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