Crypto2000wasthe20thAnnualCryptoconference. Itwassponsoredbythe InternationalAssociationforCryptologicResearch(IACR)incooperationwith theIEEEComputerSocietyTechnicalCommitteeonSecurityandPrivacyand theComputerScienceDepartmentoftheUniversityofCaliforniaatSantaB- bara. Theconferencereceived120submissions,andtheprogramcommittee- lected32oftheseforpresentation. Extendedabstractsofrevisedversionsof thesepapersareintheseproceedings. Theauthorsbearfullresponsibilityfor thecontentsoftheirpapers. Theconferenceprogramincludedtwoinvitedlectures. DonCoppersmith s presentation ThedevelopmentofDES recordedhisinvolvementwithoneof themostimportantcryptographicdevelopmentsever,namelytheDataEncr- tionStandard,andwasparticularlyaptgiventheimminentselectionofthe AdvancedEncryptionStandard. Mart ?nAbadi spresentation Tamingthe- versary wasaboutbridgingthegapbetweenusefulbutperhapssimplisticthreat abstractionsandrigorousadversarialmodels,orperhaps,evenmoregenerally, betweenviewpointsofthesecurityandcryptographycommunities. Anabstract correspondingtoMart ?n stalkisincludedintheseproceedings. Theconferenceprogramalsoincludeditstraditional rumpsession ofshort, informalorimpromptupresentations,chairedthistimebyStuartHaber. These presentationsarenotre?ectedintheseproceedings. Anelectronicsubmissionprocesswasavailableandrecommended,butforthe ?rsttimeusedawebinterfaceratherthanemail. (Perhapsasaresult,therewere nohardcopysubmissions. )Thesubmissionreviewprocesshadthreephases. In the?rstphase,programcommitteememberscompiledreports(assistedattheir discretionbysub-refereesoftheirchoice,butwithoutinteractionwithother programcommitteemembers)andenteredthem,viawebforms,intoweb-review softwarerunningatUCSD. Inthesecondphase,committeemembersusedthe softwaretobrowseeachother sreports,discuss,andupdatetheirownreports. Lastlytherewasaprogramcommitteemeetingtodiscussthedi?cultcases. Iamextremelygratefultotheprogramcommitteemembersfortheiren- mousinvestmentoftime,e?ort,andadrenalineinthedi?cultanddelicate processofreviewandselection. (Alistofprogramcommitteemembersands- refereestheyinvokedcanbefoundonsucceedingpagesofthisvolume. )Ialso thanktheauthorsofsubmittedpapers inequalmeasureregardlessofwhether theirpaperswereacceptedornot fortheirsubmissions. Itistheworkofthis bodyofresearchersthatmakesthisconferencepossible. IthankRebeccaWrightforhostingtheprogramcommitteemeetingatthe AT&TbuildinginNewYorkCityandmanagingthelocalarrangements,and RanCanettifororganizingthepost-PC-meetingdinnerwithhischaracteristic gastronomicandoenophilic?air. VI Preface Theweb-reviewsoftwareweusedwaswrittenforEurocrypt2000byWim MoreauandJorisClaessensunderthedirectionofEurocrypt2000programchair BartPreneel,andIthankthemforallowingustodeploytheirusefulandcolorful tool. IammostgratefultoChanathipNamprempre(aka. Meaw)whoprovided systems,logistical,andmoralsupportfortheentireCrypto2000process. She wrotethesoftwarefortheweb-basedsubmissions,adaptedandranthew- reviewsoftwareatUCSD,andcompiledthe?nalabstractsintotheproceedings youseehere. ShetypesfasterthanIspeak. IamgratefultoHugoKrawczykforhisinsightandadvice,providedovera longperiodoftimewithhisusualcombinationofhonestyandcharm,andto himandotherpastprogramcommitteechairs,mostnotablyMichaelWiener andBartPreneel,forrepliestothehostofquestionsIposedduringthep- cess. InadditionIreceivedusefuladvicefrommanymembersofourcommunity includingSilvioMicali,TalRabin,RonRivest,PhilRogaway,andAdiShamir. FinallythankstoMattFranklinwhoasgeneralchairwasinchargeofthelocal organizationand?nances,and,ontheIACRside,toChristianCachin,Kevin McCurley,andPaulVanOorschot. ChairingaCryptoprogramcommitteeisalearningprocess. Ihavecometo appreciateevenmorethanbeforethequalityandvarietyofworkinour?eld, andIhopethepapersinthisvolumecontributefurthertoitsdevelopment. June2000 MihirBellare ProgramChair,Crypto2000 CRYPTO2000 August20 24,2000,SantaBarbara,California,USA Sponsoredbythe InternationalAssociationforCryptologicResearch(IACR) incooperationwith IEEEComputerSocietyTechn