g(an)o
(y)114 2285 y(other)f(organization.)68 2379 y Fg(\017)23 b
Fp(All)10 b(information)g(\015o)o(ws)h(via)f(datagrams.)17
b(A)12 b(datagram)e(consists)g(of)h(a)g Fi(he)n(ader)h Fp(that)f(includes)g
(addressing)114 2435 y(information)i(and)i(a)g(data)g(segmen)o(t)g(that)f(is)
h(not)g(in)o(telligible)d(to)j(gatew)o(a)o(ys.)68 2529 y Fg(\017)23
b Fp(A)11 b(datagram)f(ma)o(y)h(\015o)o(w)g(through)h(sev)o(eral)e(\\un)o
(trusted")h(organizations)f(on)h(its)g(w)o(a)o(y)g(to)g(the)g(destination.)68
2623 y Fg(\017)23 b Fp(Host)12 b(addresses,)g(b)q(oth)h(source)g(and)f
(destination,)g(can)h(b)q(e)g(forged.)19 b(It)12 b(is)g(not)g(p)q(ossible)h
(\(using)f(hardw)o(are)114 2680 y(metho)q(ds\))g(to)g(determine)h(reliably)e
(whic)o(h)i(host)f(actually)f(sen)o(t)h(a)h(datagram)e(or)h(to)g(prev)o(en)o
(t)g(a)g(datagram)964 2828 y(5)p eop
%%Page: 6 6
bop 114 45 a Fp(from)18 b(b)q(eing)i(seen)g(b)o(y)f(unauthorized)h(hosts;)h
(in)e(other)g(w)o(ords,)h(man)o(y)f(Lo)q(cal-Area)g(Net)o(w)o(ork)f(\(LAN\))
114 102 y(tec)o(hnologies)c(can)h(b)q(e)h(wire-tapp)q(ed.)68
195 y Fg(\017)23 b Fp(Duplicate)12 b(datagrams)f(and)i(o)q(ccasional)f(lost)g
(datagrams)f(are)i(natural)f(consequences)i(of)e(using)h(a)f(data-)114
252 y(gram)h(net)o(w)o(ork.)18 b(Therefore,)c(if)f(a)h(malicious)f(host)g
(duplicates)h(datagrams)e(from)i(time)f(to)g(time,)h(w)o(e)f(are)114
308 y(willing)g(to)i(accept)g(the)g(co)o(v)o(ert)g(c)o(hannel)g(created)g(b)o
(y)g(this)g(metho)q(d.)0 469 y Fr(1.3)56 b(Design)18 b(goals)0
594 y Fp(The)f(purp)q(ose)g(of)f(the)g(visa)g(proto)q(cols)f(is)h(to)g(allo)o
(w)f(an)h(organization)e(to)i(gran)o(t)g(certain)f(privileges)h(to)g(select,)
0 651 y(trusted)g(hosts)g(and)g(to)g(pro)o(vide)g(a)g(means)g(for)g(prev)o
(en)o(ting)g(the)g(abuse)h(of)f(suc)o(h)g(privileges.)23 b(This)16
b(is)f(but)i(one)0 707 y(comp)q(onen)o(t)f(in)h(the)f(pro)o(vision)f(of)h
(complete)g(securit)o(y)l(.)23 b(The)17 b(success)g(of)f(a)g(visa-based)g
(system)g(assumes)g(the)0 763 y(abilit)o(y)d(to)i(trust)f(certain)h(hosts)g
(not)g(to)f(misuse)h(visas.)71 859 y(Our)i(primary)e(goal)h(is)g(to)g(allo)o
(w)e(an)j(organization)e(to)h(con)o(trol)f(the)i(transmission)e(of)h
(datagrams)f(to)h(and)0 916 y(from)g(hosts)g(in)h(other)g(organizations.)22
b(If)17 b(the)g(sp)q(eci\014c)h(hosts)e(in)o(v)o(olv)o(ed)g(can)h(b)q(e)h
(trusted)e(then)h(w)o(e)g(can)g(meet)0 972 y(a)22 b(stronger)f(goal:)33
b(w)o(e)22 b(can)h(con)o(trol)e(the)h(transmission)e(of)i(datagrams)f(to)h
(and)g(from)g Fi(a)h(sp)n(e)n(ci\014c)d Fp(host)i(in)0 1028
y(another)16 b(organization.)22 b(In)17 b(a)f(datagram)f(net)o(w)o(ork,)g(as)
h(opp)q(osed)h(to)f(a)g(circuit-switc)o(hed)g(net)o(w)o(ork,)f(the)h(only)0
1085 y(information)h(a)o(v)m(ailable)h(ab)q(out)h(a)f(datagram)g(m)o(ust)g(b)
q(e)i(attac)o(hed)f(to)f(the)h(datagram)f(rather)g(than)h(inferred)0
1141 y(from)c(the)g(route)g(the)h(datagram)d(follo)o(ws.)19
b(Therefore,)c(w)o(e)g(can)g(state)g(these)h(goals)e(more)h(directly)f(as)h
(follo)o(ws.)0 1198 y(An)e(organization)e(can)i(guaran)o(tee)f(that:)18
b(a)12 b(datagram)f(can)i(lea)o(v)o(e)f(the)h(source)g(organization)d
Ff(O)1665 1205 y Fe(sr)q(c)1728 1198 y Fp(only)j(if)f Ff(O)1900
1205 y Fe(sr)q(c)0 1254 y Fp(has)h(authorized)g(the)h(sender)f(to)g(send)h
(datagrams)e(to)g(the)i(apparen)o(t)f(destination)f(host,)h(and)g(a)g
(datagram)f(can)0 1311 y(en)o(ter)17 b(the)g(destination)g(organization)e
Ff(O)732 1318 y Fe(dst)798 1311 y Fp(only)i(if)g Ff(O)979 1318
y Fe(dst)1045 1311 y Fp(has)g(authorized)g(the)g(sender)h(to)f(send)h
(datagrams)0 1367 y(to)c(the)h(apparen)o(t)g(destination)e(host.)20
b(Visa)14 b(proto)q(cols)g(also)g(allo)o(w)f(eac)o(h)i(con)o(trolling)d
(organization)h(to)i(rev)o(ok)o(e)0 1424 y(the)g(privileges)f(it)h(has)g
(gran)o(ted.)71 1519 y(Another)d(goal)f(is)h(to)f(add)i(no)f(cost)g(to)g(in)o
(tra-organizatio)o(nal)d(datagram)i(tra\016c,)h(nor)g(to)f(imp)q(ose)i
(additional)0 1576 y(securit)o(y)j(measures)h(up)q(on)g(hosts)f(that)h(do)f
(not)h(participate)e(in)i(in)o(ter-organizational)c(tra\016c.)24
b(Similarly)l(,)15 b(w)o(e)0 1632 y(wish)20 b(to)f(limit)f(the)i(o)o(v)o
(erhead)g(imp)q(osed)g(up)q(on)h(organizations)d(who)h(are)h(not)g(concerned)
h(with)e(con)o(trolling)0 1689 y(external)c(access.)71 1784
y(Finally)l(,)k(w)o(e)g(w)o(an)o(t)f(to)h(minimize)g(the)h(costs)f(imp)q
(osed)g(b)o(y)h(the)f(visa)g(proto)q(cols,)g(including:)29
b(additional)0 1841 y(p)q(er-pac)o(k)o(et)17 b(pro)q(cessing)g(time)f(in)h(b)
q(oth)g(hosts)f(and)h(gatew)o(a)o(ys,)e(additional)g(storage)h(requiremen)o
(ts)g(for)g(hosts)0 1897 y(and)c(gatew)o(a)o(ys,)e(extra)h(datagrams)g(sen)o
(t)g(during)h(connection)g(setup,)g(incremen)o(ts)f(in)h(the)g(length)f(of)h
(datagrams)0 1954 y(\(increasing)17 b(length)g(increases)h(latency)f(and)h
(decreases)h(throughput\),)e(costs)g(of)h(reco)o(v)o(ering)f(from)g(gatew)o
(a)o(y)0 2010 y(crashes,)e(and)g(complexit)o(y)f(of)h(the)g(implemen)o
(tations.)71 2106 y(The)h(securit)o(y)f(of)h(visa)f(proto)q(cols)g(dep)q
(ends)i(up)q(on)g(the)f(secure)g(op)q(eration)f(of)h(participating)e(A)o
(CSs,)i(gate-)0 2162 y(w)o(a)o(ys,)i(and)h(hosts,)g(as)g(w)o(ell)f(as)g(up)q
(on)i(secure)f(distribution)f(of)g(visas)g(from)h(A)o(CSs)f(to)h(gatew)o(a)o
(ys)e(and)i(hosts.)0 2218 y(Discussion)13 b(of)h(mec)o(hanisms)f(to)h
(implemen)o(t)f(suc)o(h)i(securit)o(y)e(is)h(b)q(ey)o(ond)g(the)h(scop)q(e)f
(of)g(this)f(pap)q(er)i(and)f(can)g(b)q(e)0 2275 y(found)i(elsewhere[)p
Fh(?)p Fp(].)0 2436 y Fr(1.4)56 b(Structure)18 b(of)g(this)h(pap)r(er)0
2561 y Fp(The)12 b(remainder)f(of)g(this)f(pap)q(er)i(is)f(organized)g(as)g
(follo)o(ws.)17 b(Section)11 b(2)g(describ)q(es)h(the)f(notation)f(and)i(the)
f(general)0 2617 y(features)h(of)f(the)i(visa)e(proto)q(cols.)18
b(Section)12 b(3)g(describ)q(es)g(an)g(impro)o(v)o(ed)g(v)o(ersion)f(of)h
(the)g(original)e(single-k)o(ey)i(visa)0 2674 y(proto)q(col)f(\(with)g(state)
g(information)f(in)h(gatew)o(a)o(ys\).)17 b(Section)12 b(4)f(describ)q(es)i
(a)e(stateless)g(v)m(ariation)f(of)i(the)f(single-)964 2828
y(6)p eop
%%Page: 7 7
bop 0 45 a Fp(k)o(ey)19 b(proto)q(col.)29 b(Section)19 b(5)f(presen)o(ts)h
(an)g(ev)m(aluation)f(and)h(analysis)f(of)g(the)h(t)o(w)o(o)e(proto)q(cols.)
30 b(Exp)q(erimen)o(tal)0 102 y(results)14 b(are)h(discussed)g(in)f(section)h
(6.)k(Section)c(7)f(touc)o(hes)h(up)q(on)g(sev)o(eral)f(design)h(issues)f
(that)g(space)h(do)q(es)g(not)0 158 y(p)q(ermit)g(us)g(to)g(co)o(v)o(er)f(in)
h(detail.)k(Finally)l(,)14 b(section)h(8)f(summarizes)h(our)g(\014ndings.)0
340 y Fj(2)69 b(Visa)23 b(proto)r(cols)0 483 y Fr(2.1)56 b(Notation)0
608 y Fp(W)l(e)15 b(use)h(the)f(notation)f(of)h(Needham)g(and)h(Sc)o(hro)q
(eder[)p Fh(?)p Fp(])k(to)14 b(sho)o(w)h(encryption)g(op)q(erations;)f(for)h
(example,)811 664 y Fg(f)p Ff(F)863 671 y Fq(0)882 664 y Ff(;)8
b(F)932 671 y Fq(1)951 664 y Ff(;)g(:::;)g(F)1061 671 y Fe(n)1082
664 y Fg(g)1105 648 y Fe(K)0 721 y Fp(denotes)16 b(the)g(encryption)f(of)g(a)
h(record)f(con)o(taining)f(\014elds)i Ff(F)1067 728 y Fq(0)1103
721 y Fp(through)f Ff(F)1304 728 y Fe(n)1343 721 y Fp(with)g(k)o(ey)h(K.)f(F)
l(or)g(activ)o(e)g(en)o(tities)0 777 y(in)o(v)o(olv)o(ed)e(in)i(the)f(visa)g
(proto)q(cols,)f(w)o(e)h(use)h(the)g(sym)o(b)q(ol)e Fi(H)i
Fp(to)e(denote)i(a)f(host,)g Fi(O)g Fp(to)g(denote)h(an)f(organization,)0
833 y Fi(A)o(CS)e Fp(to)h(denote)g(an)h(Access)g(Con)o(trol)d(Serv)o(er,)j
(and)f Fi(GW)h Fp(to)f(denote)h(an)f(in)o(ter-organization)e(gatew)o(a)o(y)l
(.)18 b Fi(VKEY)0 890 y Fp(denotes)e(a)g(visa)g(k)o(ey)g(issued)h(b)o(y)f(an)
g(A)o(CS)g(for)g(use)g(in)h(creating)e(visas)g(in)i(the)f(stateful)f(visa)h
(proto)q(col,)f(and)h Fi(V)0 946 y Fp(denotes)f(a)g(visa)g(issued)g(b)o(y)g
(an)g(A)o(CS)g(for)g(use)g(in)h(the)f(stateless)f(proto)q(col.)71
1042 y(An)o(y)e(of)f(these)i(sym)o(b)q(ols)e(can)i(b)q(e)f(subscripted)h
Fi(sr)n(c)e Fp(to)h(indicate)g(the)g Fi(sour)n(c)n(e)f Fp(of)h(a)g(datagram,)
f Fi(dst)h Fp(to)f(indicate)0 1098 y(the)k Fi(destination)g
Fp(of)g(a)f(datagram,)g Fi(tr)n(ans)g Fp(to)h(indicate)f(an)h(organization)f
(through)g(whic)o(h)i(a)e(datagram)g(passes)0 1155 y Fi(in)h(tr)n(ansit)e
Fp(b)q(et)o(w)o(een)i(the)f(source)h(and)f(destination)f(organizations,)f
Fi(exit)i Fp(to)g(indicate)g(the)g(gatew)o(a)o(y)f(via)g(whic)o(h)0
1211 y(a)j(datagram)f Fi(exits)i Fp(an)f(organization,)f(and)h
Fi(entr)h Fp(to)f(indicate)g(the)h(gatew)o(a)o(y)d(via)i(whic)o(h)h(a)f
(datagram)f Fi(enters)p Fp(.)0 1268 y(F)l(or)f(example,)g Ff(H)309
1275 y Fe(dst)373 1268 y Fp(denotes)h(the)f(destination)g(host)g(of)g(a)g
(datagram,)f(and)i Ff(GW)1419 1275 y Fe(exit)1496 1268 y Fp(denotes)g(a)f
(visa-gatew)o(a)o(y)0 1324 y(of)h(the)g(source)g(organization)f(through)g
(whic)o(h)h(a)g(datagram)f(lea)o(v)o(es)g(that)h(organization's)e(net)o(w)o
(ork.)0 1485 y Fr(2.2)56 b(Comp)r(onen)n(ts)0 1610 y Fp(Both)15
b(visa)g(proto)q(cols)g(in)o(v)o(olv)o(e)f(the)i(follo)o(wing)d(comp)q(onen)o
(ts:)21 b(visas,)14 b(access)i(con)o(trol)e(serv)o(ers,)h(gatew)o(a)o(ys,)f
(and)0 1666 y(hosts.)19 b(These)d(comp)q(onen)o(ts)f(and)h(their)e(resp)q
(onsibilities)g(are)h(describ)q(ed)h(in)f(this)g(section.)0
1826 y Fh(2.2.1)52 b(Visas)0 1951 y Fp(A)12 b(visa)e(is)h(an)h(unforgeable)f
(stamp,)g(created)h(b)o(y)f(cryptographic)g(means,)h(that)f(is)g(attac)o(hed)
g(to)g(a)g(datagram.)17 b(Its)0 2007 y(presence)e(in)f(a)f(datagram)g
(indicates)g(that)g(the)h(datagram)f(is)g(allo)o(w)o(ed)g(to)g(lea)o(v)o(e)g
(\(or)g(en)o(ter\))g(an)h(organization's)0 2064 y(net)o(w)o(ork.)19
b(A)14 b(visa)g(can)h(b)q(e)g(v)m(alidated)g(b)o(y)f(the)h(gatew)o(a)o(ys)e
(of)h(the)h(organization)d(that)i(issued)h(the)g(visa)f(\(or)g(that)0
2120 y(issued)h(the)h(means)f(for)f(its)h(generation\))711
2103 y Fq(3)729 2120 y Fp(.)20 b(W)l(e)15 b(describ)q(e)h(ho)o(w)f(visa)f(v)m
(alues)i(are)f(computed)g(in)g(section)g Fh(??)p Fp(.)71 2216
y(Eac)o(h)i(datagram)g(carries)g(at)g(most)g(t)o(w)o(o)g(visas)g(-)h(one)g
(\()p Ff(V)1079 2223 y Fe(exit)1141 2216 y Fp(\))g(for)f(en)o(tering)g(and)h
(exiting)f(the)h(source)g(or-)0 2272 y(ganization)c(net)o(w)o(ork,)f(and)i
(one)h(\()p Ff(V)622 2279 y Fe(entr)690 2272 y Fp(\))f(for)f(en)o(tering)h
(and)g(exiting)f(the)h(destination)f(organization)f(net)o(w)o(ork.)0
2328 y(This)h(is)g(necessary)h(b)q(ecause)g(the)g(agen)o(ts)e(of)h(one)h
(organization)d(ma)o(y)i(not)g(trust)g(the)g(agen)o(ts)g(of)g(another)g
(orga-)0 2385 y(nization,)e(so)g(source)g(and)h(destination)e(visas)h(for)g
(a)g(datagram)f(m)o(ust)h(b)q(e)h(issued)f(separately)g(b)o(y)g(the)h(resp)q
(ectiv)o(e)0 2441 y(organizations)265 2425 y Fq(4)283 2441
y Fp(.)p 0 2481 780 2 v 52 2508 a Fl(3)69 2524 y Fk(Estrin)h(and)h(Tsudik[)p
Fd(?)p Fk(])21 b(originally)14 b(used)h(the)f(term)g(\\visa")h(to)f(indicate)
h(the)f(cryptographic)i(k)o(ey)e(used)h(b)o(y)g(the)f(source)h(and)0
2569 y(gatew)o(a)o(y)i(to)f(compute)h(the)g(unforgeable)g(stamp.)27
b(\\Visa")17 b(no)o(w)f(indicates)h(the)f(stamp)h(itself,)f(a)g(usage)h
(closer)g(to)f(the)h(English)0 2615 y(meaning)d(of)e(the)h(w)o(ord.)52
2645 y Fl(4)69 2661 y Fk(In)e(this)g(pap)q(er)h(w)o(e)f(assume)g(the)h(use)f
(of)g Fc(two-way)g(visas)p Fk(;)f(that)h(is,)g(a)g(single)g(visa)g(k)o(ey)g
(is)g(used)h(to)f(generate)h(visas)f(for)g(datagrams)964 2828
y Fp(7)p eop
%%Page: 8 8
bop 71 45 a Fp(F)l(or)15 b(our)i(exp)q(erimen)o(tal)e(mo)q(di\014cation)h(of)
g(the)h(In)o(ternet)f(Proto)q(col)f(\(IP\)[)p Fh(?)p Fp(],)g(visa-related)h
(information)e(is)0 102 y(carried)k(in)g(the)g(OPTIONS)i(\014eld)e(of)g(the)h
(IP)f(header,)h(and)g(so)f(do)q(es)g(not)g(a\013ect)g(the)g(normal)f(pro)q
(cessing)h(of)0 158 y(datagrams)9 b(\(see)i Fh(??)p Fp(\).)17
b(Datagrams)9 b(tra)o(v)o(eling)f(b)q(et)o(w)o(een)j(visa-hosts)f(that)g(do)h
(not)f(require)h(visas)e(\(as)h(decided)i(b)o(y)0 214 y(the)h(A)o(CSs)f(of)h
(eac)o(h)g(organization\))d(con)o(tain)i(dumm)o(y)h(visa)f(v)m(alues)h(in)f
(the)h(appropriate)f(header)h(\014elds)g(to)f(a)o(v)o(oid)0
271 y(calling)17 b(undue)i(atten)o(tion)e(to)h(those)g(datagrams)e(that)i(w)o
(arran)o(t)e(visa)i(protection;)g(only)g(the)g(visa-gatew)o(a)o(ys)0
327 y(kno)o(w)g(whic)o(h)g(datagrams)f(need)i(to)f(con)o(tain)f(v)o
(eri\014ed)i(visas.)28 b(Other)19 b(IP)g(gatew)o(a)o(ys)d(need)j(not)f
(recognize)h(IP)0 384 y(options;)14 b(therefore,)h(visas)f(are)h(transparen)o
(t)f(to)g(non-visa)h(gatew)o(a)o(ys.)71 479 y(A)h(visa)f(k)o(ey)h(is)f(allo)q
(cated)g(to)g(an)h(iden)o(ti\014able)f(source-destination)g(pair.)22
b(In)16 b(this)g(discussion)f(w)o(e)h(assume)0 536 y(that)i(the)h
(uniformly-a)o(v)m(ailable)e(gran)o(ularit)o(y)g(of)h(con)o(trol)g(and)h
(iden)o(ti\014cation)f(is)g(a)h(host;)h(that)e(is,)h(visas)f(are)0
592 y(allo)q(cated)c(for)h(\()p Ff(H)319 599 y Fe(sr)q(c)369
592 y Fp(,)p Ff(H)420 599 y Fe(dst)468 592 y Fp(\))g(pairs.)0
752 y Fh(2.2.2)52 b(A)o(CSs)0 876 y Fp(An)21 b(A)o(CS)g(is)f(a)g(host,)i
(usually)e(dedicated)h(for)f(securit)o(y)g(reasons,)i(that)e(is)g(primarily)f
(concerned)j(with)e(ac-)0 933 y(cess)e(con)o(trol.)27 b(Eac)o(h)17
b(visa-con)o(trolled)g(organization)f(has)h(at)h(least)f(one)h(A)o(CS,)f
(resp)q(onsible)h(for)f(authorizing)0 989 y(hosts)g(within)g(its)g
(organization)f(to)h(comm)o(unicate)h(with)f(hosts)g(in)h(other)f
(organizations)1597 973 y Fq(5)1615 989 y Fp(.)27 b(Multiple)17
b(A)o(CSs)0 1046 y(ma)o(y)h(b)q(e)i(necessary)f(for)f(a)o(v)m(ailabilit)o(y)e
(and)k(p)q(erformance)f(reasons.)30 b(Sp)q(eci\014c)21 b(p)q(olicies)d
(regarding)g(who)h(ma)o(y)0 1102 y(comm)o(unicate)c(with)f(whom)h(are)g(em)o
(b)q(o)q(died)h(within)e(A)o(CSs)h(and)g(are)g(not)g(addressed)h(directly)e
(in)h(this)g(pap)q(er.)71 1198 y(Eac)o(h)d(A)o(CS)g(kno)o(ws)f(of)h(a)g(n)o
(um)o(b)q(er)g(of)g(lo)q(cal)g(visa-gatew)o(a)o(ys)d(that)j(enforce)g(its)g
(decisions.)18 b(A)o(CSs)12 b(are)g(trusted)0 1254 y(and)i(assumed)h(to)e
(defend)j(against)c(attempted)i(abuse.)20 b(The)14 b(securit)o(y)g(of)g(the)g
(o)o(v)o(erall)f(proto)q(col)g(requires)h(that)0 1311 y(A)o(CSs)f(b)q(e)g
(secure)g(and)g(that)g(they)f(emplo)o(y)h(an)f(authen)o(ticated)h(and)g
(secure)g(c)o(hannel)g(for)f(comm)o(unication)g(with)0 1367
y(lo)q(cal)i(hosts)h(and)g(gatew)o(a)o(ys.)0 1526 y Fh(2.2.3)52
b(Gatew)o(a)o(ys)0 1651 y Fp(A)21 b(gatew)o(a)o(y)e(is)i(a)f(host)h
(dedicated)g(\(for)f(reasons)h(of)f(p)q(erformance)h(and)g(securit)o(y\))f
(to)h(pac)o(k)o(et)f(forw)o(arding.)0 1708 y(Gatew)o(a)o(ys)d(that)i(use)g
(the)g(visa)g(mec)o(hanism)f(to)h(enforce)g(access)g(con)o(trols)f(are)h
(called)g(visa-gatew)o(a)o(ys)1829 1691 y Fq(6)1846 1708 y
Fp(.)32 b(All)0 1764 y(in)o(ter-organization)11 b(connections)i(m)o(ust)g(b)q
(e)h(implemen)o(ted)f(with)f(visa-gatew)o(a)o(ys.)17 b(Eac)o(h)c(visa-gatew)o
(a)o(y)f(kno)o(ws)0 1821 y(the)g(A)o(CSs)g(in)g(its)g(organization,)e(is)i
(willing)e(to)i(accept)g(visa)g(assignmen)o(ts)f(from)g(these)h(A)o(CSs,)h
(and)f(trusts)f(their)0 1877 y(decisions)j(ab)q(out)h(authorizing)e(and)i
(terminating)e(sessions.)19 b(A)c(visa-gatew)o(a)o(y)d(allo)o(ws)h(an)o(y)h
(external)g(part)o(y)g(to)0 1934 y(comm)o(unicate)j(with)f(an)o(y)h
(registered,)g(in)o(ternal)f(A)o(CS;)h(similarly)e(the)j(gatew)o(a)o(y)d
(allo)o(ws)h(all)g(registered,)h(lo)q(cal)0 1990 y(A)o(CSs)e(to)g(comm)o
(unicate)f(with)h(an)o(y)f(external)h(part)o(y)928 1974 y Fq(7)947
1990 y Fp(.)71 2086 y(Assuming)21 b(that)g(eac)o(h)h(organization)e(emplo)o
(ys)h(a)g(visa-gatew)o(a)o(y)l(,)g(eac)o(h)h(in)o(ter-organization)d
(datagram)0 2142 y(tra)o(v)o(els)e(through)i(at)f(least)g(t)o(w)o(o)f(suc)o
(h)i(gatew)o(a)o(ys.)29 b(Eac)o(h)18 b(visa-gatew)o(a)o(y)f(is)h(equipp)q(ed)
i(with)e(some)h(means)f(of)p 0 2182 780 2 v 0 2225 a Fk(tra)o(v)o(eling)f(in)
o(to)g(and)h(out)g(of)f(an)g(organization's)h(net)o(w)o(ork)f(b)q(et)o(w)o
(een)h(a)f(particular)g(source-destination)i(pair.)29 b(Ho)o(w)o(ev)o(er,)18
b(if)e(an)0 2270 y(organization)g(w)o(an)o(ts)f(to)g(carry)g(out)g(separate)h
(authorization/authen)o(tication)h(dialogs)e(for)g(incoming)g(and)h(outgoing)
f(tra\016c,)g(it)0 2316 y(ma)o(y)e(do)h(so)f({)g(at)g(the)g(cost)g(of)g
(double)g(the)g(connection)h(setup)g(o)o(v)o(erhead.)52 2346
y Fl(5)69 2362 y Fk(If)e(a)h(participan)o(t)h(organization)g(do)q(es)f(not)h
(ha)o(v)o(e)f(an)g(A)o(CS,)g(its)f(hosts)i(will)d(still)h(b)q(e)h(able)g(to)g
(comm)o(unicate)h(with)e(the)i(hosts)f(of)0 2407 y(other)i(organizations,)g
(although)h(the)e(organization)h(in)g(question)g(will)e(b)q(e)h(sub)r(ject)h
(to)g(risks)f(asso)q(ciated)h(with)f(the)h(uncon)o(trolled)0
2453 y(access.)52 2483 y Fl(6)69 2498 y Fk(Some)d(gatew)o(a)o(ys)g(ma)o(y)g
(not)f(b)q(e)h(in)o(v)o(olv)o(ed)g(in)g(visa-enforcemen)o(t)g(\(for)f
(example,)h(gatew)o(a)o(ys)g(in)o(ternal)f(to)h(an)f(organization\).)18
b(W)m(e)0 2544 y(therefore)13 b(distinguish)h(b)q(et)o(w)o(een)f
Fc(visa-gateways)c Fk(and)14 b Fc(non-visa)d(gateways)p Fk(.)52
2574 y Fl(7)69 2590 y Fk(Suc)o(h)18 b(trust)g(is)e(reasonable)j(b)q(ecause)f
(A)o(CSs)f(are)g(kno)o(wn)h(to)f(b)q(e)h(defensiv)o(e)g(and)f(to)h(enforce)f
(organization)h(p)q(olicy)m(.)30 b(Other)0 2635 y(sp)q(ecial)13
b(serv)o(ers)h(suc)o(h)f(as)g(a)g(name)h(serv)o(er)f(ma)o(y)g(b)q(e)g(giv)o
(en)h(a)f(similar)f(\\carte)h(blanc)o(he")h(for)f(external)g(comm)o
(unication)h(if)e(they)i(to)q(o)0 2681 y(are)f(kno)o(wn)h(to)f(b)q(e)g
(secure.)964 2828 y Fp(8)p eop
%%Page: 9 9
bop 0 45 a Fp(v)o(erifying)15 b(a)i(visa.)23 b(Visa)16 b(proto)q(cols)g
(describ)q(ed)h(in)g(subsequen)o(t)g(sections)f(v)m(ary)h(in)f(the)h
(particular)e(v)m(alidation)0 102 y(tec)o(hniques)g(used.)71
197 y(A)20 b(visa-gatew)o(a)o(y)d(m)o(ust)j(scrutinize)f(ev)o(ery)h(pac)o(k)o
(et)f(it)h(receiv)o(es;)h(datagrams)e(without)g(visas)g(cannot)g(b)q(e)0
254 y(forw)o(arded)h(\(except)h(for)f(those)g(to)g(or)g(from)g(trusted)g(en)o
(tities)g(of)g(the)h(gatew)o(a)o(y's)d(o)o(wn)i(organization\).)34
b(In)0 310 y([)p Fh(?)p Fp(])25 b(w)o(e)17 b(describ)q(e)h(a)f(mec)o(hanism)g
(for)g(a)g(gatew)o(a)o(y)e(to)i(inform)g(a)g(host)f(that)h(visas)f(are)h
(required)h(for)e(an)i(in)o(ter-)0 367 y(organizational)c(connection.)24
b(Datagrams)15 b(m)o(ust)h(b)q(e)h(dropp)q(ed)g(if)g(they)f(con)o(tain)g
(neither)h(a)f(v)m(alid)g(visa)g(nor)g(a)0 423 y(\\dumm)o(y")f(placeholder)g
(visa)f(indicating)g(that)h(a)g(host)f(wishes)h(to)g(b)q(e)h(informed)e(via)h
(this)g(mec)o(hanism.)71 519 y(If)20 b(the)f(t)o(w)o(o)g(organizations')e
(net)o(w)o(orks)i(are)g(not)h(directly)f(connected,)i(pac)o(k)o(ets)e(will)g
(pass)g(through)h(the)0 575 y(gatew)o(a)o(ys)d(of)h(transit)g(net)o(w)o
(orks.)30 b(Visa-gatew)o(a)o(ys)16 b(in)j(a)f(transit)g(net)o(w)o(ork)g
(trust)g(eac)o(h)h(other,)g(and)g(transfer)0 631 y(transit)e(pac)o(k)o(ets)g
(via)g(secure)i(c)o(hannels)f(to)f(prev)o(en)o(t)h(unauthorized)g(en)o
(trance)g(or)f(exit;)h(this)g(is)f(describ)q(ed)i(in)0 688
y(more)c(detail)g(in)h([)p Fh(?)p Fp(].)k(Non-visa)15 b(gatew)o(a)o(ys)f(in)i
(transit)e(net)o(w)o(orks)h(treat)f(visa)h(datagrams)f(as)i(regular)f(in)o
(ternet)0 744 y(pac)o(k)o(ets.)0 904 y Fh(2.2.4)52 b(Hosts)0
1029 y Fp(The)13 b(source)f(host)g(\()p Ff(H)379 1036 y Fe(sr)q(c)429
1029 y Fp(\))g(of)g(an)g(in)o(ter-organization)e(connection)j(m)o(ust)f
(obtain)f(a)h(pair)g(of)g(visas,)g(one)g(from)g(the)0 1085
y(A)o(CS)i(of)g(its)f(organization)f(\()p Ff(AC)s(S)592 1092
y Fe(sr)q(c)643 1085 y Fp(\))i(and)h(one)f(from)f(the)i(A)o(CS)f(of)f(the)i
(destination)e(organization)f(\()p Ff(AC)s(S)1870 1092 y Fe(dst)1920
1085 y Fp(\).)0 1141 y(These)18 b(visas)f(m)o(ust)g(b)q(e)h(included)g(in)f
(the)h(header)g(of)f(ev)o(ery)h(datagram)e(sen)o(t)h(from)g
Ff(H)1524 1148 y Fe(sr)q(c)1592 1141 y Fp(to)f(the)i(destination)0
1198 y(host,)c Ff(H)149 1205 y Fe(dst)198 1198 y Fp(.)71 1294
y(A)h(host,)f(unlik)o(e)h(a)g(gatew)o(a)o(y)l(,)f(do)q(es)h(not)g(ha)o(v)o(e)
g(to)g(ha)o(v)o(e)g(reliable)f(kno)o(wledge)h(of)g(the)g(lo)q(cal)g(A)o(CS's)
f(address;)0 1350 y(this)22 b(ma)o(y)g(instead)g(b)q(e)h(supplied)g(b)o(y)g
(a)f(gatew)o(a)o(y)f(when)i(a)f(host)h(attempts)e(to)h(comm)o(unicate)g
(across)g(the)0 1406 y(organizational)12 b(b)q(oundary)i(\(see)h([)p
Fh(?)p Fp(]\).)j(The)c(host)g(m)o(ust)g(still)f(use)h(an)g(authen)o(tication)
f(proto)q(col)g(to)h(mak)o(e)g(sure)0 1463 y(it)g(is)h(really)f(talking)g(to)
h(the)g(A)o(CS.)71 1558 y(Since)h(datagram)e(reception)i(is)g(a)f(passiv)o(e)
g(op)q(eration,)g(the)h(destination)f(host)g(\()p Ff(H)1520
1565 y Fe(dst)1569 1558 y Fp(\))h(is)f(not)h(required)g(to)0
1615 y(initiate)e(an)o(y)h(actions.)k(Of)d(course,)f(in)g(almost)f(an)o(y)h
(proto)q(col,)f(datagrams)f(\015o)o(w)i(in)g(b)q(oth)h(directions,)e(so)h
(eac)o(h)0 1671 y(host)e(is)g(b)q(oth)g(a)g(source)h(and)f(a)g(destination.)
18 b(Therefore,)c(to)e(a)o(v)o(oid)g(additional)g(o)o(v)o(erhead)h(w)o(e)g
(assume)g(that)g(an)0 1728 y(organization)f(allo)o(ws)f(its)i(A)o(CS)g(to)g
(allo)q(cate)f Fi(two-way)j Fp(visas)e(automatically)e Fi(if)i
Fp(authen)o(tication)f(of)h(the)h(remote)0 1784 y(destination)g(is)h(not)g
(required.)71 1880 y(By)i(themselv)o(es,)h(visa)f(proto)q(cols)f(do)i(not)f
(pro)o(vide)h(for)f(m)o(ulti-lev)o(el)f(securit)o(y)l(,)h(nor)g(do)h(they)g
(eliminate)e(a)0 1936 y(v)m(ariet)o(y)h(of)g(co)o(v)o(ert)g(c)o(hannels.)27
b(In)19 b(the)f(absence)g(of)f(additional)f(host-lev)o(el,)i
(non-discretionary)e(con)o(trols,)h(an)0 1993 y(authorized)e(host)f(ma)o(y)g
(still)f(sub)o(v)o(ert)i(these)g(proto)q(cols)f(b)o(y)h(\\willingly")d
(serving)i(as)h(a)f(conduit)h(for)f(comm)o(uni-)0 2049 y(cations)g(b)q(et)o
(w)o(een)i(unauthorized)f(hosts.)0 2210 y Fr(2.3)56 b(Establishing)17
b(authorization)0 2335 y Fp(In)e(the)f(sc)o(heme)g(originally)e(prop)q(osed)i
(in)g([)p Fh(?)p Fp(],)e Ff(H)845 2342 y Fe(sr)q(c)896 2335
y Fp(,)i(when)g(op)q(ening)g(a)g(connection)g(to)f Ff(H)1564
2342 y Fe(dst)1613 2335 y Fp(,)h(initially)e(sends)i(a)0 2392
y(datagram)g(with)h(an)h(\\empt)o(y")f(visa;)g(if)g(the)h(datagram)e(reac)o
(hes)i(a)f(visa-gatew)o(a)o(y)l(,)e(the)j(gatew)o(a)o(y)e(replies)i(with)0
2448 y(a)h(REJECT)h(message)f(directing)f Ff(H)648 2455 y Fe(sr)q(c)716
2448 y Fp(to)h(an)g(appropriate)f(A)o(CS.)h(The)h(source)f(host)g(requests)g
(a)g(visa)g(from)0 2504 y(that)i(A)o(CS,)g(whic)o(h)g(\(if)g(necessary\))h
(obtains)e(visas)h(from)g(A)o(CSs)g(in)h(other)f(organizations,)f
(distributes)h(visa)0 2561 y(information)13 b(to)h(the)h(appropriate)f(gatew)
o(a)o(ys,)f(and)i(returns)g(the)g(v)m(alid)f(visas)g(to)h Ff(H)1466
2568 y Fe(sr)q(c)1531 2561 y Fp(\(and,)f(p)q(ossibly)l(,)h
Ff(H)1871 2568 y Fe(dst)1920 2561 y Fp(\).)0 2617 y(The)i(purp)q(ose)g(of)f
(the)h(REJECT)g(mec)o(hanism)f(is)g(to)g(accommo)q(date)g(hosts)g(that)g(do)h
(not)f(kno)o(w)g(when)h(a)g(visa)0 2674 y(is)e(required.)964
2828 y(9)p eop
%%Page: 10 10
bop 71 45 a Fp(Ho)o(w)o(ev)o(er,)15 b(a)g(host)h(ma)o(y)f(already)h(kno)o(w)f
(that)h(its)f(in)o(tended)i(destination)e(is)g(in)h(a)g(di\013eren)o(t)f
(organization,)0 102 y(either)i(b)q(ecause)h(it)f(has)g(previously)g(comm)o
(unicated)g(with)f(that)h(host)g(\(and)g(cac)o(hed)h(the)f(fact)g(that)g(at)f
(some)0 158 y(p)q(oin)o(t)c(it)g(had)h(receiv)o(ed)g(a)g(REJECT\),)f(or)g(it)
g(ma)o(y)g(ha)o(v)o(e)h(disco)o(v)o(ered)f(this)g(through)h(some)f(external)g
(mec)o(hanism)0 214 y(\(for)19 b(example,)h(a)g(name)g(serv)o(er\).)33
b(If)20 b(so,)g(it)f(ma)o(y)g(comm)o(unicate)g(immediately)g(with)g(an)g(A)o
(CS)h(of)f(its)g(o)o(wn)0 271 y(organization)d(to)i(obtain)g(visas,)g(rather)
f(than)i(going)e(through)h(the)h(extra)e(t)o(w)o(o-pac)o(k)o(et)g(step)h(of)g
(attempting)0 327 y(to)f(send)i(the)f(initial)e(datagram)g(and)j(receiving)e
(a)h(REJECT.)g(The)g(REJECT)g(mec)o(hanism)g(is)f(a)h(\\fallbac)o(k")0
384 y(mec)o(hanism)j(to)g(inform)g(hosts)h(that)f(they)g(are)h(crossing)f(an)
g(organizational)f(b)q(oundary)l(,)j(rather)e(than)h(an)0 440
y(in)o(tegral)16 b(part)g(of)h(connection)g(setup.)27 b(Note)17
b(that)f(a)h(REJECT)h(ma)o(y)e(actually)g(b)q(e)i(sen)o(t)f(in)g(the)g
(middle)g(of)g(a)0 497 y(connection,)c(if)g(a)g(visa)g(expires)g(or)g(if)g(a)
g(gatew)o(a)o(y)f(table)h(o)o(v)o(er\015o)o(ws)f(and)h(activ)o(e)g(visas)g
(are)g(purged.)19 b(F)l(or)13 b(further)0 553 y(detail)h(on)h(the)h(REJECT)f
(mec)o(hanism)g(see)g([)p Fh(?)p Fp(].)71 649 y(Man)o(y)c(in)o
(ter-organizational)e(connections)j(are)f(brief:)18 b(in)12
b(the)g(In)o(ternet,)g(for)g(example,)g(most)f(suc)o(h)h(connec-)0
705 y(tions)k(are)g(either)h(electronic)f(mail)f(transfers,)h(whic)o(h)h
(usually)f(in)o(v)o(olv)o(e)f(no)i(more)f(than)g(a)h(dozen)g(datagrams,)0
762 y(or)i(name)g(translations,)e(whic)o(h)i(are)g(ev)o(en)g(briefer.)31
b(A)19 b(visa)f(authorizes)h(datagram)e(transmission)h(b)q(et)o(w)o(een)0
818 y(t)o(w)o(o)12 b(hosts,)i(not)f(a)h(sp)q(eci\014c)g(high-lev)o(el)f
(connection.)20 b(Therefore,)14 b(w)o(e)f(do)h(not)f(require)h(hosts)f(to)g
(obtain)g(a)h(fresh)0 875 y(visa)j(for)g(ev)o(ery)h(connection,)g(nor)f(do)h
(w)o(e)g(exp)q(ect)g(hosts)f(to)g(inform)g(the)h(gatew)o(a)o(ys)e(when)i(a)g
(visa-con)o(trolled)0 931 y(connection)d(terminates.)20 b(\\Least-recen)o
(tly-used")15 b(mec)o(hanisms)g(can)h(k)o(eep)g(gatew)o(a)o(y)d(cac)o(hes)j
(or)f(tables)g(from)0 988 y(\014lling)h(with)h(stale)f(data.)26
b(W)l(e)17 b(rely)g(up)q(on)h(the)g(A)o(CSs)f(to)f(enforce)i(sp)q(eci\014c)g
(visa)e(expiration)h(and)g(rev)o(o)q(cation)0 1044 y(p)q(olicies.)0
1205 y Fr(2.4)56 b(Computing)18 b(visa)g(v)m(alues)0 1330 y
Fp(A)e(visa)g(v)m(alue)g(m)o(ust)g(protect)g(against)e(sub)o(v)o(ersion)i(in)
g(t)o(w)o(o)f(w)o(a)o(ys.)22 b(First,)15 b(it)g(m)o(ust)h(pro)o(v)o(e)f(that)
h(the)g(source)g(of)0 1386 y(a)g(datagram)f(is)h(authorized)g(to)g(send)h
(datagrams)e(to)g(the)i(destination)e(\(in)h(other)g(w)o(ords,)g(that)f(an)i
(imp)q(oster)0 1443 y(cannot)e(p)q(ose)h(as)f(an)g(authorized)h(source)f
(merely)g(b)o(y)h(faking)e(its)h(in)o(ternet)g(address\).)20
b(Second,)c(it)f(m)o(ust)g(pro)o(v)o(e)0 1499 y(that)h(the)h(particular)e
(data)h(carried)g(in)h(a)f(datagram)f(is)i(the)f(same)h(data)f(that)g(the)g
(source)h(in)o(tended)g(to)f(send)0 1556 y(to)e(the)h(destination.)k(W)l(e)c
(refer)g(to)f(this)g(second)i(pro)q(of)e(as)h(\\data)f(in)o(tegrit)o(y)l(.")j
(In)f(general,)e(transformation)e(of)0 1612 y(a)j(data)f(v)m(alue)i(to)e
(guaran)o(tee)h(its)f(pro)o(v)o(enance)h(is)g(kno)o(wn)g(as)g(a)g(\\digital)e
(signature"[)p Fh(?)p Fp(,)g Fh(?)p Fp(,)h Fh(?)p Fp(].)71
1708 y(The)f(in)o(tegrit)o(y)f(of)h(a)g(visa)g(proto)q(col)f(dep)q(ends)j(on)
f(the)f(metho)q(d)h(b)o(y)f(whic)o(h)h(the)f(visa)g(v)m(alues)h(are)f
(calculated.)0 1764 y(T)l(o)e(a)o(v)o(oid)f(\\pla)o(ybac)o(k)h(attac)o(ks",)f
(a)h(visa)g(v)m(alue)g(m)o(ust)g(b)q(e)h(deriv)o(ed)g(from)e(a)i(visa)e(k)o
(ey)i(and)f(some)g(unique)h(prop)q(ert)o(y)0 1821 y(of)22 b(eac)o(h)g
(individual)g(datagram.)39 b(In)23 b(other)f(w)o(ords,)h Ff(v)r(isa)h
Fp(=)h Ff(F)6 b Fp(\()p Ff(v)r(isak)q(ey)r(;)i(datag)r(r)q(am)p
Fp(\))20 b(where)j(F)e(is)h(some)0 1877 y(cryptographically)e(strong)h(one-w)
o(a)o(y)g(\(trap)q(do)q(or\))g(function)h(that)f(computes)h(a)g
(cryptographic)f(signature)0 1933 y(of)g(the)g(datagram.)37
b(The)22 b(function)f(c)o(hosen)g(for)g(F)g(m)o(ust)g(ha)o(v)o(e)g(go)q(o)q
(d)g(cryptographic)f(prop)q(erties,)i(y)o(et)f(b)q(e)0 1990
y(inexp)q(ensiv)o(e)f(to)e(compute.)33 b(In)20 b(this)f(pap)q(er,)h(w)o(e)f
(assume)g(that)g Ff(F)26 b Fp(is)18 b(a)h(function)h(suc)o(h)f(as)g(the)h
(DES-based)0 2046 y(Message)15 b(Authen)o(tication)f(Co)q(de)h(\(MA)o(C\)[)p
Fh(?)p Fp(].)71 2142 y(Note)j(that)g(the)i(sizes)e(of)h(b)q(oth)g(visas)f
(and)h(visa)g(k)o(eys)f(a\013ect)h(the)g(cost)f(of)h(computing)f(visas;)i
(they)f(also)0 2198 y(a\013ect)e(the)g(lik)o(eliho)q(o)q(d)f(that)h(a)g(visa)
g(system)g(can)g(b)q(e)h(compromised.)26 b(Unfortunately)l(,)17
b(although)g(signatures)0 2255 y(and)d(k)o(eys)g(with)g(larger)f(sizes)h(are)
g(more)f(resistan)o(t)g(to)g(attac)o(k,)g(they)h(also)f(increase)i(the)f
(cost)f(of)h(computing)g Ff(F)6 b Fp(.)0 2437 y Fj(3)69 b(Single-k)n(ey)22
b(proto)r(col)g(with)g(state)g(information)g(in)h(gatew)n(a)n(ys)0
2578 y Fp(This)f(section)g(describ)q(es)h(the)g(\014rst)f(single-k)o(ey)f(v)m
(ariation)g(of)h(the)h(visa)e(proto)q(col,)i(deriv)o(ed)g(from)e(the)i(one)0
2634 y(prop)q(osed)11 b(in)f([)p Fh(?)p Fp(].)17 b(In)10 b(this)g(proto)q
(col,)g(all)f(non-transit)g(visa-gatew)o(a)o(ys)f(along)h(all)g(p)q(ossible)h
(routes)g(of)g(a)f(datagram)0 2691 y(m)o(ust)k(con)o(tain)f(an)h(appropriate)
f(en)o(try)h(in)f(their)h(tables.)19 b(Therefore,)13 b(in)g(order)f(to)h(set)
g(up)g(a)g(path)g(b)q(et)o(w)o(een)g(t)o(w)o(o)952 2828 y(10)p
eop
%%Page: 11 11
bop 0 45 a Fp(hosts,)13 b(eac)o(h)i(suc)o(h)f(gatew)o(a)o(y)e(m)o(ust)i(comm)
o(unicate)f(with)h(its)f(organization's)f(A)o(CS)h(to)h(obtain)f(the)h(visa)g
(k)o(ey)g(for)0 102 y(the)h(source-destination)g(pair.)71 197
y(This)f(is)f(the)i(distinctiv)o(e)e(feature)h(that)g(separates)g(this)f
(proto)q(col)h(from)f(the)i(stateless)e(proto)q(col)g(discussed)0
254 y(later)g(in)i(the)f(pap)q(er.)20 b(Here,)15 b(eac)o(h)g(comp)q(onen)o(t)
f(\(hosts,)g(A)o(CSs,)g(and)g(gatew)o(a)o(ys\))f(m)o(ust)h(main)o(tain)f(a)h
Fi(visa-table)p Fp(,)0 310 y(a)h(database)g(of)f(activ)o(e)h(visa)f
(information.)k(An)e(en)o(try)e(in)h(the)h(visa-table)e(p)q(ertains)h(to)f
(the)h(state)g(information)0 367 y(of)h(a)h(sp)q(eci\014c)g(in)o
(ter-organization)e(connection.)24 b(In)17 b(the)g(stateless)f(proto)q(col,)g
(in)g(return)h(for)f(sligh)o(tly)f(greater)0 423 y(p)q(er-pac)o(k)o(et)d
(header)g(length)g(and)g(encryption)g(o)o(v)o(erhead,)g(only)g(the)g(hosts)f
(m)o(ust)h(main)o(tain)e(reliable)h(databases.)0 479 y(The)16
b(stateless-proto)q(col)f(gatew)o(a)o(ys)f(use)i(cac)o(hes)h(to)e(impro)o(v)o
(e)g(their)h(p)q(erformance,)g(without)f(requiring)h(extra)0
536 y(pac)o(k)o(et)f(exc)o(hanges)g(for)g(database)f(main)o(tenance.)0
697 y Fr(3.1)56 b(Creation)18 b(and)h(distribution)f(of)h(visa)f(k)n(eys)0
822 y Fp(In)e(this)e(v)m(arian)o(t,)f(a)i Fi(visa)h(key)e Fp(is)h(a)f(unique)
i(v)m(alue)f(\(a)f(cryptographic)g(k)o(ey\))h(assigned)f(b)o(y)h(an)g(A)o(CS)
g(to)f(a)g(session)0 878 y(b)q(et)o(w)o(een)i(t)o(w)o(o)f(hosts)g(on)h
(distinct)f(net)o(w)o(orks.)20 b(The)c(visa)f(v)m(alue)h(carried)g(in)f(the)h
(datagram)e(is)i(computed)g(as)f(a)0 935 y(cryptographic)f(signature)h(of)g
(a)f(datagram.)71 1030 y(Whenev)o(er)j(an)g(A)o(CS)g(issues)g(a)g(visa)f(k)o
(ey)h(to)g(a)g(host)f(via)h(a)g(VISA)o(GRANT)g(message,)g(it)g(m)o(ust)f
(also)g(send)0 1087 y(the)h(visa)g(k)o(ey)g(to)g(all)f(the)i(b)q(order)g
(visa-gatew)o(a)o(ys)d(for)h(the)i(organization.)24 b(If)18
b(there)f(is)g(more)g(than)h(one)f(A)o(CS)0 1143 y(for)e(an)h(organization,)e
(it)h(migh)o(t)f(also)h(b)q(e)i(useful)f(to)f(distribute)g(the)h(visa)f
(information)f(to)h(other)g(A)o(CSs)h(so)f(as)0 1200 y(to)g(impro)o(v)o(e)f
(the)h(a)o(v)m(ailabilit)o(y)d(of)j(the)g(information)f(in)h(the)g(case)g(of)
g(host)g(failures)1452 1183 y Fq(8)1472 1200 y Fp(.)0 1360
y Fr(3.2)56 b(V)-5 b(eri\014cation)18 b(of)h(visas)0 1485 y
Fp(Once)d(the)f(visa)f(k)o(eys)h(are)f(in)h(place,)g Ff(H)681
1492 y Fe(sr)q(c)746 1485 y Fp(is)f(able)h(to)f(send)i(datagrams)d(to)i
Ff(H)1362 1492 y Fe(dst)1411 1485 y Fp(.)k(Ev)o(ery)c(outgoing)e(datagram)0
1542 y(addressed)k(to)f Ff(H)304 1549 y Fe(dst)370 1542 y Fp(is)h(stamp)q(ed)
g(with)f(b)q(oth)h(exit)f(and)h(en)o(trance)g(visas,)f Ff(V)1335
1549 y Fe(exit)1414 1542 y Fp(and)h Ff(V)1531 1549 y Fe(entr)1600
1542 y Fp(.)25 b(Both)16 b(v)m(alues)h(are)0 1598 y(calculated)11
b(as)h(describ)q(ed)g(ab)q(o)o(v)o(e.)19 b Ff(GW)686 1605 y
Fe(exit)760 1598 y Fp(and)12 b Ff(GW)924 1605 y Fe(entr)1005
1598 y Fp(eac)o(h)g(calculate)f Ff(V)1317 1605 y Fe(exit)1391
1598 y Fp(and)h Ff(V)1503 1605 y Fe(entr)1584 1598 y Fp(resp)q(ectiv)o(ely)g
(\(using)0 1655 y(the)19 b(v)m(alues)f Ff(V)10 b(K)s(E)s(Y)362
1662 y Fe(exit)443 1655 y Fp(and)19 b Ff(V)9 b(K)s(E)s(Y)676
1662 y Fe(entr)764 1655 y Fp(from)17 b(their)h(visa-tables\),)g(and)h
(compare)f(them)g(with)g(the)h(v)m(alues)0 1711 y(found)13
b(in)f(the)g(datagram.)17 b(If)c(the)f(t)o(w)o(o)f(v)m(alues)h(matc)o(h,)g
(the)h(datagram)d(is)i(passed,)h(otherwise)e(it)h(is)f(REJECT)l(ed.)0
1768 y(This)j(pro)q(cedure)i(sim)o(ultaneously)d(v)o(eri\014es)i(that)f(a)g
(visa)g(is)g(v)m(alid,)g(that)g(a)h(visa)f(allo)o(ws)f Ff(H)1569
1775 y Fe(sr)q(c)1634 1768 y Fp(to)h(comm)o(unicate)0 1824
y(with)h Ff(H)142 1831 y Fe(dst)191 1824 y Fp(,)f(and)i(that)e(the)i(con)o
(ten)o(ts)e(of)h(a)g(datagram)e(are)i(those)g(that)g(w)o(ere)g(sen)o(t)g(b)o
(y)g Ff(H)1552 1831 y Fe(sr)q(c)1602 1824 y Fp(.)0 1985 y Fr(3.3)56
b(Connection)18 b(rev)n(o)r(cation)0 2110 y Fp(Because)c(man)o(y)g(proto)q
(cols)e(do)i(not)g(ha)o(v)o(e)f(an)h(explicit)f(ending)h(phase)g(\(for)e
(example,)i(the)g(delta-T)f(proto)q(col[)p Fh(?)p Fp(,)0 2166
y Fh(?)p Fp(]\))21 b(an)15 b(A)o(CS)h(imp)q(oses)f(time)g(limits)f(on)i
(visas)f(that)g(it)g(issues.)21 b(The)16 b(time)f(limits)f(are)h(passed)h
(along)f(with)g(the)0 2223 y(visa)h(k)o(eys)g(to)g(the)h(lo)q(cal)f
(visa-gatew)o(a)o(ys,)e(whic)o(h)j(delete)f(the)h(connection's)g(en)o(try)f
(from)g(their)g(visa-tables)f(as)0 2279 y(so)q(on)i(as)g(the)g(connection)g
(times)g(out.)25 b(A)18 b(host)e(that)h(an)o(ticipates)f(exceeding)h(the)h
(time-limit)d(of)i(its)f(curren)o(t)0 2336 y(visa)h(ma)o(y)g(request)h(a)g
(visa)f(extension)h(b)q(efore)g(the)g(visa)g(expires,)g(in)g(order)f(to)h(a)o
(v)o(oid)e(reapplication)h(dela)o(ys.)0 2392 y(In)k(addition)e(to)h(exceeded)
h(time)f(or)g(resource)g(limits,)f(a)h(REV)o(OKE)h(message)f(ma)o(y)f(b)q(e)i
(used)g(to)f(rev)o(ok)o(e)f(a)0 2449 y(visa.)g(A)c(REV)o(OKE)g(message,)f
(triggered)g(b)o(y)h(a)f(request)h(from)f Ff(H)1154 2456 y
Fe(sr)q(c)1204 2449 y Fp(,)h Ff(H)1270 2456 y Fe(dst)1319 2449
y Fp(,)f(or)g(an)h(A)o(CS)g(itself,)e(is)h(sen)o(t)h(to)f(the)0
2505 y(appropriate)f(gatew)o(a)o(ys)e(b)o(y)j(the)g(A)o(CS.)f(The)h(system)f
(is)g(vulnerable)g(to)g(the)h(exten)o(t)f(that)g(REV)o(OKE)h(messages)0
2562 y(ma)o(y)g(b)q(e)i(dropp)q(ed)h(or)d(dela)o(y)o(ed.)p
0 2601 780 2 v 52 2628 a Fl(8)69 2644 y Fk(If)g(one-w)o(a)o(y)h(visas)g(are)g
(used,)g(this)g(same)g(pro)q(cedure)h(will)d(b)q(e)i(carried)g(out)g(in)g
(rev)o(erse)g(when)g(the)f(\014rst)h(return)h(datagram)f(is)0
2690 y(generated.)952 2828 y Fp(11)p eop
%%Page: 12 12
bop 0 45 a Fr(3.4)56 b(Problems)0 170 y Fp(The)19 b(main)f(dra)o(wbac)o(k)f
(of)h(this)g(proto)q(col)g(is)g(that)g(eac)o(h)g(visa-gatew)o(a)o(y)e(b)q(et)
o(w)o(een)j(a)f(pair)g(of)g(comm)o(unicating)0 227 y(hosts)d(m)o(ust)f
(include)i(a)f(visa-table)f(en)o(try)h(for)f(that)h(host-pair.)k(This)14
b(is)h(undesirable)g(b)q(ecause:)68 372 y Fg(\017)23 b Fp(The)f(setup)f(mec)o
(hanism)h(used)g(to)f(get)g(visas)g(in)o(to)g(the)g(visa-tables)g(generates)g
(a)g(n)o(um)o(b)q(er)h(of)g(extra)114 428 y(datagrams.)h(A)o(t)16
b(least)g(t)o(w)o(o)f(visas)h(m)o(ust)g(b)q(e)i(sen)o(t)e(from)g(A)o(CSs)h
(to)f(gatew)o(a)o(ys,)f(requiring)h(at)g(least)g(that)114 485
y(man)o(y)e(datagrams)446 468 y Fq(9)465 485 y Fp(.)68 579
y Fg(\017)23 b Fp(One)14 b(of)g(the)g(commonly-held)g(adv)m(an)o(tages)f(of)h
(datagram)e(net)o(w)o(orks)h(is)g(their)h(abilit)o(y)e(to)h(e\016cien)o(tly)h
(and)114 635 y(dynamically)k(switc)o(h)g(pac)o(k)o(ets)h(along)g(m)o(ultiple)
f(routes,)h(th)o(us)h(pro)o(viding)e(some)h(imm)o(unit)o(y)f(to)h(failed)114
692 y(gatew)o(a)o(ys)g(or)h(links,)h(and)g(spreading)g(load)f(across)g(the)h
(a)o(v)m(ailable)f(bandwidth)h(of)f(a)h(w)o(ell-connected)114
748 y(net)o(w)o(ork.)32 b(In)21 b(order)e(to)h(tak)o(e)f(adv)m(an)o(tage)g
(of)h(routing)e(redundancy)j(when)g(using)e(visas,)h(ev)o(ery)g(lo)q(cal)114
804 y(visa-gatew)o(a)o(y)d(along)i(an)o(y)g(p)q(oten)o(tial)g(route)g(is)h
(giv)o(en)f(the)h(visa)f(information)f(at)h(setup)h(time,)g(whic)o(h)114
861 y(can)c(p)q(oten)o(tially)f(result)h(in)g(\()p Ff(M)g Fp(+)11
b Ff(N)5 b Fp(\))15 b(datagrams)g(to)h(b)q(e)h(sen)o(t)f(b)o(y)h(source's)f
(and)g(destination's)f(A)o(CSs)114 917 y(to)i(their)g(resp)q(ectiv)o(e)g
(visa-gatew)o(a)o(ys)e(\(M)i(and)h(N)g(are)f(the)g(n)o(um)o(b)q(er)h(of)g
(visa-gatew)o(a)o(ys)d(in)i(eac)o(h)h(of)f(the)114 974 y(organizations')12
b(net)o(w)o(orks\).)68 1068 y Fg(\017)23 b Fp(A)18 b(gatew)o(a)o(y)f(m)o(ust)
h(main)o(tain)f(its)h(visa-table,)g(whic)o(h)h(can)f(p)q(oten)o(tially)f(b)q
(e)j(quite)e(large)g(\()p Ff(O)q Fp(\()p Ff(n)p Fp(\))f(in)i(the)114
1124 y(n)o(um)o(b)q(er)d(of)g(comm)o(unicating)f(host)g(pairs\).)22
b(T)l(able)16 b(o)o(v)o(er\015o)o(w)f(is)h(not)f(fatal,)g(but)h(when)h(a)f
(purged)g(en)o(try)114 1181 y(turns)d(out)f(to)h(b)q(e)g(activ)o(e,)g(part)f
(of)h(the)g(setup)g(mec)o(hanism)g(m)o(ust)f(b)q(e)i(rein)o(v)o(ok)o(ed.)k
(The)c(storage)d(o)o(v)o(erhead)114 1237 y(of)h(visa-tables)g(is)g(p)q(er)i
(visa-gatew)o(a)o(y)l(,)d(not)h(simply)h(p)q(er)g(gatew)o(a)o(y-pair,)e
(since)i(the)g(t)o(w)o(o)f(gatew)o(a)o(ys)f(b)q(elong)114 1293
y(to)j(di\013eren)o(t)h(organizations)e(and)i(cannot)g(trust)g(one)g
(another.)68 1387 y Fg(\017)23 b Fp(When)12 b(a)g(visa-gatew)o(a)o(y)d
(crashes,)j(unless)h(its)e(visa-table)g(is)g(held)h(in)g(stable)f(storage)g
(it)g(m)o(ust)h(b)q(e)g(reloaded)114 1444 y(from)21 b(the)h(organization's)e
(A)o(CS.)i(If)h(the)f(A)o(CS)g(crashes)g(as)g(w)o(ell,)h(the)f(setup)h(mec)o
(hanism)f(m)o(ust)f(b)q(e)114 1500 y(rein)o(v)o(ok)o(ed)f(for)g(ev)o(ery)h
(activ)o(e)f(connection.)37 b(The)21 b(resulting)f(burst)h(in)g(o)o(v)o
(erhead)f(tra\016c)g(is)h(lik)o(ely)f(to)114 1557 y(create)15
b(congestion.)0 1739 y Fj(4)69 b(Stateless)21 b(single-k)n(ey)h(proto)r(col)0
1880 y Fp(In)d(order)g(to)f(a)o(v)o(oid)f(some)h(of)g(the)h(problems)f
(listed)g(in)h(section)f Fh(??)p Fp(,)g(w)o(e)g(presen)o(t)h(a)f(di\013eren)o
(t)g(visa)g(proto)q(col)0 1936 y(without)d(the)g(requiremen)o(t)h(that)f(the)
g(gatew)o(a)o(ys)f(kno)o(w)h(ab)q(out)h(ev)o(ery)f(visa.)21
b(This)15 b(means)h(that)f(w)o(e)g(no)h(longer)0 1993 y(ha)o(v)o(e)j(to)g(pa)
o(y)g(the)g(costs)g(for)f(setting)h(up)g(and)h(storing)e(visa-tables,)h
(although)f(the)i(p)q(er-pac)o(k)o(et)f(pro)q(cessing)0 2049
y(costs)c(are)g(sligh)o(tly)e(higher,)h(and)i(rev)o(o)q(cation)e(is)h(more)f
(disruptiv)o(e.)71 2145 y(The)g(primary)g(di\013erence)g(b)q(et)o(w)o(een)h
(the)g(t)o(w)o(o)e(proto)q(cols)g(is)h(where)h(the)f(gatew)o(a)o(ys)f(\014nd)
i(the)g(authorization)0 2201 y(information.)j(In)e(the)f(\014rst,)g(or)f
Fi(stateful)h Fp(proto)q(col,)f(a)h(gatew)o(a)o(y)f(k)o(eeps)h(all)f
(authorization)g(information)f(ab)q(out)0 2257 y(activ)o(e)i(connections)i
(in)f(its)f(visa-table,)g(whic)o(h)h(m)o(ust)g(b)q(e)h(loaded)f(b)o(y)g(the)g
(A)o(CS.)g(In)h(the)f(second,)h(or)e Fi(stateless)0 2314 y
Fp(proto)q(col,)22 b(the)f(authorization)f(information)g(is)h(attac)o(hed)g
(b)o(y)g(cryptographic)g(means)g(to)g(eac)o(h)h(datagram;)0
2370 y(a)g(gatew)o(a)o(y)e(needs)j(no)f(authorization)e(database.)40
b(In)22 b(e\013ect,)i(the)e(visa)f(information)f(is)i(piggybac)o(k)o(ed)f(on)
0 2427 y(eac)o(h)d(datagram)e(rather)h(than)h(b)q(eing)g(directly)f(comm)o
(unicated)g(b)q(et)o(w)o(een)i(A)o(CSs)e(and)h(gatew)o(a)o(ys.)26
b(A)18 b(digital)0 2483 y(signature)d(system)g(is)g(used)h(to)f(main)o(tain)f
(the)i(in)o(tegrit)o(y)e(of)h(this)g(piggybac)o(k)o(ed)g(information,)e(and)j
(cac)o(hing)f(is)0 2540 y(used)h(to)e(reduce)i(the)g(amoun)o(t)e(of)h
(encryption)g(o)o(v)o(erhead.)p 0 2579 780 2 v 52 2606 a Fl(9)69
2622 y Fk(This)d(is)g(in)g(addition)h(to)f(whatev)o(er)h(datagrams)g(need)g
(b)q(e)g(exc)o(hanged)h(b)q(et)o(w)o(een)f(the)f(source)h(host)g(and)g(the)f
(A)o(CSs)g(in)o(v)o(olv)o(ed)h(in)0 2668 y(order)g(to)g(authorize)h(the)f
(visas.)952 2828 y Fp(12)p eop
%%Page: 13 13
bop 71 45 a Fp(The)21 b(particular)e(proto)q(col)h(describ)q(ed)i(here)g
(uses)f(a)f(single-k)o(ey)h(\(priv)m(ate-k)o(ey\))f(cryptosystem)g(suc)o(h)h
(as)0 102 y(DES[)p Fh(?)p Fp(].)e(A)c(public-k)o(ey)g(v)o(ersion)g(is)f
(quite)h(similar;)e(see)j([)p Fh(?)p Fp(].)0 262 y Fr(4.1)56
b(Ov)n(erview)17 b(of)i(the)f(stateless)g(mec)n(hanism)0 387
y Fp(Supp)q(ose)13 b(that)e Ff(H)308 394 y Fe(sr)q(c)370 387
y Fp(in)g Ff(O)454 394 y Fe(sr)q(c)516 387 y Fp(in)o(tends)g(to)g(send)i(a)e
(datagram)f(to)h Ff(H)1148 394 y Fe(dst)1209 387 y Fp(in)g
Ff(O)1293 394 y Fe(dst)1342 387 y Fp(.)19 b(Before)11 b(sending)h(the)g
(datagram,)0 444 y Ff(H)38 451 y Fe(sr)q(c)106 444 y Fp(m)o(ust)17
b(obtain)g(a)g(\\visa-pair",)f(consisting)g(of)h(an)h(exit)f(visa)f(for)h
Ff(O)1277 451 y Fe(sr)q(c)1345 444 y Fp(and)h(an)f(en)o(trance)h(visa)f(for)f
Ff(O)1888 451 y Fe(dst)1937 444 y Fp(.)0 500 y(It)h(do)q(es)f(so)g(b)o(y)h
(con)o(tacting)e Ff(AC)s(S)595 507 y Fe(sr)q(c)646 500 y Fp(,)i(pro)o(ving)e
(its)h(iden)o(tit)o(y)l(,)f(and)i(asking)e(for)h(the)h(appropriate)e
(visa-pair.)23 b(If)0 557 y(comm)o(unication)14 b(is)h(authorized,)g
Ff(AC)s(S)698 564 y Fe(sr)q(c)765 557 y Fp(negotiates)f(with)h
Ff(AC)s(S)1181 564 y Fe(dst)1246 557 y Fp(to)g(obtain)g(an)g(en)o(trance)h
(visa)f(for)f Ff(O)1888 564 y Fe(dst)1937 557 y Fp(,)0 613
y(issues)h(the)g(exit)g(visa)f(for)h Ff(O)492 620 y Fe(sr)q(c)542
613 y Fp(,)g(and)g(returns)g(the)h(visa-pair)e(to)g Ff(H)1173
620 y Fe(sr)q(c)1224 613 y Fp(.)71 709 y(When)j Ff(H)243 716
y Fe(sr)q(c)309 709 y Fp(sends)h(a)e(datagram)f(to)h Ff(H)773
716 y Fe(dst)822 709 y Fp(,)h(it)e(\014rst)i(attac)o(hes)e(the)i(visa)f(to)g
(the)g(datagram)f(\(in)i(a)f(manner)0 765 y(to)d(b)q(e)i(describ)q(ed)g
(shortly\))d(in)i(suc)o(h)g(a)f(w)o(a)o(y)g(that)g(the)h(visa-gatew)o(a)o(ys)
e(can)i(v)o(erify)f(that)g(the)h(comm)o(unication)e(is)0 822
y(authorized.)19 b(This)11 b(v)o(eri\014cation)g(is)h(done)g
Fi(solely)f Fp(b)o(y)i(applying)e(cryptographic)g(mec)o(hanisms)h(to)g(the)g
(datagram;)0 878 y(the)j(gatew)o(a)o(ys)f(need)i(not)f(main)o(tain)e(an)o(y)i
(databases.)71 974 y(A)d(gatew)o(a)o(y)g(can)h(v)o(erify)f(that)g(a)g(visa)h
(attac)o(hed)f(to)g(a)h(datagram)e(is)h(v)m(alid)h(b)q(ecause)h(the)f(visa)f
(itself)g(is)g(signed)0 1030 y(b)o(y)h(the)g(issuing)g(A)o(CS.)g(Signature)f
(is)h(accomplished)g(b)o(y)g(encrypting)g(the)h(visa)e(with)h(a)g(k)o(ey)g
(kno)o(wn)g(only)f(to)h(the)0 1087 y(A)o(CSs)f(and)f(gatew)o(a)o(ys)f(of)i
(an)f(organization;)g(this)g(is)g(kno)o(wn)h(as)f(the)h(\\organization)e(k)o
(ey".)18 b(If)12 b(the)g(cryptosystem)0 1143 y(is)j(secure,)g(there)g(is)g
(no)g(c)o(hance)h(of)f(forgery)l(.)71 1239 y(It)c(is)g(harder)g(to)g(see)h
(ho)o(w)f(to)g(protect)g(against)f(a)h(malicious)f(host)h(that)g(obtains)f(a)
i(v)m(alid)f(visa)f(b)o(y)i(monitoring)0 1295 y(the)j(net)o(w)o(ork)f(and)h
(attac)o(hes)f(this)h(visa)f(to)g(its)g(o)o(wn)h(datagrams.)j(The)d(tric)o(k)
f(is)h(to)f(ha)o(v)o(e)h(the)g(source)g(host)f(sign)0 1352
y(ev)o(ery)19 b(datagram)e(using)i(a)f(secret)h(session)f(k)o(ey)h(kno)o(wn)g
(only)f(to)g(the)h(source)g(host)f(and)h(the)g(visa-gatew)o(a)o(ys)0
1408 y(\(and)j(to)f(the)h(A)o(CSs)g(trusted)g(b)o(y)g(those)f(gatew)o(a)o
(ys\).)39 b(This)21 b(k)o(ey)h(is)g(em)o(b)q(edded)h(in)f(the)g(visa)f(attac)
o(hed)h(to)0 1465 y(the)g(datagram,)f(but)h(b)q(ecause)h(the)f(visa)f(is)g
(encrypted)i(with)e(the)h(organization)d(k)o(ey)l(,)24 b(the)d(session)h(k)o
(ey)f(is)0 1521 y(not)f(a)o(v)m(ailable)g(to)g(in)o(terlop)q(ers.)35
b(It)21 b(is)f(a)o(v)m(ailable)g(to)g(the)g(visa-gatew)o(a)o(y)f(as)h(a)g
(side-e\013ect)h(of)f(v)o(erifying)g(the)0 1577 y(authen)o(ticit)o(y)f(of)i
(the)g(visa.)36 b(Because)21 b(this)f(k)o(ey)h(b)q(ecomes)h(kno)o(wn)e(to)g
Ff(AC)s(S)1383 1584 y Fe(dst)1454 1577 y Fp(and)h Ff(GW)1627
1584 y Fe(entr)1696 1577 y Fp(,)h(whic)o(h)f(ma)o(y)0 1634
y(not)c(b)q(e)h(en)o(tirely)e(trust)o(w)o(orth)o(y)g(to)g Ff(H)659
1641 y Fe(sr)q(c)710 1634 y Fp(,)h(a)g(new)h(signature)e(k)o(ey)h(should)h(b)
q(e)g(generated)f(for)g(eac)o(h)g(path,)h(and)0 1690 y(di\013eren)o(t)13
b(k)o(eys)h(should)g(b)q(e)g(used)h(for)e(exit)h(and)g(en)o(trance)g(visas.)k
(In)d(this)e(proto)q(col,)g(the)h(function)g(FSIG\()p Fi(data)p
Fp(\))0 1747 y(returns)k(a)h(signature)f(of)g(the)g(data)g(\(for)g(example,)h
(a)f(DES-based)h(Message)f(Authen)o(tication)g(Co)q(de\))g(using)0
1803 y(the)d(secret)g(session)g(k)o(ey)l(,)g(K.)0 1964 y Fr(4.2)56
b(Creation)18 b(of)h(visas)0 2089 y Ff(H)38 2096 y Fe(sr)q(c)98
2089 y Fp(b)q(egins)11 b(the)f(pro)q(cess)g(of)g(visa)g(creation)f(b)o(y)h
(generating)f(t)o(w)o(o)g(signature)g(k)o(eys,)i Ff(K)s(S)s(I)t(G)p
Fp(1)1577 2096 y Fe(H)1606 2100 y Fb(sr)q(c)1662 2089 y Fp(and)g
Ff(K)s(S)s(I)t(G)p Fp(2)1902 2096 y Fe(H)1931 2100 y Fb(sr)q(c)1977
2089 y Fp(.)0 2146 y(It)17 b(then)g(con)o(tacts)g Ff(AC)s(S)434
2153 y Fe(sr)q(c)485 2146 y Fp(,)g(pro)o(v)o(es)f(its)h(iden)o(tit)o(y)877
2129 y Fq(10)913 2146 y Fp(,)g(passes)g(the)g(signature)f(k)o(eys)h(to)f
Ff(AC)s(S)1617 2153 y Fe(sr)q(c)1669 2146 y Fp(,)h(and)g(requests)0
2202 y(a)j(visa-pair)f(for)h(use)h(with)f Ff(H)540 2209 y Fe(dst)589
2202 y Fp(.)35 b(If)21 b(comm)o(unication)e(is)h(authorized,)h
Ff(AC)s(S)1402 2209 y Fe(sr)q(c)1474 2202 y Fp(negotiates)e(with)h
Ff(AC)s(S)1900 2209 y Fe(dst)0 2258 y Fp(\(passing)15 b Ff(K)s(S)s(I)t(G)p
Fp(2)334 2265 y Fe(H)363 2269 y Fb(sr)q(c)409 2258 y Fp(\))g(to)g(obtain)g
(an)g(en)o(trance)h(visa)f(for)g Ff(O)1085 2265 y Fe(dst)1134
2258 y Fp(,)g(issues)g(an)h(exit)f(visa)g(for)g Ff(O)1641 2265
y Fe(sr)q(c)1691 2258 y Fp(,)g(and)h(returns)0 2315 y(the)f(visa-pair)f(to)h
Ff(H)358 2322 y Fe(sr)q(c)408 2315 y Fp(.)71 2410 y(The)g(exit)g(visa)f
(issued)h(b)o(y)h Ff(AC)s(S)641 2417 y Fe(sr)q(c)707 2410 y
Fp(is)375 2523 y Ff(V)402 2530 y Fe(exit)477 2523 y Fp(=)d
Fg(f)p Ff(H)586 2530 y Fe(sr)q(c)636 2523 y Ff(;)8 b(H)695
2530 y Fe(dst)744 2523 y Ff(;)g(K)s(S)s(I)t(G)p Fp(1)921 2530
y Fe(H)950 2534 y Fb(sr)q(c)995 2523 y Ff(;)g(E)s(X)t(P)e(I)t(RAT)g(I)t(O)q
(N)t Fg(g)1380 2505 y Fe(K)r(P)f(RI)s(V)1505 2511 y Fb(O)1528
2515 y(sr)q(c)p 0 2565 780 2 v 37 2592 a Fl(10)69 2608 y Fk(Authen)o
(tication)23 b(metho)q(ds)f(for)g(b)q(oth)h(single-k)o(ey)f(and)h(public-k)o
(ey)f(cryptosystems)h(are)f(describ)q(ed)h(b)o(y)g(Needham)f(and)0
2654 y(Sc)o(hro)q(eder[)p Fd(?)p Fk(,)13 b Fd(?)p Fk(].)952
2828 y Fp(13)p eop
%%Page: 14 14
bop 0 45 a Fp(where)16 b Ff(K)s(P)6 b(RI)t(V)295 52 y Fe(O)322
56 y Fb(sr)q(c)386 45 y Fp(is)15 b(the)i(organization)d(k)o(ey)i(for)g
Ff(O)962 52 y Fe(sr)q(c)1012 45 y Fp(,)g(and)g(EXPIRA)l(TION)i(is)e(a)g
(timestamp)f(indicating)0 102 y(when)h(the)h(visa)e(expires;)h(this)f(allo)o
(ws)f(an)i(A)o(CS)g(to)f(limit)g(the)h(lifetime)e(of)i(the)g(visas)f(it)g
(issues,)h(since)g(\(in)g(this)0 158 y(proto)q(col\))d(explicit)g(visa)g(rev)
o(o)q(cation)g(is)h(exp)q(ensiv)o(e)g(\(see)g(section)g Fh(??)p
Fp(\).)k(An)o(y)c(gatew)o(a)o(y)f(b)q(elonging)g(to)h Ff(O)1818
165 y Fe(sr)q(c)1882 158 y Fp(can)0 214 y(v)o(erify)f(that)f(the)i(visa)f(w)o
(as)f(actually)g(issued)i(b)o(y)f Ff(O)874 221 y Fe(sr)q(c)938
214 y Fp(b)o(y)g(computing)g Fg(f)p Ff(V)d(exit)p Fg(g)1384
198 y Fe(K)r(P)5 b(RI)s(V)1509 204 y Fb(O)1532 208 y(sr)q(c)1595
214 y Fp(and)13 b(v)o(erifying)g(that)0 271 y Ff(K)s(S)s(I)t(G)p
Fp(1)156 278 y Fe(H)185 282 y Fb(sr)q(c)246 271 y Fp(pro)q(duces)j(the)g
(data)e(signature)h(for)f(this)h(datagram.)71 367 y(The)g(en)o(trance)g(visa)
g(issued)g(b)o(y)g Ff(AC)s(S)734 374 y Fe(dst)799 367 y Fp(is)g(similar)372
469 y Ff(V)399 476 y Fe(entr)481 469 y Fp(=)e Fg(f)p Ff(H)590
476 y Fe(sr)q(c)640 469 y Ff(;)8 b(H)699 476 y Fe(dst)747 469
y Ff(;)g(K)s(S)s(I)t(G)p Fp(2)924 476 y Fe(H)953 480 y Fb(sr)q(c)999
469 y Ff(;)g(E)s(X)t(P)e(I)t(RAT)g(I)t(O)q(N)q Fg(g)1381 449
y Fe(K)r(P)f(RI)s(V)1506 455 y Fb(O)1529 464 y(dst)0 571 y
Fp(and)15 b(lik)o(ewise)f(can)i(b)q(e)g(v)o(eri\014ed)f(b)o(y)g(an)o(y)g
(gatew)o(a)o(y)e(b)q(elonging)i(to)g Ff(O)1181 578 y Fe(dst)1230
571 y Fp(.)71 666 y(Note)g(that)g(b)q(ecause)h(the)g(visas)e(are)i(signed)f
(using)g(a)h(single-k)o(ey)f(system,)f Ff(K)s(S)s(I)t(G)p Fp(1)1539
673 y Fe(H)1568 677 y Fb(sr)q(c)1630 666 y Fp(and)i Ff(K)s(S)s(I)t(G)p
Fp(2)1875 673 y Fe(H)1904 677 y Fb(sr)q(c)0 723 y Fp(are)f(k)o(ept)g(secret.)
71 818 y(Once)g(it)f(has)h(a)f(visa-pair,)g Ff(H)586 825 y
Fe(sr)q(c)651 818 y Fp(can)h(send)g(datagrams.)j(Assume)d(that)f(the)h
(datagram)e(that)h(it)g(wishes)h(to)0 875 y(send)h(is)635 931
y Ff(D)q(GRAM)h Fp(=)c Fg(f)p Ff(H)t(E)s(AD)q(E)s(R;)8 b(DAT)e(A)p
Fg(g)0 1015 y Fp(and)15 b(that)g(the)g(header)h(is)477 1117
y Ff(H)t(E)s(AD)q(E)s(R)10 b Fp(=)j Fg(f)p Ff(H)820 1124 y
Fe(sr)q(c)871 1117 y Ff(;)8 b(H)930 1124 y Fe(dst)978 1117
y Ff(;)g(S)s(E)s(QN)d(U)g(M)r(;)j Fi(other\014elds)p Fg(g)0
1219 y Fp(where)14 b(SEQNUM)g(is)g(an)f(ID)h(that)f(is)h(unique)g(to)f(this)g
(datagram)g(\(these)g(IDs)h(can)g(b)q(e)h(recycled)f(after)f(a)h(p)q(erio)q
(d)0 1275 y(at)h(least)f(as)h(long)f(as)h(the)g(expiration)f(time)h(of)g(a)f
(visa\).)71 1371 y Ff(H)109 1378 y Fe(sr)q(c)174 1371 y Fp(m)o(ust)h(create)g
(a)g(\\safe")f(v)o(ersion)g(of)h(the)g(datagram)f(as)h(follo)o(ws:)683
1473 y Ff(D)q(S)s(I)t(G)813 1480 y Fe(exit)887 1473 y Fp(=)e
Ff(F)6 b(S)s(I)t(G)p Fp(\()p Fg(f)p Ff(H)t(E)s(AD)q(E)s(R)o(;)i(DAT)e(A)p
Fg(g)p Ff(;)h(K)s(S)s(I)s(G)p Fp(1)1683 1480 y Fe(H)1712 1484
y Fb(s)o(r)q(c)1757 1473 y Fp(\))676 1542 y Ff(D)q(S)s(I)t(G)806
1549 y Fe(entr)887 1542 y Fp(=)13 b Ff(F)6 b(S)s(I)t(G)p Fp(\()p
Fg(f)p Ff(H)t(E)s(AD)q(E)s(R)o(;)i(DAT)e(A)p Fg(g)p Ff(;)h(K)s(S)s(I)s(G)p
Fp(2)1683 1549 y Fe(H)1712 1553 y Fb(s)o(r)q(c)1757 1542 y
Fp(\))93 1611 y Ff(S)s(AF)f(E)s(H)t(D)q(R)11 b Fp(=)i Fg(f)p
Ff(H)466 1618 y Fe(sr)q(c)516 1611 y Ff(;)8 b(H)575 1618 y
Fe(dst)623 1611 y Ff(;)g(S)s(E)s(QN)d(U)g(M)r(;)j(V)920 1618
y Fe(exit)980 1611 y Ff(;)g(V)1028 1618 y Fe(entr)1096 1611
y Ff(;)g(D)q(S)s(I)t(G)1247 1618 y Fe(exit)1308 1611 y Ff(;)g(D)q(S)s(I)t(G)
1459 1618 y Fe(entr)1526 1611 y Ff(;)g Fi(other\014elds)s Fg(g)928
1680 y Ff(S)s(AF)e(E)s(D)q(GRAM)16 b Fp(=)d Fg(f)p Ff(S)s(AF)6
b(E)s(H)t(D)q(R;)i(D)q(AT)e(A)p Fg(g)71 1821 y Ff(D)q(S)s(I)t(G)201
1828 y Fe(exit)282 1821 y Fp(and)20 b Ff(D)q(S)s(I)t(G)505
1828 y Fe(entr)592 1821 y Fp(are)g(the)g(data)f(signatures.)32
b(They)20 b(are)f(constructed)h(so)f(that)g(all)g(\014elds)g(of)0
1878 y(the)c(original)e(datagram)g(whose)i(v)m(alues)g(m)o(ust)f(b)q(e)h(c)o
(hec)o(k)o(ed)g(are)g(signed)g(b)o(y)f Ff(H)1369 1885 y Fe(sr)q(c)1420
1861 y Fq(11)1457 1878 y Fp(.)20 b(The)15 b(safe)f(datagram)g(still)0
1934 y(includes)f(the)f(con)o(ten)o(ts)g(of)g(the)h(original)d(datagram)h
(header)i(in)f(the)g(unencrypted)i(form,)e(so)g(it)g(can)g(b)q(e)h(handled)0
1990 y(b)o(y)k(non-visa)f(gatew)o(a)o(ys)f(without)h(additional)f(mec)o
(hanism.)24 b(The)18 b(new)f(\014elds)g(in)f(the)h(header)g(are)g(purely)g
(for)0 2047 y(the)e(b)q(ene\014t)i(of)d(visa-gatew)o(a)o(ys.)0
2208 y Fr(4.3)56 b(V)-5 b(eri\014cation)18 b(of)h(visas)0 2333
y Fp(Once)e(the)f(safe)g(datagram)e(has)i(b)q(een)h(constructed,)f(it)f(is)g
(sen)o(t)h(along)f(whatev)o(er)g(route)h(has)g(b)q(een)h(c)o(hosen)f(b)o(y)0
2389 y(the)j(usual)g(means,)g(and)g(ev)o(en)o(tually)f(reac)o(hes)h
Ff(GW)915 2396 y Fe(exit)977 2389 y Fp(.)31 b Ff(GW)1100 2396
y Fe(exit)1182 2389 y Fp(m)o(ust)18 b(v)o(erify)g(that)g(\(1\))g
Ff(V)1634 2396 y Fe(exit)1715 2389 y Fp(is)h(v)m(alid,)g(\(2\))0
2446 y Ff(V)27 2453 y Fe(exit)106 2446 y Fp(allo)o(ws)c Ff(H)281
2453 y Fe(sr)q(c)347 2446 y Fp(to)h(send)h(datagrams)e(to)h
Ff(H)828 2453 y Fe(dst)877 2446 y Fp(,)g(and)h(\(3\))e(the)i(con)o(ten)o(ts)f
(of)g(the)g(datagram)f(are)h(those)h(that)0 2502 y(w)o(ere)e(sen)o(t)g(b)o(y)
g Ff(H)301 2509 y Fe(sr)q(c)351 2502 y Fp(.)20 b(The)c(\014rst)e(condition)h
(is)g(c)o(hec)o(k)o(ed)g(b)o(y)g(computing)339 2604 y Fg(f)p
Ff(H)400 2611 y Fe(sr)q(c)450 2604 y Ff(;)8 b(H)509 2611 y
Fe(dst)558 2604 y Ff(;)g(K)s(S)s(I)t(G)p Fp(1)735 2611 y Fe(H)764
2615 y Fb(sr)q(c)809 2604 y Ff(;)g(E)s(X)t(P)e(I)t(RAT)g(I)t(O)q(N)t
Fg(g)k Fp(=)j Fg(f)p Ff(V)c(exit)p Fg(g)1413 2585 y Fe(K)r(P)c(RI)s(V)1538
2591 y Fb(O)1561 2595 y(sr)q(c)p 0 2646 780 2 v 37 2673 a Fl(11)69
2689 y Fk(It)13 b(ma)o(y)g(b)q(e)g(necessary)h(to)f(include)h(copies)f(of)g
(other)g(header)h(\014elds)f(in)g(the)g(data)g(signatures;)h(see)f(section)g
Fd(??)p Fk(.)952 2828 y Fp(14)p eop
%%Page: 15 15
bop 0 45 a Fp(and)19 b(v)o(erifying)f(that)g(the)h(EXPIRA)l(TION)i(time)d(is)
g(reasonable)h(and)g(has)f(not)h(passed;)i(also,)d(if)g(the)h(visa)f(is)0
102 y(not)h(v)m(alid)f(then)i(the)f(extracted)g Ff(K)s(S)s(I)t(G)p
Fp(1)749 109 y Fe(H)778 113 y Fb(sr)q(c)843 102 y Fp(will)e(b)q(e)j
(meaningless)e(and)i(consequen)o(tly)f(will)e(not)i(pro)q(duce)0
158 y Ff(D)q(S)s(I)t(G)130 165 y Fe(exit)192 158 y Fp(.)g(The)14
b(second)h(condition)e(is)g(c)o(hec)o(k)o(ed)h(b)o(y)g(v)o(erifying)f(that)g
(the)h Ff(H)1329 165 y Fe(sr)q(c)1393 158 y Fp(and)g Ff(H)1518
165 y Fe(dst)1581 158 y Fp(extracted)g(from)f(the)0 214 y(visa)h(are)g(those)
g(found)h(in)g(the)f(datagram)f(header.)21 b(The)14 b(third)g(condition)g(is)
g(c)o(hec)o(k)o(ed)h(b)o(y)g(reconstructing)f(the)0 271 y(original)f(HEADER)j
(and)f(using)g(the)g Ff(K)s(S)s(I)t(G)p Fp(1)819 278 y Fe(H)848
282 y Fb(sr)q(c)910 271 y Fp(extracted)g(from)f(the)h(visa)g(to)f(c)o(hec)o
(k)i(that)429 373 y Ff(F)6 b(S)s(I)t(G)p Fp(\()p Fg(f)p Ff(H)t(E)s(AD)q(E)s
(R)o(;)i(DAT)e(A)p Fg(g)p Ff(;)i(K)r(S)s(I)t(G)o Fp(1)1177
380 y Fe(H)1206 384 y Fb(sr)q(c)1251 373 y Fp(\))k(=)h Ff(D)q(S)s(I)t(G)1459
380 y Fe(exit)0 475 y Fp(If)k(all)g(three)g(conditions)f(are)h(met,)g(then)h
(the)f(datagram)f(is)g(what)h(it)f(purp)q(orts)i(to)e(b)q(e,)i(and)f
(SAFEDGRAM)0 532 y(ma)o(y)d(b)q(e)i(forw)o(arded)f(out)g(of)f(the)i
(organization.)71 627 y(Ev)o(en)o(tually)i(the)h(datagram)f(reac)o(hes)h
Ff(GW)835 634 y Fe(entr)904 627 y Fp(,)h(whic)o(h)g(m)o(ust)e(v)o(erify)h
(that)g Ff(V)1449 634 y Fe(entr)1537 627 y Fp(is)g(v)m(alid,)g
Ff(V)1741 634 y Fe(entr)1830 627 y Fp(allo)o(ws)0 684 y Ff(H)38
691 y Fe(sr)q(c)101 684 y Fp(to)12 b(send)h(datagrams)f(to)g
Ff(H)567 691 y Fe(dst)616 684 y Fp(,)g(and)h(the)g(con)o(ten)o(ts)f(of)h(the)
f(datagram)g(are)g(those)g(that)g(w)o(ere)h(sen)o(t)f(b)o(y)h
Ff(H)1887 691 y Fe(sr)q(c)1937 684 y Fp(.)0 740 y(These)i(conditions)g(are)f
(c)o(hec)o(k)o(ed)i(in)f(the)g(same)g(w)o(a)o(y)f(as)g(they)i(w)o(ere)e(c)o
(hec)o(k)o(ed)i(for)e(the)i(exit)e(visa.)19 b(If)c(they)h(hold,)0
797 y(the)f(datagram)f(can)h(b)q(e)h(deliv)o(ered)f(to)g Ff(H)714
804 y Fe(dst)763 797 y Fp(.)0 957 y Fr(4.4)56 b(Av)n(oiding)18
b(the)g(cost)h(of)g(visa)f(decryption)0 1082 y Fp(Because)f
Ff(V)202 1089 y Fe(entr)288 1082 y Fp(and)g Ff(V)405 1089 y
Fe(exit)484 1082 y Fp(are)g(constan)o(t)e(for)h(as)h(long)f(as)g(they)h(do)g
(not)f(expire,)h(a)f(gatew)o(a)o(y)f(can)i(cac)o(he)g(b)q(oth)0
1139 y(encrypted)f(and)f(decrypted)h(v)m(alues)f(of)f(the)h(visas)g(it)f
(uses.)20 b(When)15 b(a)g(datagram)e(arriv)o(es,)h(a)g(gatew)o(a)o(y)g(uses)h
(the)0 1195 y(encrypted)f(visa)e(found)i(in)f(the)g(datagram)f(as)h(a)g(k)o
(ey)g(to)f(\014nd)i(a)f(cac)o(he)g(en)o(try)l(.)19 b(If)14
b(an)f(en)o(try)g(exists,)f(the)i(gatew)o(a)o(y)0 1252 y(can)h(use)h(the)g
(con)o(ten)o(ts)e(of)h(the)h(decrypted)g(visa,)e(instead)h(of)g(pa)o(ying)f
(the)i(cost)f(of)g(visa)f(decryption)i(\(the)f(data)0 1308
y(signature)f(m)o(ust)h(still)f(b)q(e)h(c)o(hec)o(k)o(ed\).)71
1404 y(The)e(size)g(of)f(the)i(cac)o(he,)f(unlik)o(e)g(the)g(size)g(of)f(the)
i(visa-tables)d(used)j(in)f(the)g(stateful)f(proto)q(col,)g(is)h(relativ)o
(ely)0 1460 y(unimp)q(ortan)o(t.)31 b(In)20 b(the)f(ev)o(en)o(t)g(of)f(cac)o
(he)i(misses)e(only)h(one)g(additional)f(encryption)h(step)g(p)q(er)h
(datagram)d(is)0 1517 y(required,)d(instead)f(of)g(a)h(\015urry)g(of)f
(message)g(exc)o(hanges)976 1500 y Fq(12)1014 1517 y Fp(.)19
b(If)14 b(a)g(gatew)o(a)o(y)e(crashes)h(and)h(reb)q(o)q(ots,)g(it)f(need)h
(only)0 1573 y(retriev)o(e)h(its)h(organization's)e(k)o(ey)i(b)q(efore)g(con)
o(tin)o(uing)g(to)f(pro)q(cess)i(datagrams;)d(no)j(other)e(messages)h(need)h
(b)q(e)0 1630 y(exc)o(hanged.)0 1790 y Fr(4.5)56 b(Rev)n(o)r(cation)0
1915 y Fp(In)15 b(some)e(cases)h(it)g(migh)o(t)f(b)q(e)h(necessary)h(to)e
(rev)o(ok)o(e)g(a)h(visa.)19 b(The)14 b(primary)f(mec)o(hanism)h(for)f(rev)o
(o)q(cation)g(is)h(the)0 1972 y(expiration)h(time)g(con)o(tained)h(in)g(the)g
(visa's)f(cleartext.)22 b(If)16 b(visas)f(are)h(issued)g(with)g(relativ)o
(ely)e(short)h(lifetimes)0 2028 y(\(on)h(the)g(order)g(of)f(min)o(utes)h(or)f
(hours\))h(then)g(it)g(is)f(unlik)o(ely)h(that)f(they)h(will)f(need)i(to)e(b)
q(e)i(explicitly)e(rev)o(ok)o(ed.)0 2085 y(In)h(the)f(stateful)f(proto)q
(col,)g(visas)g(ma)o(y)g(b)q(e)i(rev)o(ok)o(ed)f(explicitly)l(.)j(In)e(the)f
(stateless)f(proto)q(col,)g(if)h(an)g(A)o(CS)g(m)o(ust)0 2141
y(rev)o(ok)o(e)g(an)g(unexpired)i(visa,)d(it)h(needs)i(to)d(c)o(ho)q(ose)i(a)
f(new)h(organization)e(k)o(ey)h(and)h(distribute)f(that)g(k)o(ey)g(to)g(all)0
2198 y(b)q(oundary)f(gatew)o(a)o(ys)d(and)i(A)o(CSs)g(of)f(its)h
(organization.)k(Unfortunately)l(,)12 b(this)h(in)o(v)m(alidates)f(all)g
(visas)g(issued)h(b)o(y)0 2254 y(that)h(organization;)f(b)q(ecause)i(of)g
(this,)f(and)h(b)q(ecause)g(a)g(visa)f(migh)o(t)f(expire)i(b)q(efore)g(a)g
(connection)f(is)h(\014nished,)0 2311 y(all)f(visa)h(users)g(m)o(ust)f(b)q(e)
i(prepared)g(to)f(reapply)g(for)f(new)i(visas)e(at)g(an)o(y)h(p)q(oin)o(t)g
(in)g(a)g(connection.)p 0 2350 780 2 v 37 2377 a Fl(12)69 2393
y Fk(The)c(size)h(of)f(a)g(cac)o(he)h(en)o(try)g(is)f(t)o(wice)f(the)i(size)f
(as)g(in)g(the)h(stateful)f(proto)q(col;)h(this)f(is)g(b)q(ecause)i(b)q(oth)f
(cleartext)f(and)h(ciphertext)0 2439 y(v)o(ersions)i(of)e(visas)i(are)f(cac)o
(hed.)952 2828 y Fp(15)p eop
%%Page: 16 16
bop 0 45 a Fr(4.6)56 b(V)-5 b(ariations)19 b(on)f(the)h(theme)0
170 y Fp(Visas)g(in)h(the)f(stateless)g(proto)q(col)g(ha)o(v)o(e)g(more)g(in)
o(ternal)g(structure)g(than)h(those)f(in)h(the)g(stateful)e(proto)q(col.)0
227 y(Because)e(that)e(structure)h(is)g(visible)g(only)g(to)f(the)h(A)o(CSs)h
(and)f(gatew)o(a)o(ys)e(of)i(their)g(issuing)g(organization,)e(this)0
283 y(allo)o(ws)g(some)i(\015exibilit)o(y)f(in)h(their)g(use.)71
379 y(One)i(p)q(ossibilit)o(y)f(is)g(to)g(use)i(di\013eren)o(t)e
(cryptosystems)g(for)g(visa)h(generation)f(and)h(signature)f(generation.)0
435 y(Since)g(signatures)e(co)o(v)o(er)g(en)o(tire)g(datagrams,)g(they)h(are)
f(b)q(est)i(done)f(with)g(an)f(inexp)q(ensiv)o(e)i(single-k)o(ey)e(system)0
491 y(suc)o(h)e(as)f(DES.)g(On)h(the)f(other)g(hand,)i(visas)d(themselv)o(es)
h(are)g(relativ)o(ely)f(small,)g(and)i(giv)o(en)f(the)g(cac)o(hing)h(sc)o
(heme)0 548 y(describ)q(ed)19 b(in)f(section)f Fh(??)p Fp(,)h(visa)f
(decryption)g(is)h(done)g(infrequen)o(tly)l(.)28 b(Visas)17
b(could)h(therefore)f(b)q(e)i(generated)0 604 y(using)c(a)g(public-k)o(ey)g
(system)g(suc)o(h)g(as)g(RSA.)g(Use)h(of)e(a)h(public-k)o(ey)h
(organizational)c(k)o(ey)j(instead)g(of)g(a)f(single-)0 661
y(k)o(ey)20 b(one)g(w)o(ould)g(reduce)h(the)f(danger)g(of)g(compromising)e
(the)i(secret)g(organizational)e(k)o(ey)l(,)j(since)f(it)g(w)o(ould)0
717 y(nev)o(er)15 b(lea)o(v)o(e)g(the)g(A)o(CS.)71 813 y(It)c(is)h(also)f(p)q
(ossible)g(to)h(include)g(additional)e(datagram-header)h(\014elds)h(in)g(the)
g(visa,)f(thereb)o(y)h(allo)o(wing)e(visas)0 869 y(to)i(b)q(e)h(issued)g(on,)
g(for)f(example,)g(a)h(pro)q(cess-to-pro)q(cess)f(basis)g(rather)h(than)f(a)g
(host-to-host)g(basis.)18 b(Additional)0 926 y(informational)12
b(\014elds)k(for)e(use)h(b)o(y)g(gatew)o(a)o(ys,)e(suc)o(h)i(as)g(a)g(limit)e
(on)i(the)g(pac)o(k)o(et)f(rate)h(or)f(pac)o(k)o(et)h(coun)o(t)g(for)f(the)0
982 y(connection,)19 b(could)g(also)e(b)q(e)j(included)f(in)f(the)h(visa.)29
b(An)o(y)19 b(additional)e(visa)h(\014elds,)h(ho)o(w)o(ev)o(er,)f(increase)h
(the)0 1039 y(pro)q(cessing)c(time)g(in)g(b)q(oth)g(hosts)g(and)g(gatew)o(a)o
(ys,)e(and)i(risk)g(exceeding)h(limits)d(on)i(datagram)f(header)i(size.)0
1219 y Fj(5)69 b(Ev)l(aluation)23 b(and)h(comparison)f(of)g(single-k)n(ey)e
(proto)r(cols)0 1360 y Fp(In)14 b(this)f(section)g(w)o(e)h(ev)m(aluate)f(and)
h(compare)f(the)h(t)o(w)o(o)e(prop)q(osed)i(proto)q(cols)e(on)i(the)g(basis)f
(of)g(their)g(resp)q(ectiv)o(e)0 1416 y(o)o(v)o(erhead)h(costs.)19
b(W)l(e)14 b(separate)g(the)g(costs)g(in)o(to)f(p)q(er-connection)i(costs)f
(and)g(p)q(er-datagram)g(costs)g(for)f(autho-)0 1473 y(rized)k(datagrams.)25
b(P)o(er-connection)18 b(costs)f(include)g(the)h(extra)f(datagrams)f(exc)o
(hanged)i(among)e(visa)h(hosts,)0 1529 y(A)o(CSs,)k(and)f(gatew)o(a)o(ys;)g
(and)g(the)h(storage)d(requiremen)o(ts)i(in)g(gatew)o(a)o(ys)e(and)i(hosts.)
34 b(P)o(er-datagram)19 b(costs)0 1586 y(include)c(encryption)g(and)g
(decryption,)f(additional)g(pac)o(k)o(et)g(length)g(due)i(to)e(the)h(visas,)e
(and)i(table)g(lo)q(okups)f(in)0 1642 y(hosts)h(and)g(gatew)o(a)o(ys.)0
1802 y Fr(5.1)56 b(P)n(er-connection)17 b(costs)0 1926 y Fp(In)f(the)f
(stateful)f(proto)q(col,)g(there)h(are)g(sev)o(eral)g(kinds)g(of)g(p)q
(er-connection)g(costs:)56 2060 y(1.)22 b Fh(Negotiations)i(\(supp)q(orted)h
(b)o(y)f(datagram)h(exc)o(hanges\))g(b)q(et)o(w)o(een)f Ff(H)1544
2067 y Fe(sr)q(c)1619 2060 y Fh(and)h(the)g(A)o(CSs)114 2116
y(in)o(v)o(olv)o(ed)p Fp(:)19 b(A)o(t)d(least)g(2)g(datagrams)f(m)o(ust)h(b)q
(e)i(sen)o(t)e(to)g(request)h(the)f(necessary)h(visas,)f(and)h(at)f(least)f
(2)114 2173 y(datagrams)e(are)i(required)g(to)g(return)g(the)g(visas)g(to)f
Ff(H)1067 2180 y Fe(sr)q(c)1118 2156 y Fq(13)1155 2173 y Fp(.)56
2263 y(2.)22 b Fh(Distribution)c(of)i(visas)f(from)g(A)o(CSs)g(to)h(gatew)o
(a)o(ys)f(\(more)h(datagram)h(exc)o(hanges\))p Fp(:)j(Visas)114
2319 y(m)o(ust)13 b(b)q(e)h(passed)g(to)g(at)f(least)g(t)o(w)o(o)f
(visa-gatew)o(a)o(ys)g(\()p Ff(GW)1108 2326 y Fe(exit)1184
2319 y Fp(and)i Ff(GW)1350 2326 y Fe(entr)1419 2319 y Fp(\);)f(this)h
(requires)f(at)g(least)g(t)o(w)o(o)114 2376 y(datagrams.)18
b(In)e(total,)e Ff(M)h Fp(+)c Ff(N)19 b Fp(suc)o(h)d(datagrams)e(are)h(sen)o
(t)g(if)g(there)g(are)g Ff(M)21 b Fp(p)q(oten)o(tial)14 b(exit)h(gatew)o(a)o
(ys)114 2432 y(and)g Ff(N)20 b Fp(p)q(oten)o(tial)14 b(en)o(trance)h(gatew)o
(a)o(ys.)56 2523 y(3.)22 b Fh(T)l(able)15 b(storage)h(space)f(and)h(main)o
(tenance)g(costs)p Fp(:)j(Storage)12 b(o)o(v)o(erhead,)i(consisting)e(of)h(b)
q(oth)h(space)114 2579 y(and)h(run)o(time)f(costs,)g(is)h(in)o(tro)q(duced)g
(in)g(this)f(proto)q(col)g(mainly)g(b)o(y)h(the)g(need)h(for)f(all)f
(participan)o(ts,)f(but)p 0 2615 780 2 v 37 2642 a Fl(13)69
2658 y Fk(In)e(practice,)h(an)o(y)g(visa)f(proto)q(col)h(ma)o(y)f(require)h
(additional)f(datagrams)h(to)g(b)q(e)f(generated)h(in)f(order)h(for)f
Fa(H)1640 2662 y Fb(sr)q(c)1697 2658 y Fk(to)g(authen)o(ticate)0
2704 y(itself)h(to)h Fa(AC)s(S)222 2708 y Fb(sr)q(c)281 2704
y Fk(and)h Fa(AC)s(S)438 2708 y Fb(dst)482 2704 y Fk(.)952
2828 y Fp(16)p eop
%%Page: 17 17
bop 114 45 a Fp(esp)q(ecially)15 b(gatew)o(a)o(ys,)e(to)h(k)o(eep)i
(visa-tables.)j(Signi\014can)o(t)c(costs)g(are)g(asso)q(ciated)f(with)h(b)q
(oth)g(the)h(space)114 102 y(required)d(to)f(store)h(the)g(table,)f(b)q
(ecause)i(man)o(y)f(connections)g(ma)o(y)f(b)q(e)i(activ)o(e,)e(and)h(the)g
(cost)g(of)g(lo)q(okups,)114 158 y(since)i(one)g(is)g(p)q(erformed)g(for)g
(ev)o(ery)g(datagram)f(forw)o(arded.)71 290 y(In)h(the)h(stateless)e(proto)q
(col,)g(some)g(p)q(er-connection)i(costs)f(are)g(reduced:)56
422 y(1.)22 b Fh(Distribution)i(of)i(visas)f(from)g(A)o(CSs)f(to)j(gatew)o(a)
o(ys)p Fp(:)33 b(This)23 b(is)f(not)g(done)h(at)f(all.)41 b(The)22
b(only)114 478 y(comm)o(unication)10 b(b)q(et)o(w)o(een)j(A)o(CSs)f(and)g
(gatew)o(a)o(ys)f(is)g(the)h(distribution)f(of)h(k)o(eys)g(at)f(infrequen)o
(t)h(in)o(terv)m(als.)56 568 y(2.)22 b Fh(T)l(able)f(storage)h(space)g(and)h
(main)o(tenance)e(costs)p Fp(:)28 b(Since)19 b(the)g(only)g(state)f(stored)h
(in)f(the)i(visa-)114 624 y(gatew)o(a)o(ys)15 b(is)i(the)h(cac)o(he)g(of)f
(decrypted)h(visas,)f(whic)o(h)g(can)h(b)q(e)g(re\014lled)f(at)g(minimal)f
(cost,)h(there)h(is)f(no)114 681 y(need)g(to)f(main)o(tain)f(a)i(complete)f
(table.)24 b(T)l(able)16 b(storage)g(space)h(can)f(b)q(e)i(allo)q(cated)e(to)
g(the)g(exten)o(t)h(that)114 737 y(it)h(is)g(a)o(v)m(ailable.)30
b(Av)o(erage)18 b(p)q(er-datagram)g(costs)g(will)g(increase)h(if)f(the)h(cac)
o(he)g(size)g(is)f(so)h(small)e(as)i(to)114 794 y(signi\014can)o(tly)13
b(reduce)j(hit)f(ratios.)71 925 y(The)i(stateless)g(proto)q(col)f(do)q(es)i
(require)f(eac)o(h)h(A)o(CS)f(to)g(p)q(erform)g(an)g(encryption)h(op)q
(eration)e(to)h(create)g(a)0 982 y(visa.)i(It)14 b(is)g(also)f(more)h(exp)q
(ensiv)o(e,)h(in)f(the)h(stateless)e(proto)q(col,)g(to)h(rev)o(ok)o(e)f(an)i
(unexpired)g(visa)f(b)q(ecause)h(there)0 1038 y(is)g(no)g(w)o(a)o(y)f(to)h
(do)g(this)f(without)h(rev)o(oking)f(all)g(unexpired)i(visas.)71
1134 y(Ov)o(erall,)i(the)h(minim)o(um)f(n)o(um)o(b)q(er)i(of)e(datagrams)g
(required)h(to)f(set)h(up)g(a)g(connection)g(in)g(the)g(stateless)0
1190 y(proto)q(col)13 b(is)h(lo)o(w)o(er)f(at)g(least)g(b)o(y)h(t)o(w)o(o)f
(\(more)h(precisely)l(,)g(b)o(y)g Ff(M)f Fp(+)8 b Ff(N)d Fp(\))14
b(since)g(no)g(visa)f(distribution)g(to)h(gatew)o(a)o(ys)0
1247 y(is)20 b(done.)35 b(In)21 b(addition,)f(the)h(table)f(storage)f(space)h
(and)h(main)o(tenance)f(costs)f(are)h(lo)o(w)o(er)f(for)h(the)g(stateless)0
1303 y(proto)q(col.)0 1462 y Fr(5.2)56 b(P)n(er-datagram)18
b(costs)0 1587 y Fp(The)e(p)q(er-datagram)f(costs)g(for)g(visas)g(are)h(the)f
(additional)g(\014elds)h(in)f(datagrams,)f(table)h(lo)q(ok-ups,)h(and)g
(cryp-)0 1644 y(tographic)e(op)q(erations.)71 1739 y(Eac)o(h)22
b(datagram)f(m)o(ust)h(carry)g(header)h(\014elds)g(for)f(b)q(oth)h(exit)f
(and)h(en)o(trance)g(visas.)41 b(In)23 b(the)g(stateful)0 1796
y(proto)q(col,)c(space)h(is)f(required)g(only)g(for)g(t)o(w)o(o)f(rather)h
(small)f(visas,)i(eac)o(h)f(b)q(eing)h(a)f(data)g(signature.)32
b(In)20 b(the)0 1852 y(stateless)14 b(proto)q(col,)g(space)i(is)f(required)g
(not)g(only)g(for)g(t)o(w)o(o)f(data)h(signatures,)f(but)i(also)e(for)h(t)o
(w)o(o)f(rather)h(large)0 1909 y(visas,)e(eac)o(h)h(con)o(taining)e(\(in)h
(encrypted)i(form\))e(t)o(w)o(o)f(source)i(addresses,)g(a)f(signature)g(k)o
(ey)l(,)h(and)f(an)h(expiration)0 1965 y(time.)71 2061 y(In)f(our)g(implemen)
o(tation)e(using)i(32-bit)f(DES)h(k)o(eys,)g(the)g(visas)f(in)h(the)g
(stateful)f(proto)q(col)g(together)g(require)0 2117 y(8)i(b)o(ytes,)f(while)h
(in)g(the)g(stateless)f(proto)q(col,)f(the)i(t)o(w)o(o)f(visas)g(and)h(data)g
(signatures)f(together)g(require)h(40)f(b)o(ytes)0 2174 y(\(see)i(\014gure)h
Fh(??)p Fp(;)e(note)h(that)g(IP)h(requires)f(an)g(additional)f(4)h(b)o(ytes)g
(to)g(indicate)g(the)g(presence)i(of)e(this)f(option\).)0 2230
y(This)f(di\013erence)h(b)q(et)o(w)o(een)f(the)h(stateful)e(and)i(stateless)e
(proto)q(cols)g(cannot)h(b)q(e)h(ignored,)f(but)h(is)f(b)q(ecoming)g(less)0
2287 y(signi\014can)o(t)h(as)h(net)o(w)o(ork)f(bandwidths)h(increase.)71
2382 y(Both)i(proto)q(cols)g(require)h(essen)o(tially)e(the)i(same)f(n)o(um)o
(b)q(er)i(of)e(table)g(lo)q(okups;)i(the)f(cac)o(he)g(lo)q(okups)g(done)0
2439 y(in)f(the)g(stateless)f(proto)q(col)g(should)h(cost)f(ab)q(out)h(the)g
(same)f(as)h(the)g(table)f(lo)q(okups)h(required)g(in)g(the)g(stateful)0
2495 y(proto)q(col.)22 b(The)16 b(only)g(di\013erence)h(is)e(the)i(size)f(of)
g(the)g(lo)q(okup)g(k)o(ey)l(,)g(whic)o(h)g(is)g(t)o(wice)g(as)f(large)h(in)g
(the)g(stateless)0 2552 y(proto)q(col.)71 2647 y(The)e(cryptographic)f(op)q
(erations)h(required)g(dep)q(end)i(up)q(on)f(the)f(data)g(in)o(tegrit)o(y)e
(sc)o(heme)i(used.)21 b(They)14 b(also)0 2704 y(dep)q(end)i(up)q(on)g
(whether)f(the)g(op)q(eration)f(in)o(v)o(olv)o(es)f(passing)i(o)o(v)o(er)f
(the)h(en)o(tire)f(datagram)f(or)i(o)o(v)o(er)f(only)g(part)g(of)952
2828 y(17)p eop
%%Page: 18 18
bop 0 45 a Fp(the)18 b(datagram.)27 b(F)l(or)18 b(the)g(single-k)o(ey)g(visa)
f(proto)q(cols)g(describ)q(ed)i(in)f(this)g(pap)q(er,)h(the)f(cryptographic)g
(costs)0 102 y(are:)27 b(4)19 b(cryptographic)g(op)q(erations)f(for)g(the)i
(stateful)e(proto)q(col,)g(6)h(op)q(erations)f(for)h(the)g(stateless)f(proto)
q(col)0 158 y(without)12 b(cac)o(he)h(hits,)g(and)g(4)g(op)q(erations)f(for)h
(the)g(stateless)f(proto)q(col)g(with)g(cac)o(he)h(hits)g(\(see)g(table)f
Fh(??)p Fp(\).)19 b(These)0 214 y(v)m(alues)c(include)h(the)f(cryptographic)g
(op)q(erations)f(at)g(the)i(source)f(host)g(and)g(at)g(b)q(oth)g(in)o(terv)o
(ening)f(gatew)o(a)o(ys.)71 310 y(Using)19 b(this)g(analysis)g(w)o(e)h(see)g
(that,)g(giv)o(en)f(a)g(reasonable)h(cac)o(he)g(hit)f(rate)g(for)h(the)g
(stateless)e(proto)q(col,)0 367 y(the)h(p)q(er-datagram)g(encryption)g(costs)
g(are)g(roughly)f(equal)h(for)g(the)g(t)o(w)o(o)f(single-k)o(ey)h(visa)g
(proto)q(cols.)31 b(The)0 423 y(main)20 b(determinan)o(t)f(of)h
(cryptographic)f(cost)h(is)g(the)g(strength)g(of)g(the)g(signature)f
(function,)i(and)g(th)o(us)f(the)0 479 y(vulnerabilit)o(y)14
b(of)g(the)i(system,)e(rather)h(than)g(the)g(particular)f(visa)g(proto)q
(col.)0 640 y Fr(5.3)56 b(Summary)0 765 y Fp(In)22 b(summary)l(,)h(the)f
(stateless)e(visa)h(proto)q(col)g(has)h(lo)o(w)o(er)e(setup)i(costs,)g(p)q
(ossibly)g(lo)o(w)o(er)e(storage)g(costs)i(for)0 822 y(the)c(gatew)o(a)o(ys)d
(\(dep)q(ending)k(up)q(on)f(the)g(cac)o(he)f(size\),)h(but)f(sligh)o(tly)f
(higher)h(p)q(er-datagram)g(pro)q(cessing)h(costs)0 878 y(than)f(the)f
(stateful)g(proto)q(col.)24 b(A)16 b(natural)g(consequence)i(of)e(this)h
(statemen)o(t)e(is)i(that)f(the)g(stateless)g(proto)q(col)0
935 y(pro)o(vides)e(for)g(more)g(e\016cien)o(t)g(handling)g(of)h(brief)f
(connections,)g(since)h(its)e(setup)i(cost)f(is)g(lo)o(w)o(er;)f(in)i
(particular,)0 991 y(the)21 b(critical)e(path)i(is)g(shorter)f(b)o(y)h(one)g
(pac)o(k)o(et-dela)o(y)l(.)36 b(F)l(or)21 b(longer)f(connections,)i(once)f
(the)g(di\013erence)g(in)0 1048 y(setup)14 b(costs)f(has)g(b)q(een)i
(amortized)d(and)i(the)f(gatew)o(a)o(y)f(cac)o(hes)i(are)f(loaded,)g(the)h
(stateless)e(proto)q(col)h(is)g(sligh)o(tly)0 1104 y(less)i(e\016cien)o(t)f
(b)q(ecause)i(it)f(requires)g(longer)f(pac)o(k)o(et)g(headers.)20
b(A)c(c)o(hoice)e(b)q(et)o(w)o(een)i(the)f(stateless)f(and)h(stateful)0
1160 y(proto)q(cols)10 b(ma)o(y)h(dep)q(end)h(on)g(other)e(factors,)h(suc)o
(h)g(as)g(the)h(higher)f(cost)f(of)h(selectiv)o(e)g(rev)o(o)q(cation)f(in)h
(the)g(stateless)0 1217 y(proto)q(col,)j(and)h(the)g(higher)g(cost)g(of)g
(gatew)o(a)o(y)e(table)i(o)o(v)o(er\015o)o(w)f(in)h(the)g(stateful)f(proto)q
(col.)19 b(Alternativ)o(ely)l(,)13 b(one)0 1273 y(could)j(implemen)o(t)f(a)h
(h)o(ybrid)g(proto)q(col)e(that)i(w)o(ould)f(emplo)o(y)g(either)h(the)g
(stateless)f(or)g(the)h(stateful)f(proto)q(col)0 1330 y(dep)q(ending)h(up)q
(on)g(the)g(connection)f(t)o(yp)q(e.)71 1425 y(Either)22 b(proto)q(col)g(dep)
q(ends)j(up)q(on)f(the)f(a)o(v)m(ailabilit)o(y)e(of)h(a)h(high-p)q
(erformance)h(cryptosystem.)43 b(While)0 1482 y(public-k)o(ey)16
b(metho)q(ds)g(do)g(not)f(y)o(et)g(app)q(ear)h(to)f(meet)h(this)f(need)i
(\(the)e(fastest)g(commercially)f(a)o(v)m(ailable)h(hard-)0
1538 y(w)o(are,)f(the)i(Cylink)e(Corp)q(oration)g(CY1024,)g(is)h(sp)q
(eci\014ed)h(to)f(encrypt)g(up)h(to)f(2)g(Kbits/second[)p Fh(?)p
Fp(]\),)f(single-k)o(ey)0 1595 y(systems)21 b(suc)o(h)g(as)g(DES)g(are)f
(already)h(capable)g(of)g(matc)o(hing)f(high-sp)q(eed)i(LAN)g(bandwidths)f
(\(the)g(AMD)0 1651 y(AMZ8068)14 b(is)g(sp)q(eci\014ed)j(to)d(encrypt)i(up)f
(to)g(1.7)f(Mb)o(ytes/second[)p Fh(?)p Fp(]\).)952 2828 y(18)p
eop
%%Page: 19 19
bop 0 45 a Fj(6)69 b(Exp)r(erimen)n(tal)21 b(results)0 186
y Fp(The)16 b(purp)q(ose)g(of)g(our)f(exp)q(erimen)o(ts)h(w)o(as)f(to)g(ev)m
(aluate)h(p)q(er-datagram,)e(connection)i(setup,)g(and)g(o)o(v)o(erall)e
(net-)0 242 y(w)o(ork)h(costs)h(of)g(visa)g(proto)q(cols.)22
b(This)16 b(section)g(presen)o(ts)g(a)g(brief)g(description)g(of)g(our)g
(implemen)o(tation,)f(and)0 299 y(analyzes)h(p)q(erformance)h(measuremen)o
(ts)f(of)h(a)f(protot)o(yp)q(e)g(implemen)o(tation)f(of)h(b)q(oth)h(stateful)
e(and)i(stateless)0 355 y(proto)q(cols.)71 451 y(W)l(e)d(conducted)i(t)o(w)o
(o)d(sets)h(of)g(exp)q(erimen)o(ts,)g(the)h(\014rst)f(on)g(a)g(logical)f(in)o
(ternet)h(in)g(our)h(lab)q(oratory)d(at)i(USC,)0 507 y(and)f(the)g(second)h
(across)e(the)h(D)o(ARP)l(A)g(In)o(ternet.)20 b(The)13 b(lab)q(oratory)e
(data)i(pro)o(vide)f(a)h(basis)f(for)h(comparing)f(the)0 564
y(relativ)o(e)j(o)o(v)o(erheads)h(of)g(the)h(v)m(arious)f(visa)g(proto)q
(cols)f(presen)o(ted.)25 b(The)17 b(In)o(ternet)g(data)e(pro)o(v)o(e)h(the)h
(feasibilit)o(y)0 620 y(of)c(implemen)o(ting)g(visa)g(proto)q(cols)g(in)h(an)
f(op)q(erational)g(in)o(ternet)g(en)o(vironmen)o(t,)g(and)h(illustrate)e(the)
i(relativ)o(ely)0 676 y(lo)o(w)g(o)o(v)o(erhead)h(of)g(visas)f(in)h(a)g(con)o
(text)g(of)f(relativ)o(ely)g(high)h(transmission)e(dela)o(y)l(.)0
837 y Fr(6.1)56 b(Visa)19 b(implemen)n(tation)0 962 y Fp(F)l(or)e(b)q(oth)h
(lab)q(oratory)e(and)h(In)o(ternet)h(exp)q(erimen)o(ts,)g(visa)f(proto)q
(cols)f(w)o(ere)h(implemen)o(ted)h(as)f(mo)q(di\014cations)0
1019 y(to)f(the)h(IP)g(co)q(de)h(in)f(4.3BSD)f(UNIX)h(running)g(on)g(IBM)g
(PC)g(R)l(Ts)1169 1002 y Fq(14)1206 1019 y Fp(.)25 b(Visa-gatew)o(a)o(ys,)15
b(hosts,)h(and)h(A)o(CSs)g(all)0 1075 y(used)j(R)l(Ts)g(with)f(4)g(megab)o
(ytes)g(of)g(in)o(ternal)g(memory)l(.)32 b(The)20 b(R)l(Ts)g(w)o(ere)f
(connected)i(to)e(an)g(Ethernet)h(with)0 1132 y(standard)g(Ungerman-Bass)g
(Ethernet)g(adaptors.)35 b(DES)20 b(encryption,)h(in)f(Electronic)g(Co)q
(de-Bo)q(ok)h(\(ECB\))0 1188 y(mo)q(de,)g(w)o(as)e(done)h(in)g(hardw)o(are)f
(using)h(protot)o(yp)q(e)f(cards)h(from)f(the)h(Information)f(T)l(ec)o
(hnology)g(Cen)o(ter)g(of)0 1245 y(Carnegie-Mellon)e(Univ)o(ersit)o(y)f
(\(CMU-ITC\).)h(Although)h(the)g(AMD)f(AMZ8068)g(c)o(hip)h(used)g(on)g(the)g
(card)g(is)0 1301 y(sp)q(eci\014ed)j(to)e(encrypt)i(up)f(to)g(1.7)f(Mb)o
(ytes/second[)p Fh(?)p Fp(],)g(the)h(protot)o(yp)q(e)f(b)q(oard)h(itself)f
(encrypts)i(large)e(data)0 1357 y(blo)q(c)o(ks)c(at)f(only)h(200)g(Kb)o
(ytes/second)g(due)h(to)f(slo)o(w)f(I/O.)71 1453 y(The)h(IP)h(option)e
(de\014nitions)h(for)f(b)q(oth)i(visa)e(proto)q(cols)g(are)h(depicted)h(in)f
(\014gure)g Fh(??)p Fp(.)71 1549 y(W)l(e)j(encoun)o(tered)i(a)e(signi\014can)
o(t)f(problem)i(with)e(our)i(\014rst)f(implemen)o(tation)f(of)h(the)h
(stateless)e(proto)q(col)0 1605 y({)22 b(w)o(e)f(exceeded)j(the)e(maxim)o(um)
f(IP)h(header)g(size)g(of)g(60)f(b)o(ytes!)40 b(In)23 b(order)e(to)h
(implemen)o(t)f(the)h(stateless)0 1662 y(proto)q(col)16 b(within)g(existing)f
(IP)l(,)i(w)o(e)g(cut)f(do)o(wn)h(the)g(size)f(of)h(DES)f(k)o(eys)h(and)g
(data)f(signatures)f(from)h(64)g(to)h(32)0 1718 y(bits.)k(Although)15
b(clev)o(er)g(enco)q(ding)h(tec)o(hniques)g(could)g(b)q(e)g(used)h(used)f(to)
f(pac)o(k)g(additional)g(k)o(ey)g(bits)g(in)o(to)g(the)0 1775
y(header,)j(the)g(stateless)e(proto)q(col)g(is)h(unlik)o(ely)g(to)g(co)q
(exist)g(with)f(an)o(y)i(other)f(IP)g(options,)g(due)h(to)f(the)h(header)0
1831 y(length)d(limit.)0 1992 y Fr(6.2)56 b(Exp)r(erimen)n(tal)16
b(con\014gurations)0 2117 y Fp(F)l(or)f(the)h(lab)q(oratory)e(exp)q(erimen)o
(ts,)h(w)o(e)g(created)h(logically)e(separate)h(net)o(w)o(orks)f(on)i(top)f
(of)g(a)h(single)f(ph)o(ysical)0 2173 y(net)o(w)o(ork)f(b)o(y)h(manipulating)
f(the)h(routing)g(databases)f(for)h(lo)q(cal)f(hosts)h(\(see)g(\014gure)g
Fh(??)p Fp(\).)71 2269 y(Our)21 b(In)o(ternet)g(con\014guration)f(consisted)g
(of)h(net)o(w)o(orks)e(in)i(t)o(w)o(o)e(univ)o(ersities,)i(USC)g(and)g(UCLA,)
g(eac)o(h)0 2325 y(connected)16 b(to)f(the)g(ARP)l(Anet.)22
b(The)15 b(visa)g(net)o(w)o(orks)f(sit)h(within)f(campus)i(net)o(w)o(orks)e
(whic)o(h)h(eac)o(h)h(connect)g(to)0 2382 y(the)f(ARP)l(Anet)h(\(see)g
(\014gure)f Fh(??)p Fp(\).)p 0 2424 780 2 v 37 2451 a Fl(14)69
2467 y Fk(The)f(IBM)h(PC)f(R)m(T)g(scores)h(2690)g(on)f(the)h(\\Dhrystone)h
(b)q(enc)o(hmark",)g(compared)f(with)f(2993)h(for)f(SUN)g(3/50)h(and)g(1577)g
(for)0 2512 y(Digital)d(Equipmen)o(t)i(Corp)q(oration)g(MicroV)m(ax)f(I)q(I.)
952 2828 y Fp(19)p eop
%%Page: 20 20
bop 240 550 a
 21313290 21313290 0 0 33680261 45323632 startTexFig
240 550 a
%%BeginDocument: options.ps
gsave
/fig2psdict 20 dict def
fig2psdict begin
72     80 div dup scale
        10       820 translate
   -22   -26 translate
/mtrx matrix currentmatrix def
180 rotate
[-1 0 0 1 0 0] concat
/arrowhead
 { /headlength exch def
 /halfheadheight exch 2 div def
 /tipy exch def
 /tipx exch def
 /taily exch def
 /tailx exch def
 /angle tipy taily sub tipx tailx sub atan def
 /savematrix matrix currentmatrix def
 tipx tipy translate
 angle 90 add rotate
 halfheadheight headlength moveto
 0 0 lineto
 halfheadheight neg headlength lineto
 savematrix setmatrix
} def
/printtext 
 { /txt exch def
 /width exch def
 /height exch def
 /y exch def
 /x exch def
 gsave
 /Courier findfont height scalefont setfont
 /Courier findfont 
 [ width txt stringwidth pop div height mul 0 0 height 0 0] makefont
 setfont
 x y moveto
 mtrx setmatrix
 txt show
 grestore
} def

       101       706        16       240 (Exit Data Signature \(DSIGexit\)) printtext
       143       378        16       112 (Source Address) printtext
        42       181        16        32 (8-11) printtext
        43       142        16        24 (4-7) printtext
        43       103        16        24 (0-3) printtext
        43       387        16        24 (4-7) printtext
        43       343        16        24 (0-3) printtext
        42       426        16        32 (8-11) printtext
        33       460        16        40 (12-15) printtext
        33       742        16        40 (40-43) printtext
        33       697        16        40 (36-39) printtext
        34       659        16        40 (32-35) printtext
        34       619        16        40 (28-31) printtext
        33       582        16        40 (24-27) printtext
        33       538        16        40 (20-23) printtext
        32       500        16        40 (16-19) printtext
       573       599        16         8 (:) printtext
       569       440        16         8 (:) printtext
       225       581        16         8 (A) printtext
       530       624        16        40 (Kpriv) printtext
       475       635        16        56 ([Ventr]) printtext
       564       473        16        32 (osrc) printtext
       529       465        16        40 (Kpriv) printtext
       473       475        16        56 ([Vexit]) printtext
       487       582        16        72 (ENCRYPTED) printtext
       493       422        16        72 (ENCRYPTED) printtext
        96       270        16       280 (Visa Option in the Stateless Scheme) printtext
        97        25        16       272 (Visa Option in the Stateful Scheme) printtext
        79        90        16        72 (IP option) printtext
        84       106        16        32 (type) printtext
       161        90        16        72 (IP option) printtext
       163       106        16        48 (length) printtext
       276       102        16        56 (PADDING) printtext
       166       140        16       120 (EXIT VISA STAMP) printtext
       167       179        16       128 (ENTRY VISA STAMP) printtext
        73        72        16         8 (0) printtext
       152        73        16         8 (7) printtext
       227        73        16        16 (15) printtext
       309        74        16        16 (23) printtext
       385        74        16        16 (31) printtext
        73       312        16         8 (0) printtext
       152       313        16         8 (7) printtext
       227       313        16        16 (15) printtext
       309       314        16        16 (23) printtext
       385       314        16        16 (31) printtext
        89       351        16        32 (type) printtext
        79       330        16        72 (IP option) printtext
       161       330        16        72 (IP option) printtext
       163       351        16        48 (length) printtext
       276       342        16        56 (PADDING) printtext
       126       421        16        24 (Des) printtext
       151       421        16        24 (tin) printtext
       176       421        16        24 (ati) printtext
       201       421        16        80 (on Address) printtext
        96       461        16        24 (Dat) printtext
       121       461        16        24 (a S) printtext
       146       461        16        24 (ign) printtext
       171       461        16        24 (atu) printtext
       196       461        16       144 (re Key \(KSIGexit\) ) printtext
       186       501        16        24 (EXP) printtext
       146       541        16        24 (Sou) printtext
       171       541        16        24 (rce) printtext
       204       541        16        24 (Add) printtext
       227       541        16        24 (res) printtext
       251       541        16         8 (s) printtext
       126       581        16        24 (Des) printtext
       151       581        16        24 (tin) printtext
       176       581        16        24 (ati) printtext
       201       581        16        24 (on ) printtext
       233       581        16        24 (ddr) printtext
       257       581        16        24 (ess) printtext
       211       501        16        24 (IRA) printtext
       236       501        16        24 (TIO) printtext
       261       501        16         8 (N) printtext
        96       621        16        24 (Dat) printtext
       121       621        16        24 (a S) printtext
       146       621        16        24 (ign) printtext
       171       621        16        24 (atu) printtext
       196       621        16       144 (re Key \(KSIGentr\) ) printtext
       186       666        16        24 (EXP) printtext
       211       666        16        24 (IRA) printtext
       236       666        16        24 (TIO) printtext
       261       666        16         8 (N) printtext
        96       741        16        24 (Ent) printtext
       121       741        16        24 (ry ) printtext
       146       741        16        24 (Dat) printtext
       171       741        16        24 (a S) printtext
       196       741        16        24 (ign) printtext
       221       741        16        24 (atu) printtext
       246       741        16        24 (re ) printtext
       271       741        16        24 (\(DS) printtext
       296       741        16        24 (IGe) printtext
       321       741        16        24 (ntr) printtext
       346       741        16         8 (\)) printtext
       486       601        16        24 (ENT) printtext
       511       601        16        24 (RY ) printtext
       536       601        16        24 (VIS) printtext
       561       601        16         8 (A) printtext
       491       441        16        24 (EXI) printtext
       516       441        16        24 (T V) printtext
       541       441        16        24 (ISA) printtext
         1 setlinewidth
newpath
        80       675 moveto
       394       675 lineto
stroke
newpath
        76       674 moveto
        79       677 lineto
stroke
newpath
       394       515 moveto
       394       675 lineto
stroke
newpath
        79       518 moveto
        79       678 lineto
stroke
newpath
       394       360 moveto
       394       515 lineto
stroke
newpath
        79       359 moveto
        79       521 lineto
stroke
newpath
        78       359 moveto
        77       412 lineto
stroke
newpath
        78       359 moveto
        78       376 lineto
stroke
newpath
        77       358 moveto
        77       363 lineto
stroke
newpath
        75        78 moveto
       396        78 lineto
       396       197 lineto
        75       197 lineto
        75        78 lineto
stroke
newpath
        80       519 moveto
       396       519 lineto
stroke
newpath
        81       517 moveto
       395       517 lineto
stroke
newpath
        80       518 moveto
        77       516 lineto
stroke
newpath
        79       518 moveto
        77       515 lineto
stroke
newpath
        79       518 moveto
       398       518 lineto
stroke
newpath
        77       677 moveto
       398       677 lineto
stroke
newpath
        76       316 moveto
       397       316 lineto
       397       397 lineto
        76       397 lineto
        76       316 lineto
stroke
newpath
        76       678 moveto
       398       678 lineto
stroke
newpath
        77       676 moveto
       396       676 lineto
       396       676 lineto
        77       676 lineto
        77       676 lineto
stroke
newpath
        77       557 moveto
        77       674 lineto
stroke
newpath
        78       361 moveto
        78       677 lineto
stroke
newpath
       396       360 moveto
       396       677 lineto
stroke
newpath
       395       359 moveto
       395       675 lineto
stroke
newpath
       397       357 moveto
       397       555 lineto
stroke
newpath
        77       359 moveto
        77       557 lineto
stroke
newpath
        76       358 moveto
       398       358 lineto
stroke
newpath
        76       357 moveto
       397       357 lineto
stroke
newpath
        76       359 moveto
       397       359 lineto
stroke
newpath
        76       357 moveto
       395       357 lineto
stroke
newpath
        75       157 moveto
       395       157 lineto
       395       157 lineto
        75       157 lineto
        75       157 lineto
stroke
newpath
        75        78 moveto
       156        78 lineto
       156       116 lineto
        75       116 lineto
        75        78 lineto
stroke
newpath
        76       396 moveto
       397       396 lineto
       397       477 lineto
        76       477 lineto
        76       396 lineto
stroke
newpath
        76       476 moveto
       397       476 lineto
       397       557 lineto
        76       557 lineto
        76       476 lineto
stroke
newpath
        76       556 moveto
       397       556 lineto
       397       637 lineto
        76       637 lineto
        76       556 lineto
stroke
newpath
        76       636 moveto
       397       636 lineto
       397       717 lineto
        76       717 lineto
        76       636 lineto
stroke
newpath
        76       356 moveto
       396       356 lineto
stroke
newpath
       396       436 moveto
        76       436 lineto
stroke
newpath
        76       356 moveto
       396       356 lineto
stroke
newpath
        76       516 moveto
       396       516 lineto
stroke
newpath
        76       596 moveto
       396       596 lineto
stroke
newpath
        76       676 moveto
       396       676 lineto
stroke
newpath
       156       316 moveto
       156       356 lineto
stroke
newpath
       236       316 moveto
       236       356 lineto
stroke
newpath
       236        76 moveto
       236       116 lineto
stroke
newpath
        75       116 moveto
       396       116 lineto
       396       197 lineto
        75       197 lineto
        75       116 lineto
stroke
newpath
       411       356 moveto
394.2692 436.0000 81.7308 -80.0000 16.7308 atan 80.0000 16.7308 atan arc
stroke
newpath
489.3059 499.6235       411       516         4         8 arrowhead
stroke
newpath
489.3059 372.3765       411       356         4         8 arrowhead
stroke
newpath
       411       516 moveto
394.2692 596.0000 81.7308 -80.0000 16.7308 atan 80.0000 16.7308 atan arc
stroke
newpath
489.3059 659.6235       411       676         4         8 arrowhead
stroke
newpath
489.3059 532.3765       411       516         4         8 arrowhead
stroke
       145       774        16       120 (Total: 44 bytes) printtext
       133       214        16       120 (Total: 12 bytes) printtext
newpath
       397       678 moveto
       398       754 lineto
stroke
newpath
        76       718 moveto
       398       718 lineto
       398       756 lineto
        76       756 lineto
        76       718 lineto
stroke
       568       629        16        32 (odst) printtext
showpage
end % fig2psdict
grestore
%%EndDocument
 240 550 a
 endTexFig
640 2148 a Fp(Figure)15 b(2:)k(Visa)c(Option)g(De\014nitions)952
2828 y(20)p eop
%%Page: 21 21
bop 41 1302 a Fp(Figure)15 b(3:)k(Lab)q(oratory)c(con\014guration.)k
(Logically)13 b(separate)i(net)o(w)o(orks)f(on)h(a)g(single)g(ph)o(ysical)f
(net)o(w)o(ork.)31 2669 y(Figure)g(4:)20 b(In)o(ternet)15 b(con\014guration.)
k(Ph)o(ysical)14 b(connections)i(b)q(et)o(w)o(een)f(USC)g(and)h(UCLA)f(visa)g
(net)o(w)o(orks.)952 2828 y(21)p eop
%%Page: 22 22
bop 323 55 1305 2 v 322 112 2 57 v 331 112 V 947 112 V 956
112 V 956 112 V 1064 95 a Fp(Datagram)14 b(Size)h(\(b)o(ytes\))p
1618 112 V 1627 112 V 957 113 671 2 v 322 168 2 57 v 331 168
V 566 151 a(V)l(ersion)p 947 168 V 956 168 V 268 w(16)p 1051
168 V 50 w(64)p 1146 168 V 49 w(250)p 1264 168 V 49 w(500)p
1382 168 V 49 w(750)p 1500 168 V 49 w(900)p 1618 168 V 1627
168 V 323 170 1305 2 v 323 172 V 322 226 2 57 v 331 226 V 356
209 a(Without)f(VISA)p 947 226 V 956 226 V 333 w(10)p 1051
226 V 50 w(11)p 1146 226 V 72 w(21)p 1264 226 V 72 w(32)p 1382
226 V 72 w(42)p 1500 226 V 72 w(49)p 1618 226 V 1627 226 V
323 228 1305 2 v 322 284 2 57 v 331 284 V 356 267 a(Stateful)g(without)g
(encryption)p 947 284 V 956 284 V 75 w(12)p 1051 284 V 50 w(14)p
1146 284 V 72 w(23)p 1264 284 V 72 w(34)p 1382 284 V 72 w(46)p
1500 284 V 72 w(52)p 1618 284 V 1627 284 V 323 286 1305 2 v
322 342 2 57 v 331 342 V 356 325 a(Stateful)p 947 342 V 956
342 V 469 w(19)p 1051 342 V 50 w(23)p 1146 342 V 72 w(40)p
1264 342 V 72 w(61)p 1382 342 V 72 w(83)p 1500 342 V 72 w(95)p
1618 342 V 1627 342 V 323 344 1305 2 v 322 400 2 57 v 331 400
V 356 383 a(Stateless)g(without)g(encryption)p 947 400 V 956
400 V 58 w(14)p 1051 400 V 50 w(16)p 1146 400 V 72 w(25)p 1264
400 V 72 w(36)p 1382 400 V 72 w(48)p 1500 400 V 72 w(54)p 1618
400 V 1627 400 V 323 402 1305 2 v 322 459 2 57 v 331 459 V
356 442 a(Stateless)g(with)h(cac)o(he)g(hits)p 947 459 V 956
459 V 138 w(20)p 1051 459 V 50 w(25)p 1146 459 V 72 w(41)p
1264 459 V 72 w(63)p 1382 459 V 72 w(84)p 1500 459 V 72 w(96)p
1618 459 V 1627 459 V 323 460 1305 2 v 322 517 2 57 v 331 517
V 356 500 a(Stateless)f(with)h(no)g(cac)o(he)g(hits)p 947 517
V 956 517 V 75 w(24)p 1051 517 V 50 w(29)p 1146 517 V 72 w(44)p
1264 517 V 72 w(66)p 1382 517 V 72 w(88)p 1500 517 V 49 w(100)p
1618 517 V 1627 517 V 323 518 1305 2 v 302 596 a(T)l(able)g(1:)k(Round-trip)d
(datagram)e(times)g(for)h(the)g(lab)q(oratory)e(exp)q(erimen)o(t.)375
777 y(Figure)h(5:)20 b(Graphical)14 b(represen)o(tation)g(of)h(the)g(lab)q
(oratory)e(results.)0 910 y Fr(6.3)56 b(Lab)r(oratory)17 b(measuremen)n(ts)0
1035 y Fp(In)11 b(the)g(lab)q(oratory)f(exp)q(erimen)o(t)g(w)o(e)h(measured)g
(the)g(round-trip)g(datagram)e(times)h(for)g(b)q(oth)h(visa)f(and)h(non-visa)
0 1092 y(implemen)o(tations)16 b(under)j(conditions)e(of)h(similar)e(net)o(w)
o(ork)h(load.)27 b(W)l(e)18 b(measured)g(six)g(proto)q(col)f(v)m(ariations:)0
1148 y(no)d(visas,)f(the)g(stateful)g(and)h(stateless)f(visa)g(proto)q(cols)f
(without)h(encryption)h(\(to)e(measure)i(the)g(o)o(v)o(erhead)f(due)0
1205 y(to)k(the)h(additional)f(header)h(length)f(of)h(visa)f(pac)o(k)o
(ets\),)g(the)h(stateful)f(proto)q(col,)g(and)h(the)g(stateless)f(proto)q
(col)0 1261 y(with)e(and)g(without)f(cac)o(he)i(hits.)71 1357
y(After)10 b(the)g(initial)f(connection)h(setup,)i(datagram)d(round-trip)h
(time)g(w)o(as)f(measured)i(using)f(the)h(ICMP)f(Ec)o(ho)0
1413 y(proto)q(col[)p Fh(?)p Fp(].)17 b(In)e(this)f(proto)q(col,)f(a)h
(request)g(datagram)f(tra)o(v)o(els)g(from)g Ff(H)1266 1420
y Fe(sr)q(c)1331 1413 y Fp(to)h(the)g Ff(H)1501 1420 y Fe(dst)1550
1413 y Fp(,)g(whic)o(h)g(immediately)0 1470 y(returns)19 b(a)g(reply)g
(datagram.)30 b(W)l(e)19 b(used)h(ICMP)f(Ec)o(ho)g(instead)f(of)h(an)g
(application)f(proto)q(col)g(\(suc)o(h)h(as)g(\014le)0 1526
y(transfer)g(or)h(remote)f(login\))g(to)g(isolate,)g(as)h(m)o(uc)o(h)g(as)g
(p)q(ossible,)g(the)g(o)o(v)o(erhead)g(asso)q(ciated)f(with)h(the)g(visa)0
1583 y(proto)q(cols.)71 1678 y(T)l(able)f Fh(??)32 b Fp(sho)o(ws)19
b(measured)h(round-trip)f(datagram)f(times)h(for)g(datagrams)f(of)h(v)m
(arying)g(data)g(length.)0 1735 y(The)c(results)f(are)h(also)e(presen)o(ted)j
(in)e(graphical)g(form)g(in)h(\014gure)g Fh(??)p Fp(.)k(The)c(sligh)o(t)e(p)q
(erformance)i(adv)m(an)o(tage)f(of)0 1791 y(the)h(stateful)f(proto)q(col)h
(comes)g(from)f(the)h(shorter)g(header)h(used,)f(compared)g(with)g(the)g
(stateless)f(proto)q(col.)71 1887 y(A)h(signi\014can)o(t)g(p)q(ortion)f(of)i
(the)f(visa)g(proto)q(col)f(o)o(v)o(erhead)i(is)f(due)h(to)f(encryption.)21
b(T)l(able)15 b Fh(??)21 b Fp(summarizes)0 1943 y(the)f(p)q(er-datagram)f
(cryptographic)g(costs)g(for)g(the)h(three)g(v)m(ariations)f(describ)q(ed)h
(in)g(sections)f Fh(??)34 b Fp(and)20 b Fh(??)p Fp(.)0 2000
y(Note)e(that)f(the)i(encryption)f(o)o(v)o(erhead)g(for)f(the)i(stateless)e
(proto)q(col)g(with)h(cac)o(he)g(hits)g(is)g(the)g(same)g(as)g(that)0
2056 y(for)f(the)g(stateful)f(proto)q(col.)25 b(The)17 b(table)g(giv)o(es)g
(one-w)o(a)o(y)f(o)o(v)o(erhead;)h(for)g(the)g(round-trip)g(measuremen)o(ts)g
(w)o(e)0 2113 y(made,)e(t)o(wice)f(as)h(man)o(y)g(encryptions)g(are)g(p)q
(erformed.)71 2208 y(Actual)f(measuremen)o(ts)h(of)g(the)g(total)f
(encryption)h(costs)g(are)f(sho)o(wn)h(in)g(table)g Fh(??)p
Fp(.)71 2304 y(These)i(measuremen)o(ts)g(corresp)q(ond)h(closely)f(to)g
(calculations)f(based)i(up)q(on)g(the)f(n)o(um)o(b)q(er)h(of)f(encryption)0
2360 y(op)q(erations.)41 b(F)l(or)23 b(example,)h(a)e(round-trip)g(for)g(a)h
(1)f(Kb)o(yte)h(datagram)e(requires)i(8)f(encryptions;)k(at)c(an)0
2417 y(encryption)13 b(rate)e(of)i(200)e(Kb)o(ytes/second,)i(encrypting)g(8K)
g(b)o(ytes)f(should)g(tak)o(e)g(40)g(ms.)19 b(The)13 b(measured)g(v)m(alue)0
2473 y(is)j(53)h(ms.)25 b(The)17 b(discrepancy)g(comes)g(from)f(p)q
(er-datagram)g(o)o(v)o(erhead)h(in)f(using)h(the)g(encryption)g(hardw)o(are,)
0 2530 y(whic)o(h)h(is)g(not)h(re\015ected)g(in)f(the)h(nominal)e(200)h(Kb)o
(yte/second)h(rate)f(\(measured)g(for)g(encryptions)h(of)f(m)o(uc)o(h)0
2586 y(larger)c(data)h(blo)q(c)o(ks\).)71 2682 y(Since)20 b(it)f(should)g(b)q
(e)i(p)q(ossible)e(to)g(emplo)o(y)g(the)h(AMZ8068)e(DES)h(c)o(hip)h(to)f
(encrypt)h(data)f(at)g(up)h(to)f(1.7)952 2828 y(22)p eop
%%Page: 23 23
bop 259 368 1433 2 v 258 424 2 57 v 267 424 V 818 424 V 827
424 V 826 424 V 1182 407 a Fp(V)l(ersion)p 1682 424 V 1691
424 V 827 426 865 2 v 258 481 2 57 v 267 481 V 442 464 a(Op)q(eration)p
818 481 V 827 481 V 209 w(Stateful)p 1031 481 V 49 w(Stateless)14
b(with)p 1357 481 V 49 w(Stateless)h(with)p 1682 481 V 1691
481 V 258 537 V 267 537 V 818 537 V 827 537 V 1031 537 V 1065
520 a(no)g(cac)o(he)h(hits)p 1357 537 V 97 w(cac)o(he)g(hits)p
1682 537 V 1691 537 V 259 539 1433 2 v 259 541 V 258 595 2
57 v 267 595 V 292 578 a Ff(H)330 585 y Fe(sr)q(c)395 578 y
Fp(creates)f Ff(V)574 585 y Fe(exit)p 818 595 V 826 595 V 912
578 a Fp(X)p 1031 595 V 1357 595 V 1682 595 V 1691 595 V 259
597 1433 2 v 258 653 2 57 v 267 653 V 292 636 a Ff(H)330 643
y Fe(sr)q(c)395 636 y Fp(creates)g Ff(V)574 643 y Fe(entr)p
818 653 V 826 653 V 912 636 a Fp(X)p 1031 653 V 1357 653 V
1682 653 V 1691 653 V 259 655 1433 2 v 258 712 2 57 v 267 712
V 292 695 a Ff(H)330 702 y Fe(sr)q(c)395 695 y Fp(creates)g
Ff(D)q(S)s(I)t(G)677 702 y Fe(exit)p 818 712 V 826 712 V 1031
712 V 1178 695 a Fp(X)p 1357 712 V 291 w(X)p 1682 712 V 1691
712 V 259 713 1433 2 v 258 770 2 57 v 267 770 V 292 753 a Ff(H)330
760 y Fe(sr)q(c)395 753 y Fp(creates)g Ff(D)q(S)s(I)t(G)677
760 y Fe(entr)p 818 770 V 826 770 V 1031 770 V 1178 753 a Fp(X)p
1357 770 V 291 w(X)p 1682 770 V 1691 770 V 259 771 1433 2 v
258 828 2 57 v 267 828 V 292 811 a Ff(GW)371 818 y Fe(exit)449
811 y Fp(c)o(hec)o(ks)g Ff(V)616 818 y Fe(exit)p 818 828 V
826 828 V 912 811 a Fp(X)p 1031 828 V 232 w(X)p 1357 828 V
1682 828 V 1691 828 V 259 829 1433 2 v 258 886 2 57 v 267 886
V 292 869 a Ff(GW)371 876 y Fe(entr)455 869 y Fp(c)o(hec)o(ks)g
Ff(V)622 876 y Fe(entr)p 818 886 V 826 886 V 912 869 a Fp(X)p
1031 886 V 232 w(X)p 1357 886 V 1682 886 V 1691 886 V 259 888
1433 2 v 258 944 2 57 v 267 944 V 292 927 a Ff(GW)371 934 y
Fe(exit)449 927 y Fp(c)o(hec)o(ks)g Ff(D)q(S)s(I)t(G)719 934
y Fe(exit)p 818 944 V 826 944 V 1031 944 V 1178 927 a Fp(X)p
1357 944 V 291 w(X)p 1682 944 V 1691 944 V 259 946 1433 2 v
258 1002 2 57 v 267 1002 V 292 985 a Ff(GW)371 992 y Fe(entr)455
985 y Fp(c)o(hec)o(ks)g Ff(D)q(S)s(I)t(G)725 992 y Fe(entr)p
818 1002 V 826 1002 V 1031 1002 V 1178 985 a Fp(X)p 1357 1002
V 291 w(X)p 1682 1002 V 1691 1002 V 259 1004 1433 2 v 258 1060
2 57 v 267 1060 V 292 1043 a(TOT)l(AL)h(NUMBER)p 818 1060 V
827 1060 V 245 w(4)p 1031 1060 V 242 w(6)p 1357 1060 V 303
w(4)p 1682 1060 V 1691 1060 V 259 1062 1433 2 v 487 1189 a(T)l(able)f(2:)k(P)
o(er-datagram)14 b(cryptographic)g(op)q(erations.)p 388 1908
1175 2 v 387 1964 2 57 v 396 1964 V 696 1947 a(Ov)o(erhead)i(due)g(to)f
(encryption)p 1553 1964 V 1562 1964 V 388 1966 1175 2 v 388
1968 V 387 2023 2 57 v 396 2023 V 995 2023 V 1004 2023 V 1003
2023 V 1029 2006 a(Datagram)e(Size)j(\(in)e(b)o(ytes\))p 1553
2023 V 1562 2023 V 1004 2024 558 2 v 387 2079 2 57 v 396 2079
V 623 2062 a(V)l(ersion)p 995 2079 V 1004 2079 V 259 w(16)p
1099 2079 V 49 w(64)p 1194 2079 V 50 w(500)p 1312 2079 V 149
w(1000)p 1553 2079 V 1562 2079 V 388 2081 1175 2 v 388 2083
V 387 2137 2 57 v 396 2137 V 421 2120 a(Stateful)p 995 2137
V 1004 2137 V 475 w(8)p 1099 2137 V 49 w(10)p 1194 2137 V 72
w(31)p 1312 2137 V 195 w(53)p 1553 2137 V 1562 2137 V 388 2139
1175 2 v 387 2195 2 57 v 396 2195 V 421 2178 a(Stateless)g(with)h(cac)o(he)g
(hits)p 995 2195 V 1004 2195 V 144 w(8)p 1099 2195 V 49 w(10)p
1194 2195 V 72 w(31)p 1312 2195 V 195 w(53)p 1553 2195 V 1562
2195 V 388 2197 1175 2 v 387 2253 2 57 v 396 2253 V 421 2236
a(Stateless)f(with)h(no)g(cac)o(he)h(hits)p 995 2253 V 1004
2253 V 57 w(13)p 1099 2253 V 49 w(15)p 1194 2253 V 72 w(36)p
1312 2253 V 195 w(58)p 1553 2253 V 1562 2253 V 388 2255 1175
2 v 187 2382 a(T)l(able)f(3:)20 b(P)o(er-datagram)13 b(encryption)j(costs)e
(of)h(stateful)f(and)i(stateless)e(visa)g(proto)q(cols.)952
2828 y(23)p eop
%%Page: 24 24
bop 331 55 1288 2 v 330 112 2 57 v 339 112 V 939 112 V 948
112 V 947 112 V 1056 95 a Fp(Datagram)13 b(Size)i(\(b)o(ytes\))p
1609 112 V 1618 112 V 948 113 671 2 v 330 168 2 57 v 339 168
V 566 151 a(V)l(ersion)p 939 168 V 948 168 V 260 w(16)p 1042
168 V 49 w(64)p 1138 168 V 49 w(250)p 1256 168 V 49 w(500)p
1373 168 V 49 w(750)p 1491 168 V 49 w(900)p 1609 168 V 1618
168 V 331 170 1288 2 v 331 172 V 330 226 2 57 v 339 226 V 365
209 a(Stateful)p 939 226 V 948 226 V 452 w(12)p 1042 226 V
49 w(14)p 1138 226 V 72 w(24)p 1256 226 V 72 w(36)p 1373 226
V 72 w(49)p 1491 226 V 72 w(56)p 1609 226 V 1618 226 V 331
228 1288 2 v 330 284 2 57 v 339 284 V 365 267 a(Stateless)f(with)h(no)g(cac)o
(he)g(hits)p 939 284 V 948 284 V 58 w(14)p 1042 284 V 49 w(17)p
1138 284 V 72 w(26)p 1256 284 V 72 w(38)p 1373 284 V 72 w(51)p
1491 284 V 72 w(58)p 1609 284 V 1618 284 V 331 286 1288 2 v
330 342 2 57 v 339 342 V 365 325 a(Stateless)f(with)h(cac)o(he)g(hits)p
939 342 V 948 342 V 121 w(14)p 1042 342 V 49 w(16)p 1138 342
V 72 w(26)p 1256 342 V 72 w(38)p 1373 342 V 72 w(51)p 1491
342 V 72 w(58)p 1609 342 V 1618 342 V 331 344 1288 2 v 331
346 V 0 424 a(T)l(able)g(4:)20 b(Pro)s(jected)15 b(round-trip)g(times)g(for)g
(the)g(lab)q(oratory)f(exp)q(erimen)o(t)i(with)f(1.0)f(Mb)o(yte/sec)h
(encryption)0 480 y(rate.)128 653 y(Figure)f(6:)20 b(Round-trip)15
b(tra)o(v)o(el)f(time)g(across)h(the)g(In)o(ternet)g(for)g(datagrams)f(of)g
(v)m(arying)h(length.)0 786 y(Mb)o(yte/sec.,)23 b(w)o(e)f(also)g(presen)o(t)h
(an)f(estimate,)h(in)f(table)g Fh(??)p Fp(,)i(of)e(the)g(round-trip)h(times)f
(attainable)f(with)0 843 y(encryption)c(at)g(the)g(realistically)d
(attainable)i(rate)g(of)h(1.0)f(Mb)o(yte/sec;)i(this)e(illustrates)f(the)j
(imp)q(ortance)e(of)0 899 y(faster)e(DES)h(hardw)o(are.)71
995 y(The)j(connection)g(setup)h(time)f(for)f(the)i(stateful)e(visa)g(proto)q
(col)h(ranged)g(from)f(30)h(to)g(40)f(ms,)i(a)o(v)o(eraging)0
1051 y(ab)q(out)f(33)f(ms.)27 b(This)17 b(n)o(um)o(b)q(er)h(represen)o(ts)g
(the)g(time)f(from)g(when)h(the)g(\014rst)f(unstamp)q(ed)i(datagram)d(is)h
(sen)o(t)0 1108 y(to)f(the)h(time)g(that)f(the)h(visa)f(arriv)o(es)g(at)h
Ff(H)762 1115 y Fe(sr)q(c)812 1108 y Fp(,)g(allo)o(wing)e(stamp)q(ed)i
(datagrams)e(to)i(b)q(e)g(sen)o(t.)25 b(The)18 b(REJECT)0 1164
y(mec)o(hanism)c(is)f(emplo)o(y)o(ed,)h(but)g(the)g(A)o(CS)g(to)f(GW)g(comm)o
(unication)g(is)h(not)f(secured)i(b)o(y)f(encryption)g(or)f(other)0
1221 y(priv)m(acy)i(mec)o(hanisms.)0 1381 y Fr(6.4)56 b(In)n(ternet)18
b(measuremen)n(ts)0 1506 y Fp(The)d(lab)q(oratory)f(Ethernet)g(has)h(higher)g
(bandwidth,)g(and)g(is)g(more)f(ligh)o(tly)f(loaded,)i(than)g(the)g(t)o
(ypical)f(in)o(ter-)0 1563 y(organizational)i(net)o(w)o(ork.)30
b(Therefore,)19 b(w)o(e)f(also)g(conducted)i(exp)q(erimen)o(ts)f(o)o(v)o(er)f
(the)h(D)o(ARP)l(A)g(In)o(ternet)g(to)0 1619 y(demonstrate)g(the)g(visa)g
(proto)q(cols)g(in)g(a)g(more)g(realistic)f(con)o(text.)32
b(The)20 b(path)f(b)q(et)o(w)o(een)h(USC)g(and)g(UCLA)0 1676
y(includes)12 b(a)g(highly-congested,)g(lo)o(w-bandwidth)f(\(56)g(Kbit/sec\))
g(hop,)i(as)e(w)o(ell)g(as)h(sev)o(eral)f(non-visa)g(gatew)o(a)o(ys.)71
1771 y(In)16 b(this)g(con\014guration,)f(not)h(only)g(is)g(the)g(a)o(v)o
(erage)f(dela)o(y)h(m)o(uc)o(h)g(higher,)g(but)g(the)h Fi(varianc)n(e)e
Fp(in)h(queueing)0 1828 y(dela)o(y)d(is)f(larger)g(than)h(the)g(di\013erence)
g(b)q(et)o(w)o(een)h(the)f(visa)f(and)h(non-visa)g(proto)q(col)f(o)o(v)o
(erheads.)18 b(Consequen)o(tly)l(,)0 1884 y(w)o(e)f(m)o(ust)g(emphasize)h
(that)e(the)i(results)f Fi(c)n(annot)f Fp(b)q(e)j(used)f(to)e(compare)i(the)f
(v)m(arious)g(visa)g(proto)q(cols)f(to)h(one)0 1941 y(another,)g(but)h(are)g
(presen)o(ted)g(primarily)e(to)h(demonstrate)g(the)g(reduced)i
(signi\014cance)f(of)f(visa)g(o)o(v)o(erhead)g(in)0 1997 y(the)e(con)o(text)g
(of)g(other)f(sources)i(of)e(net)o(w)o(ork)h(dela)o(y)l(.)71
2093 y(In)h(order)g(to)f(obtain)h(the)g(most)f(meaningful)g(a)o(v)o(erage)g
(v)m(alues)h(for)g(visa)f(and)h(non-visa)g(proto)q(cols,)e(w)o(e)i(ran)0
2149 y(suites)i(of)f(measuremen)o(ts)h(at)f(di\013eren)o(t)g(times)h(of)f
(the)h(da)o(y)g(and)g(w)o(eek)g(in)g(searc)o(h)g(of)f(a)h(p)q(erio)q(d)g(of)g
(relativ)o(ely)0 2206 y(lo)o(w)d(dela)o(y)h(v)m(ariance.)23
b(The)17 b(n)o(um)o(b)q(ers)f(presen)o(ted)h(in)f(table)g Fh(??)23
b Fp(\(and)16 b(graphically)f(in)h(\014gure)g Fh(??)p Fp(\))23
b(are)16 b(from)f(a)0 2262 y(suite)e(run)g(during)g(a)g(three)g(hour)g(in)o
(terv)m(al)g(when)g(dela)o(y)g(v)m(aried)g(least.)18 b(In)c(addition,)e(w)o
(e)h(excluded)h(the)f(highest)0 2319 y(dela)o(y)i(v)m(alues)g(when)h
(calculating)e(the)h(a)o(v)o(erages)f(for)g(eac)o(h)i(proto)q(col.)71
2414 y(These)e(measuremen)o(ts)f(ma)o(y)g(understate)h(the)f(cost)h(of)f
(visa)g(proto)q(cols,)f(since)i(the)g(encryption)g(op)q(erations)0
2471 y(in)o(v)o(olv)o(ed)19 b(w)o(ere)h(probably)f(b)q(eing)i(p)q(erformed)f
(in)g(parallel)e(with)i(the)g(transmission)e(of)i(other)f(pac)o(k)o(ets)h(o)o
(v)o(er)0 2527 y(a)d(congested)h(link.)27 b(In)18 b(an)g(uncongested)g(net)o
(w)o(ork,)f(through)h(gatew)o(a)o(ys)e(that)h(handle)g(only)h(visa-con)o
(trolled)0 2584 y(datagrams,)f(this)g(parallelism)f(migh)o(t)g(not)i(b)q(e)g
(a)o(v)m(ailable,)f(and)h(the)g(additional)f(end-to-end)i(dela)o(y)e(imp)q
(osed)0 2640 y(b)o(y)e(the)g(visa)g(proto)q(cols)f(could)h(b)q(e)h(as)f
(large)f(as)h(it)f(is)h(in)g(our)g(lab)q(oratory)e(exp)q(erimen)o(ts.)952
2828 y(24)p eop
%%Page: 25 25
bop 308 55 1334 2 v 307 112 2 57 v 316 112 V 916 112 V 925
112 V 925 112 V 1056 95 a Fp(Datagram)13 b(Size)j(\(b)o(ytes\))p
1633 112 V 1642 112 V 925 113 717 2 v 307 168 2 57 v 316 168
V 543 151 a(V)l(ersion)p 916 168 V 925 168 V 283 w(16)p 1043
168 V 72 w(64)p 1161 168 V 49 w(250)p 1279 168 V 49 w(500)p
1397 168 V 49 w(750)p 1515 168 V 49 w(900)p 1633 168 V 1642
168 V 308 170 1334 2 v 308 172 V 307 226 2 57 v 316 226 V 342
209 a(Without)e(VISA)p 916 226 V 925 226 V 316 w(120)p 1043
226 V 49 w(149)p 1161 226 V 49 w(280)p 1279 226 V 49 w(441)p
1397 226 V 49 w(609)p 1515 226 V 49 w(696)p 1633 226 V 1642
226 V 308 228 1334 2 v 307 284 2 57 v 316 284 V 342 267 a(Stateful)g(without)
g(encryption)p 916 284 V 925 284 V 58 w(131)p 1043 284 V 49
w(172)p 1161 284 V 49 w(298)p 1279 284 V 49 w(468)p 1397 284
V 49 w(616)p 1515 284 V 49 w(706)p 1633 284 V 1642 284 V 308
286 1334 2 v 307 342 2 57 v 316 342 V 342 325 a(Stateful)p
916 342 V 925 342 V 452 w(138)p 1043 342 V 49 w(176)p 1161
342 V 49 w(316)p 1279 342 V 49 w(478)p 1397 342 V 49 w(631)p
1515 342 V 49 w(719)p 1633 342 V 1642 342 V 308 344 1334 2
v 307 400 2 57 v 316 400 V 342 383 a(Stateless)g(with)g(no)i(cac)o(he)f(hits)
p 916 400 V 925 400 V 58 w(190)p 1043 400 V 49 w(228)p 1161
400 V 49 w(342)p 1279 400 V 49 w(507)p 1397 400 V 49 w(661)p
1515 400 V 49 w(745)p 1633 400 V 1642 400 V 308 402 1334 2
v 332 479 a(T)l(able)g(5:)20 b(Round-trip)15 b(datagram)f(times)g(for)h(the)g
(In)o(ternet)h(exp)q(erimen)o(t)0 658 y Fr(6.5)56 b(Analysis)0
783 y Fp(Our)21 b(results)f(demonstrate)g(the)g(function)h(of)f(the)h
(stateful)e(and)i(stateless)e(proto)q(cols)h(in)g(b)q(oth)h(lab)q(oratory)0
839 y(and)14 b(actual)g(in)o(ter-organizational)c(in)o(ternet)k(arrangemen)o
(ts.)k(They)d(sho)o(w)e(that,)g(while)h(the)g(o)o(v)o(erhead)g(for)f(our)0
895 y(implemen)o(tation)g(is)i(signi\014can)o(t,)f(it)g(is)h(not)g
(prohibitiv)o(e.)71 991 y(The)c(lab)q(oratory)f(results)h(pro)o(vide)g(a)g
(basis)g(for)g(comparing)g(the)h(proto)q(cols)e(to)h(one)h(another.)18
b(They)12 b(con\014rm)0 1048 y(our)22 b(prediction)g(that)f(the)i(stateless)e
(proto)q(col)g(p)q(erforms)h(nearly)g(as)g(w)o(ell)f(as)h(the)g(stateful)f
(one,)j(on)e(p)q(er-)0 1104 y(datagram)16 b(dela)o(y)l(,)h(only)g(when)h(the)
f(cac)o(he-hit)g(rate)g(is)g(reasonably)f(high.)27 b(\(In)17
b(the)h(op)q(erating)e(region)h(where)0 1160 y(the)f(n)o(um)o(b)q(er)h(of)f
(activ)o(e)f(con)o(v)o(ersations)g(is)g(greater)h(than)g(the)g(size)g(of)g(a)
g(gatew)o(a)o(y's)e(visa-table,)h(the)h(stateless)0 1217 y(proto)q(col)f(ma)o
(y)h(p)q(erform)h(b)q(etter)f(than)g(the)h(stateful)e(proto)q(col.\))23
b(These)17 b(results)f(also)f(sho)o(w)h(that)g(comparing)0
1273 y(the)h(cost)f(of)g(connection)h(setup)g(in)f(the)h(stateful)f(proto)q
(col)f(to)h(the)h(cost)f(of)h(setting)e(up)i(cac)o(he)g(en)o(tries)f(in)h
(the)0 1330 y(stateless)c(proto)q(col,)g(for)h(connections)h(in)o(v)o(olving)
d(only)i(a)g(few)h(datagrams,)d(the)j(stateless)e(proto)q(col)h(ma)o(y)f(ha)o
(v)o(e)0 1386 y(a)i(small)f(edge.)20 b(In)c(the)g(steady)f(state,)f(the)h
(di\013erence)g(in)h(dela)o(y)e(of)h(appro)o(ximately)f(2)h(msec)g(p)q(er)h
(datagram)d(is)0 1443 y(due)j(to)e(the)i(additional)d(length)i(of)g
(stateless-proto)q(col)e(visa)i(options.)71 1538 y(The)h(In)o(ternet)h
(results)f(demonstrate)g(that)g(when)h(visa)f(mec)o(hanisms)g(are)g(added)h
(to)f(subsets)h(of)f(existing)0 1595 y(In)o(ternet)k(gatew)o(a)o(ys)e(and)i
(hosts)g(b)q(oth)f(v)m(ariations)g(of)g(the)h(proto)q(col)f(w)o(ork)g
(without)g(in)o(terfering)f(with)i(non-)0 1651 y(visa,)e(lo)q(cal)g(net)o(w)o
(ork)g(or)g(in)o(ternet,)h(op)q(erations.)29 b(These)19 b(results)g(also)e
(demonstrate)h(that)g(the)h(o)o(v)o(erhead)f(of)0 1708 y(visa)c(proto)q(cols)
f(is)i(m)o(uc)o(h)f(less)h(signi\014can)o(t)e(in)i(high-dela)o(y)f(en)o
(vironmen)o(ts.)19 b(The)c(results)f(from)g(the)h(lab)q(oratory)0
1764 y(exp)q(erimen)o(ts)j(pro)o(vide)g(an)h(upp)q(er)g(b)q(ound)h(on)e(the)g
(o)o(v)o(erhead)g(of)g(visa)g(proto)q(cols;)h(the)f(relativ)o(e)f(o)o(v)o
(erhead)h(in)0 1821 y(actual)h(in)o(ter-organizational)e(net)o(w)o(orks)j
(will)e(b)q(e)j(lo)o(w)o(er,)f(since)g(o)o(v)o(er)g(suc)o(h)g(paths)g(the)h
(dela)o(ys)e(due)i(to)f(visa)0 1877 y(proto)q(cols)13 b(sta)o(y)g(\014xed,)i
(while)e(dela)o(ys)h(due)h(to)e(transmission)g(and)h(gatew)o(a)o(y)e(pro)q
(cessing)i(generally)g(are)g(higher.)71 1973 y(The)e(critical)e(prerequisite)
i(for)g(practical)e(application)h(of)h(visa)f(proto)q(cols)g(is)h(faster)f
(encryption)h(hardw)o(are.)0 2029 y(If)i(encryption)g(rates)e(are)i(not)f
(impro)o(v)o(ed)g(b)o(y)h(an)f(order)g(of)h(magnitude)f(o)o(v)o(er)g(that)g
(of)g(the)h(equipmen)o(t)f(w)o(e)h(used,)0 2086 y(visa-related)c(encryption)h
(pro)q(cessing)g(will)e(presen)o(t)i(an)g(o)o(v)o(erwhelming)f(burden)i(to)e
(high-sp)q(eed)i(gatew)o(a)o(ys)e(that)0 2142 y(can)15 b(otherwise)f(pro)q
(cess)h(sev)o(eral)f(thousand)g(pac)o(k)o(ets)g(p)q(er)i(second.)k(W)l(e)15
b(b)q(eliev)o(e)f(that)g(acceptable)h(encryption)0 2198 y(rates)f(are)h
(feasible)g(with)g(curren)o(t)g(tec)o(hnology)l(.)0 2380 y
Fj(7)69 b(Other)22 b(design)h(issues)0 2520 y Fp(Sev)o(eral)15
b(other)g(design)g(issues)g(are)g(listed)f(b)q(elo)o(w)h(and)g(are)g
(discussed)h(in)f(more)g(detail)f(in)h([)p Fh(?)p Fp(].)68
2647 y Fg(\017)23 b Fh(Access)16 b(Con)o(trol)h(and)h(Denial)f(of)g(Service)p
Fp(:)114 2704 y(Ov)o(erall)f(securit)o(y)i(of)f(an)h(organization's)d(net)o
(w)o(ork)i(dep)q(ends)i(up)q(on)g(A)o(CS)e(to)h(host)f(and)h(GW)f(comm)o(u-)
952 2828 y(25)p eop
%%Page: 26 26
bop 114 45 a Fp(nication)19 b(securit)o(y)l(.)36 b(There)21
b(is)f(also)g(the)h(p)q(ossibilit)o(y)e(of)h(denial)g(of)h(service)f(through)
h(harassmen)o(t)e(of)114 102 y(A)o(CSs)12 b(with)h(REQUEST)g(messages.)19
b(In)14 b(addition,)e(visa)g(proto)q(cols)g(do)g(not)h(prev)o(en)o(t)g(all)f
(repla)o(y)g(of)g(v)m(alid)114 158 y(messages)i(\(if)h(done)g(while)g(a)g
(visa)f(k)o(ey)h(is)g(v)m(alid\).)68 252 y Fg(\017)23 b Fh(Reducing)17
b(the)h(cost)g(of)f(connection)h(setup)114 308 y Fp(The)e(actual)e(cost)i(of)
f(connection)h(setup)g(dep)q(ends)h(up)q(on)f(ho)o(w)g(an)f(organization)f(c)
o(ho)q(oses)i(to)f(con\014gure)114 365 y(its)f(A)o(CS.)g(F)l(or)g(example,)h
(w)o(e)f(assume)h(that)f(t)o(w)o(o-w)o(a)o(y)f(visas)h(are)h(allo)q(cated)e
(automatically)l(.)18 b(If)d(one)g(w)o(a)o(y)114 421 y(visas)f(are)h(used)h
(the)f(cost)g(of)f(connection)i(setup)f(will)f(b)q(e)i(doubled.)68
515 y Fg(\017)23 b Fh(Protecting)17 b(transit)g(organizations)114
571 y Fp(T)l(ransit)10 b(organizations)f(are)j(vulnerable)f(if)g(in)o(ternal)
f(hosts)h(accept)h(datagrams)e(not)h(addressed)h(to)e(them.)114
628 y(A)16 b(transit)f(organization)g(ma)o(y)h(b)q(e)h(protected)f(through)g
(the)h(use)g(of)f(encryption-based)h(encapsulation)114 684
y(as)d(the)i(datagram)d(tra)o(v)o(erses)h(the)i(transit)d(net.)68
778 y Fg(\017)23 b Fh(Visas)16 b(and)i(fragmen)o(tation)114
835 y Fp(The)c(visa)g(proto)q(cols)g(describ)q(ed)h(mak)o(e)f(use)h(of)f
(data)g(signatures.)19 b(F)l(ragmen)o(tation)12 b(results)i(in)h(a)f(c)o
(hange)114 891 y(in)20 b(\(that)f(is,)i(truncation)e(of)t(\))g(the)h(data)g
(con)o(ten)o(ts)f(of)h(a)g(pac)o(k)o(et.)35 b(Ho)o(w)o(ev)o(er,)20
b(fragmen)o(tation)e(can)i(b)q(e)114 948 y(accommo)q(dated)15
b(if)f(necessary)i(\(see)f([)p Fh(?)p Fp(,)f Fh(?)p Fp(]\).)68
1041 y Fg(\017)23 b Fh(Co)o(v)o(ert)15 b(c)o(hannels)i(via)g(header)h
(\014elds)114 1098 y Fp(A)f(data)g(signature)g(metho)q(d)h(m)o(ust)f(co)o(v)o
(er)g(not)g(only)g(the)h(data)f(segmen)o(t,)g(but)h(an)o(y)f(datagram)g
(header)114 1154 y(\014elds)j(whose)h(authen)o(ticit)o(y)e(cannot)h(b)q(e)h
(c)o(hec)o(k)o(ed)g(b)o(y)g(the)f(gatew)o(a)o(ys.)34 b(An)o(y)21
b(unc)o(hec)o(k)o(ed)g(\014eld)g(lea)o(v)o(es)114 1211 y(a)c(p)q(oten)o(tial)
g(co)o(v)o(ert)g(c)o(hannel,)h(since)h(a)e(malicious)g(host)g(could)h(cop)o
(y)g(a)g(v)m(alid)f(datagram,)g(c)o(hange)h(the)114 1267 y(unc)o(hec)o(k)o
(ed)g(\014eld,)g(and)g(send)g(the)g(mo)q(di\014ed)g(cop)o(y)f(without)f
(raising)h(suspicion.)26 b(It)18 b(is)f(easy)g(to)g(reduce)114
1324 y(the)d(bandwidth)h(of)f(this)h(c)o(hannel)f(to)g(only)h(a)f(few)h(bits)
f(p)q(er)h(pac)o(k)o(et;)f(it)g(is)g(nearly)g(imp)q(ossible)g(to)g(reduce)114
1380 y(it)g(further.)68 1474 y Fg(\017)23 b Fh(Implications)16
b(for)h(In)o(ternet)g(gatew)o(a)o(y)g(design)114 1530 y Fp(Com)o(bining)k
(the)h(functions)g(of)g(a)g(con)o(v)o(en)o(tional)e(In)o(ternet)j(gatew)o(a)o
(y)d(with)i(that)f(of)h(a)g(visa-gatew)o(a)o(y)114 1587 y(represen)o(ts)11
b(a)f(c)o(hallenge)h(to)f(gatew)o(a)o(y)f(designers.)19 b(The)11
b(increased)g(n)o(um)o(b)q(er)g(of)g(p)q(ossible)f(error)h(conditions)114
1643 y(and)22 b(cost)g(of)h(encryption)f(pro)q(cessing)g(o)o(v)o(erhead)h
(mak)o(es)f(ac)o(hiev)o(emen)o(t)g(of)g(high)g(throughput)g(more)114
1700 y(di\016cult.)0 1882 y Fj(8)69 b(Conclusions)0 2023 y
Fp(W)l(e)21 b(ha)o(v)o(e)f(describ)q(ed)i(t)o(w)o(o)d(v)m(ariations)g(on)i
(the)g(original)e(visa)g(sc)o(heme[)p Fh(?)p Fp(])37 b(for)20
b(con)o(trolling)e(datagram)h(\015o)o(w)0 2079 y(b)q(et)o(w)o(een)i
(organizations.)33 b(The)21 b(\014rst)f(in)o(v)o(olv)o(es)f(direct)h
(transfer)g(of)g(authen)o(tication)f(information)g(b)q(et)o(w)o(een)0
2136 y(A)o(CSs)d(and)g(gatew)o(a)o(ys,)e(state)h(main)o(tenance)h(in)g(the)g
(gatew)o(a)o(ys,)e(and)j(a)e(cryptographic)h(mec)o(hanism)f(to)h(mark)0
2192 y(authorized)d(datagrams.)k(In)d(the)f(second)g(v)m(ariation,)e(authen)o
(tication)h(information)f(is)h(\\piggybac)o(k)o(ed")g(on)h(the)0
2249 y(con)o(trolled)18 b(datagrams,)h(rather)f(than)i(directly)e(comm)o
(unicated)h(b)q(et)o(w)o(een)h(A)o(CSs)f(and)h(gatew)o(a)o(ys,)e(and)i(the)0
2305 y(gatew)o(a)o(ys)d(main)o(tain)g(cac)o(hes)h(rather)g(than)g(true)h
(databases.)28 b(The)19 b(t)o(w)o(o)e(proto)q(cols)h(v)m(ary)g(in)g(the)h(n)o
(um)o(b)q(er)f(of)0 2361 y(pac)o(k)o(ets)d(required)h(to)g(authorize)f(a)h
(connection,)g(their)f(b)q(eha)o(vior)h(under)g(load)g(and)g(during)g
(failure)f(reco)o(v)o(ery)l(,)0 2418 y(and)j(the)f(amoun)o(t)g(of)g
(encryption)h(p)q(erformed)g(on)f(eac)o(h)h(datagram;)f(exp)q(erimen)o(tal)g
(results)g(illustrate)f(these)0 2474 y(tradeo\013s.)71 2570
y(Adaptation)h(of)i(visas)f(in)h(actual)f(in)o(ternet)o(w)o(orks)f(dep)q
(ends)j(on)f(sev)o(eral)f(prerequisites:)27 b(resolution)18
b(of)g(a)0 2626 y(few)j(design)g(c)o(hoices)g(and)h(parameters,)f(the)g
(widespread)h(a)o(v)m(ailabilit)o(y)c(of)j(inexp)q(ensiv)o(e,)i(fast,)e(and)g
(secure)0 2683 y(cryptosystems,)e(and)g(su\016cien)o(t)g(co)q(ordination)f
(among)g(organizations)f(to)i(mak)o(e)f(the)h(system)g(w)o(orth)o(while.)952
2828 y(26)p eop
%%Page: 27 27
bop 0 45 a Fp(Visas)12 b(are)h(at)g(b)q(est)g(a)g(robust)g
Fi(me)n(chanism)f Fp(for)h(enforcing)f(information)g(\015o)o(w)g(con)o(trol)g
Fi(p)n(olicies)p Fp(;)h(the)g(c)o(hoice)g(and)0 102 y(sp)q(eci\014cation)i
(of)g(these)g(p)q(olicies)g(will)f(presen)o(t)h(di\016cult)g(and)g(in)o
(teresting)f(problems.)0 283 y Fj(9)69 b(Ac)n(kno)n(wledgemen)n(ts)0
424 y Fp(Our)21 b(thanks)g(to)f(n)o(umerous)g(colleagues)g(in)h(the)g(In)o
(ternet)f(comm)o(unit)o(y)g(for)g(their)g(commen)o(ts)h(on)f(previous)0
480 y(drafts,)h(including:)31 b(Bob)22 b(Braden,)g(Annette)f(de)h(Sc)o(hon,)g
(Mic)o(hael)e(Sc)o(hro)q(eder,)j(Rob)q(ert)e(Sansom)g(and)g(the)0
536 y(anon)o(ymous)15 b(reviews.)71 632 y(P)o(articular)k(appreciation)i(to:)
33 b(Kamal)21 b(Anand)h(for)f(implemen)o(ting)g(the)h(In)o(ternet)g(exp)q
(erimen)o(ts,)h(P)o(aul)0 688 y(Crumley)17 b(of)g(the)h(Carnegie)f(Mellon)g
(Univ)o(ersit)o(y)f(ITC)i(for)f(making)g(a)o(v)m(ailable)f(the)i(DES)f(hardw)
o(are)g(and)h(as-)0 745 y(sisting)12 b(us)h(in)g(putting)g(it)f(to)g(w)o
(ork,)h(Mark)f(LaRouc)o(he)i(of)e(UCLA)i(for)e(pro)o(viding)g(temp)q(orary)h
(access)g(to)g(UCLA)0 801 y(net)o(w)o(ork)d(facilities)e(in)j(supp)q(ort)g
(of)f(our)h(In)o(ternet)g(exp)q(erimen)o(ts,)g(and)g(to)f(Mark)g(Bro)o(wn)g
(of)g(the)h(USC)g(Computing)0 858 y(Services)k(for)g(helping)g(to)g
(con\014gure)g(our)g(exp)q(erimen)o(tal)g(lab)q(oratory)e(in)o(ternet.)0
1039 y Fj(References)445 1158 y Fp([1])21 b(D.)16 b(W.)h(Da)o(vies)e(and)i
(W.)f(L.)h(Price,)g Fi(Se)n(curity)g(F)m(or)g(Computer)i(Networks)p
Fp(,)d Fh(New)515 1215 y(Y)l(ork,)g(NY:)g(Wiley)p Fp(,)e(1984.)445
1306 y([2])21 b(W.)d(Di\016e,)f Fi(The)i(First)f(T)m(en)f(Y)m(e)n(ars)g(of)i
(Public-Key)g(Crypto)n(gr)n(aphy)p Fp(,)g Fh(Pro)q(ceed-)515
1363 y(ings)e(of)h(the)f(IEEE)p Fp(,)f(v)o(ol.)e(76,)g(No.)h(5,)f(pp.)i
(560-577,)d(Ma)o(y)h(1988.)445 1455 y([3])21 b(W.)e(Di\016e)g(and)g(M.)g(E.)g
(Hellman,)g Fi(New)h(Dir)n(e)n(ctions)f(in)h(Crypto)n(gr)n(aphy)p
Fp(,)g Fh(IEEE)515 1511 y(T)l(ransactions)h(on)h(Information)e(Theory)p
Fp(,)f(v)o(ol.)e(IT-22,)h(No.)g(11,)g(pp.)h(644-)515 1568 y(654,)14
b(No)o(v)o(em)o(b)q(er,)h(1976.)445 1659 y([4])21 b(D.)d(Estrin)f(and)h(G.)f
(Tsudik,)h Fi(Visa)h(Scheme)f(for)h(Inter-Or)n(ganization)f(Network)515
1716 y(Se)n(curity)p Fp(,)13 b(IEEE,)h Fh(Pro)q(ceedings)g(of)i(the)g(IEEE)g
(Symp)q(osium)e(on)h(Securit)o(y)515 1772 y(and)j(Priv)m(acy)p
Fp(,)c(pp.)h(174-183,)e(April,)i(1987.)445 1864 y([5])21 b(D.)29
b(Estrin,)i Fi(Inter)n(c)n(onne)n(ction)26 b(Pr)n(oto)n(c)n(ols)i(for)h
(Inter)n(or)n(ganization)e(Networks)p Fp(,)515 1920 y(IEEE)21
b(Journal)e(on)h(Selected)g(Areas)g(in)g(Comm)o(unications,)f(V)l(ol.)g(SA)o
(C-5,)i(No.)515 1977 y(9,)15 b(pp.)g(1480-1491,)e(Decem)o(b)q(er)j(1987.)445
2069 y([6])21 b(D.)12 b(Estrin,)f(J.)h(Mogul,)g(G.)f(Tsudik,)h(K.)g(Anand,)h
Fi(Visa)g(Pr)n(oto)n(c)n(ols)g(for)h(Contr)n(ol)r(ling)515
2125 y(Inter-Or)n(ganization)h(Datagr)n(am)j(Flow:)j(Extende)n(d)16
b(Description)p Fp(,)f(Univ)o(ersit)o(y)f(of)515 2181 y(Southern)22
b(California,)d(Computer)h(Science)i(Departmen)o(t,)f(T)l(ec)o(hnical)g(Rep)q
(ort)515 2238 y(TR)16 b(88-50,)e(Decem)o(b)q(er)h(1988.)445
2330 y([7])21 b(D.)c(Estrin)g(and)h(G.)f(Tsudik,)h Fi(Se)n(curity)h(Issues)e
(in)h(Policy)g(R)n(outing)p Fp(,)g(Univ)o(ersit)o(y)515 2386
y(of)13 b(Southern)g(California,)e(Computer)h(Science)i(Departmen)o(t,)e(T)l
(ec)o(hnical)h(Rep)q(ort)515 2443 y(TR)j(88-54,)e(Decem)o(b)q(er)h(1988.)445
2534 y([8])21 b(J.)g(G.)f(Fletc)o(her)h(and)g(R.)g(W.)f(W)l(atson,)h
Fi(Me)n(chanisms)f(for)i(a)g(R)n(eliable)e(Timer-)515 2591
y(b)n(ase)n(d)j(Pr)n(oto)n(c)n(ol)p Fp(,)g Fh(Computer)j(Net)o(w)o(orks)p
Fp(,)c(v)o(ol.)f(2,)j(No.)f(4/5,)g(pp.)g(271-290,)515 2647
y(Septem)o(b)q(er/Octob)q(er,)f(1978,)d(\(Also)f(in)i Fi(Pr)n(o)n(c.)f
(Computer)i(Network)g(Pr)n(oto)n(c)n(ols)515 2704 y(Symp)n(osium)16
b Fp(C5.1-C5.17,)c(F)l(ebruary)j(1978.\))952 2828 y(27)p eop
%%Page: 28 28
bop 445 45 a Fp([9])21 b(C.)11 b(Ken)o(t)f(and)h(J.)g(Mogul,)f
Fi(F)m(r)n(agmentation)h(Consider)n(e)n(d)g(Harmful)p Fp(,)h
Fh(Pro)q(ceedings)515 102 y(of)18 b(the)g(A)o(CM)e(SIGCOMM)g(1987)p
Fp(,)g(pp.390-401,)d(August,)i(1987.)422 195 y([10])21 b(J.)13
b(Mracek,)f Fi(Network)j(A)n(c)n(c)n(ess)d(Contr)n(ol)h(in)g(Multi-Net)h
(Internet)f(T)m(r)n(ansp)n(ort)p Fp(,)e(S.B.)515 252 y(Thesis,)k(M.I.T.)f
(Departmen)o(t)h(of)g(Electrical)e(Engineering)i(and)h(Computer)f(Sci-)515
308 y(ence,)h(1983,)e(June.)422 402 y([11])21 b Fi(A)n(dvanc)n(e)n(d)k(Micr)n
(o)g(Devic)n(es)g(MOS)g(Micr)n(opr)n(o)n(c)n(essors)f(and)i(Peripher)n(als)f
(Data)515 459 y(Bo)n(ok.)p Fp(,)15 b(Adv)m(anced)i(Micro)d(Devices,)h(Inc.,)g
(Sunn)o(yv)m(ale,)g(CA.)g(1987)422 552 y([12])21 b Fi(F)m(e)n(der)n(al)11
b(Information)h(Pr)n(o)n(c)n(essing)e(Standar)n(ds)p Fp(,)h(National)e
(Bureau)i(of)f(Standards,)515 609 y(Publication)k(46,)h(1977.)422
703 y([13])21 b(R.)h(M.)f(Needham)h(and)g(M.)f(D.)g(Sc)o(hro)q(eder,)j
Fi(Using)d(Encryption)g(for)i(A)o(uthen-)515 759 y(tic)n(ation)18
b(in)g(L)n(ar)n(ge)f(Networks)i(of)f(Computers)p Fp(,)g Fh(CA)o(CM)p
Fp(,)d(v)o(ol.)h(21,)h(No.)g(12,)g(pp.)515 816 y(993-998,)11
b(Decem)o(b)q(er,)i(1978)f(\(note)g(Also)f(CSL-78-4,)i(Xero)o(x)f(P)o(alo)f
(Alto)g(Researc)o(h)515 872 y(Cen)o(ter,)k(Septem)o(b)q(er)h(1978\))422
966 y([14])21 b(R.)c(M.)g(Needham)g(and)g(M.)g(D.)f(Sc)o(hro)q(eder,)i
Fi(A)o(uthentic)n(ation)f(R)n(evisite)n(d)p Fp(,)f Fh(Op)q(er-)515
1022 y(ating)i(Systems)e(Review)p Fp(,)e(v)o(ol.)g(21,)g(No.7,)g(pg.7,)g(Jan)
o(uary)l(,)h(1987.)422 1116 y([15])21 b(M.)12 b(A.)g(P)o(adlipsky)l(,)g
Fi(A)i(Persp)n(e)n(ctive)e(on)i(the)g(ARP)m(ANET)e(R)n(efer)n(enc)n(e)g(Mo)n
(del)p Fp(,)g(SRI-)515 1173 y(NIC,)k(No.)e(871,)g(RF)o(C,)h(Septem)o(b)q(er,)
g(1982.)422 1266 y([16])21 b(J.)16 b(P)o(ostel,)d Fi(Internet)i(Pr)n(oto)n(c)
n(ol)p Fp(,)f(NIC,)h(RF)o(C)g(No.)g(791,)f(Septem)o(b)q(er)i(1981.)422
1360 y([17])21 b(J.)12 b(P)o(ostel,)e Fi(Internet)h(Contr)n(ol)h(Message)f
(Pr)n(oto)n(c)n(ol)p Fp(,)g(NIC,)g(RF)o(C)g(No.)g(792,)f(Septem-)515
1417 y(b)q(er)16 b(1981.)422 1510 y([18])21 b(R.)c(Riv)o(est,)f(A.)g(Shamir,)
f(and)i(L.)f(Adelman,)g Fi(A)i(Metho)n(d)f(for)h(Obtaining)e(Digital)515
1567 y(Signatur)n(es)k(and)g(Public-key)h(Cryptosystems)p Fp(,)e
Fh(CA)o(CM)p Fp(,)f(v)o(ol.)g(21,)i(No.)g(2,)g(pp.)515 1623
y(120-126,)14 b(F)l(ebruary)l(,)h(1978.)422 1717 y([19])21
b(A.)j(T)l(anen)o(baum,)h Fi(Computer)g(Networks)p Fp(,)g(Pren)o(tice-Hall,)f
(Englew)o(o)q(o)q(d)f(Cli\013s,)515 1774 y(N.J.,)15 b(1981.)422
1867 y([20])21 b(G.)14 b(Tsudik,)g Fi(Internet)g(Datagr)n(am)j(A)o(uthentic)n
(ation:)j(Implic)n(ations)14 b(of)i(F)m(r)n(agmen-)515 1924
y(tation)e(and)g(Dynamic)g(R)n(outing)p Fp(,)f(T)l(o)f(app)q(ear)h(in)f(IEEE)
h(Journal)f(on)h(Selected)g(Ar-)515 1980 y(eas)i(in)g(Comm)o(unications,)f
(Sp)q(ecial)h(Issue)h(on)f(Secure)h(Comm)o(unications,)d(1989.)422
2074 y([21])21 b(R.)e(W.)e(W)l(atson,)h Fi(Delta-T)h(Pr)n(oto)n(c)n(ol)f(Pr)n
(eliminary)g(Sp)n(e)n(ci\014c)n(ation)p Fp(,)f(UCRL,)i(No.)515
2131 y(52881,)14 b(La)o(wrence)h(Liv)o(ermore)g(Lab)q(oratory)l(,)f(No)o(v)o
(em)o(b)q(er,)g(1979.)422 2224 y([22])21 b(H.)15 b(Zimmermann,)f
Fi(OSI)i(R)n(efer)n(enc)n(e)e(Mo)n(del)i(-)g(The)g(ISO)f(Mo)n(del)h(of)h(A)o
(r)n(chite)n(ctur)n(e)515 2281 y(for)j(Op)n(en)e(Systems)g(Inter)n(c)n(onne)n
(ction)p Fp(,)d Fh(IEEE)22 b(T)l(ransactions)e(on)h(Comm)o(u-)515
2337 y(nication)p Fp(,)15 b(v)o(ol.)f(COM-28,)h(pp.)g(425-432,)e(April)i
(1980.)952 2828 y(28)p eop
%%Trailer
end
userdict /end-hook known{end-hook}if
%%EOF