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 IEEEComputerSocietyTechnicalCommitteeonSecurityandPrivacy, ComputerScienceDepartment,UniversityofCalifornia,SantaBarbara GeneralChair MatthewFranklin,XeroxPaloAltoResearchCenter,USA ProgramChair MihirBellare,UniversityofCalifornia,SanDiego,USA ProgramCommittee AlexBiryukov...WeizmannInstituteofScience,Israel DanBoneh...StanfordUniversity,USA ChristianCachin...IBMResearch,Switzerland RanCanetti...IBMResearch,USA RonaldCramer...ETHZurich,Switzerland YairFrankel...CertCo,USA ShaiHalevi...IBMResearch,USA ArjenLenstra...Citibank,USA MitsuruMatsui...MitsubishiElectricCorporation,Japan PaulVanOorschot...EntrustTechnologies,Canada BartPreneel...KatholiekeUniversiteitLeuven,Belgium PhillipRogaway. ..UniversityofCalifornia,Davis,USA VictorShoup...IBMZurich,Switzerland JessicaStaddon...BellLabsResearch,PaloAlto,USA JacquesStern...EcoleNormaleSup'erieure,France DougStinson...UniversityofWaterloo,Canada SalilVadhan...MassachusettsInstituteofTechnology,USA DavidWagner...UniversityofCalifornia,Berkeley,USA RebeccaWright...AT&TLaboratoriesResearch,USA Advisorymembers MichaelWiener(Crypto1999programchair). . EntrustTechnologies,Canada JoeKilian(Crypto2001programchair)...Intermemory,USA VIII Organization Sub-Referees BillAiello,JeeheaAn,OlivierBaudron,DonBeaver,JoshBenaloh,JohnBlack, SimonBlackburn,AlexandraBoldyreva,NikitaBorisov,VictorBoyko,Jan- menisch,SureshChari,ScottContini,DonCoppersmith,ClaudeCr'epeau,Ivan Damg?ard,AnandDesai,GiovanniDiCrescenzo,YevgeniyDodis,Matthias Fitzi,MattFranklin,RosarioGennaro,GuangGong,LuisGranboulan,Nick Howgrave-Graham,RussellImpagliazzo,YuvalIshai,MarkusJakobsson,Stas Jarecki,ThomasJohansson,CharanjitJutla,JoeKilian,EyalKushilevitz,Moses Liskov,StefanLucks,AnnaLysyanskaya,PhilipMacKenzie,SubhamoyMaitra, TalMalkin,BarbaraMasucci,AlfredMenezes,DanieleMicciancio,SaraMiner, IliaMironov,MoniNaor,PhongNguyen,RafailOstrovsky,ErezPetrank,Birgit P?tzmann,BennyPinkas,DavidPointcheval,GuillaumePoupard,TalRabin, CharlieRacko? ,Zul?karRamzan,OmerReingold,LeoReyzin,PankajRohatgi, AmitSahai,LouisSalvail,ClausSchnorr,MikeSemanko,BobSilverman,Joe Silverman,DanSimon,NigelSmart,BenSmeets,AdamSmith,MartinStrauss, GaneshSundaram,SergeVaudenay,FrederikVercauteren,BernhardvonSt- gel,RuizhongWei,SusanneGudrunWetzel,ColinWilliams,StefanWolf,Felix Wu,YiqunLisaYin,AmirYoussef,RobertZuccherato TableofContents XTRandNTRU TheXTRPublicKeySystem...1 ArjenK. Lenstra,EricR. Verheul AChosen-CiphertextAttackagainstNTRU...20 ' ElianeJaulmes,AntoineJoux PrivacyforDatabases PrivacyPreservingDataMining ...36 YehudaLindell,BennyPinkas ReducingtheServersComputationinPrivateInformationRetrieval: PIRwithPreprocessing...55 AmosBeimel,YuvalIshai,TalMalkin SecureDistributedComputationandApplications ParallelReducibilityforInformation-TheoreticallySecureComputation...74 YevgeniyDodis,SilvioMicali OptimisticFairSecureComputation...93 ChristianCachin,JanCamenisch ACryptographicSolutiontoaGameTheoreticProblem...112 YevgeniyDodis,ShaiHalevi,TalRabin AlgebraicCryptosystems Di?erentialFaultAttacksonEllipticCurveCryptosystems...131 IngridBiehl,BerndMeyer,VolkerMul ..ler QuantumPublic-KeyCryptosystems ...1 47 TatsuakiOkamoto,KeisukeTanaka,ShigenoriUchiyama NewPublic-KeyCryptosystemUsingBraidGroups ...166 KiHyoungKo,SangJinLee,JungHeeCheon,JaeWooHan, Ju-sungKang,ChoonsikPark MessageAuthentication KeyRecoveryandForgeryAttacksontheMacDESMACAlgorithm ...184 DonCoppersmith,LarsR. Knudsen,ChrisJ. Mitchell X TableofContents CBCMACsforArbitrary-LengthMessages:TheThree-KeyConstructions 197 JohnBlack,PhillipRogaway L-collisionAttacksagainstRandomizedMACs...216 MichaelSemanko DigitalSignatures OntheExactSecurityofFullDomainHash...229 Jean-S' ebastienCoron TimedCommitments...236 DanBoneh,MoniNaor APracticalandProvably SecureCoalition-ResistantGroupSignatureScheme...255 GiuseppeAteniese,JanCamenisch,MarcJoye,GeneTsudik ProvablySecurePartiallyBlindSignatures...271 MasayukiAbe,TatsuakiOkamoto Cryptanalysis n WeaknessesintheSL (IF )HashingScheme...287 2 2 RainerSteinwandt,MarkusGrassl,WilliGeiselmann,ThomasBeth FastCorrelationAttacksthroughReconstructionofLinearPolynomials . . 300 ThomasJohansson,FredrikJ.. onsson TraitorTracingandBroadcastEncryption SequentialTraitorTracing...

This book constitutes the refereed proceedings of the Second International Conference in Cryptology in India, INDOCRYPT 2001, held in Chennai, India in December 2001. The 31 revised full papers presented together with an invited survey were carefully reviewed and selected from 77 submissions. The papers are organized in topical sections on hashing, algebraic schemes, elliptic curves, coding theory, applications, cryptanalysis, distributed cryptography, Boolean functions, digitial signatures, and shift registers.

Some years ago, businesses could choose whether to migrate to electronic commerce, however, today it seems they have no choice. Predictions indicate that companies that do not make the necessary changes will be overrun by competition and ultimately fail. Therefore, we see more and more companies undergoing tremendous transformationin order to adapt to the new business paradigm. At the same time new companies are being established. One thing these companies have in common is the increased dependency on security technology. The invention of electronic commerce has changed the role of - curity technologies from being merely a protector to being also an enabler of electronic commerce, and it is clear that the development of security techn- ogy is a key enabler in the growth and deployment of electronic commerce. This has been recognised at European level (European Union 1997e). The launch of a comprehensive EU policy in the area of security in open networksisfairlyrecentwiththeadoptionofaCommunicationoncryptog- phy inOctober 1997(EuropeanUnion1997c). A veryimportantcomplement and support to the European policy is the European Commission s contri- tion to overcometechnological barriers by giving special importance to R&D (Research and Development) activities. The SEMPER project was launched in September 1995 and was funded partly by the European Community within the Advanced Communication Technologies and Services (ACTS) speci?c research programme part of the Fourth Framework Program (1994-1998). In this book the SEMPER project team presents in a coherent, integrated, and readable form the issues - dressed, themotivationfortheworkcarriedout, andthekeyresultsobtained. SEMPER is an innovative project in several aspects."

Security is a rapidly growing area of computer science, with direct and increasing relevance to real life applications such as Internet transactions, electronic commerce, information protection, network and systems integrity, etc. This volume presents thoroughly revised versions of lectures given by leading security researchers during the IFIP WG 1.7 International School on Foundations of Security Analysis and Design, FOSAD 2000, held in Bertinoro, Italy in September. Mathematical Models of Computer Security (Peter Y.A. Ryan); The Logic of Authentication Protocols (Paul Syversen and Iliano Cervesato); Access Control: Policies, Models, and Mechanisms (Pierangela Samarati and Sabrina de Capitani di Vimercati); Security Goals: Packet Trajectories and Strand Spaces (Joshua D. Guttman); Notes on Nominal Calculi for Security and Mobility (Andrew D. Gordon); Classification of Security Properties (Riccardo Focardi and Roberto Gorrieri).

This book constitutes the refereed proceedings of the Third International Conference on Information and Communications Security, ICICS 2001, held in Xian, China in November 2001.The 56 revised full papers presented were carefully reviewed and selected from a total of 134 submissions. The complete spectrum of information and communications security is covered including theoretical foundations, secret sharing, network security, authentication and identification, Boolean functions and stream ciphers, security evaluation, digital signatures, block ciphers and public-key systems, information hiding, security protocols, and cryptanalysis.

This book constitutes the refereed proceedings of the 20th International Conference on Computer Safety, Reliability, and Security, SAFECOMP 2001, held in Budapest, Hungary, in September 2001.The 20 revised full papers presented together with three invited papers were carefully reviewed and selected. The book offers topical sections on reliability assessment and security, safety case and safety analysis, medical systems, human-machine interface, COTS - components off the shelf, testing, formal methods, and control systems.

This book constitutes the refereed proceedings of the Cryptographers' Track at RSA Conference 2001, CT-RSA 2001, in San Francisco, CA, USA in April 2001.The 33 revised full papers presented were carefully reviewed and selected from 65 submissions. The papers are organized in topical sections on new cryptosystems; RSA; symmetric cryptography; gambling and lotteries; reductions, constructions, and security proofs; flaws and attacks; implementation; multivariate cryptography; number theoretic problems; passwords and credentials; and protocols.

This book constitutes the thoroughly refereed post-proceedings of the Second International Workshop on Cryptographic Hardware and Embedded Systems, CHES 2000, held in Worcester, MA, USA in August 2000. The 25 revised full papers presented together with two invited contributions were carefully reviewed and selected from 51 submissions. The papers are organized in topical sections on implementation of elliptic curve cryptosystems, power and timing analysis attacks, hardware implementation of block ciphers, hardware architectures, power analysis attacks, arithmetic architectures, physical security and cryptanalysis, and new schemes and algorithms.

This book constitutes the refereed proceedings of the Fourth International Workshop on Recent Advances in Intrusion Detection, RAID 2001, held in Davis, CA, USA, in October 2001.The 12 revised full papers presented were carefully reviewed and selected from a total of 55 submissions. The papers are organized in sections on logging, cooperation, anomaly detection, intrusion tolerance, legal aspects and specification-based IDS.

Although a vast literature exists on the subject of RSA and public-key cryptography, until now there has been no single source that reveals recent developments in the area at an accessible level. Acclaimed author Richard A. Mollin brings together all of the relevant information available on public-key cryptography (PKC), from RSA to the latest applications of PKC, including electronic cash, secret broadcasting, secret balloting systems, various banking and payment protocols, high security logins, smart cards, and biometrics. Moreover, he covers public-key infrastructure (PKI) and its various security applications.

Throughout the book, Mollin gives a human face to cryptography by including nearly 40 biographies of the individuals who helped develop cryptographic concepts. He includes a number of illustrative and motivating examples, as well as optional topics that go beyond the basics, such as Lenstra's elliptic curve method and the number field sieve. From history and basic concepts to future trends and emerging applications, this book provides a rigorous and detailed treatment of public-key cryptography. Accessible to anyone from the senior undergraduate to the research scientist, RSA and Public-Key Cryptography offers challenging and inspirational material for all readers.

Prepare for test success with this all-in-one CASP+ Certification Kit! The kit includes: CASP+ Study Guide: Exam CAS-004, Fourth Edition, builds on the popular Sybex Study Guide approach, providing 100% coverage of the CASP+ Exam CAS-004 objectives. The book contains clear and concise information on crucial security topics. It includes practical examples and insights drawn from real-world experience, as well as exam highlights and end-of-chapter review questions. The comprehensive study resource provides authoritative coverage of key exam topics, including: Security Architecture Security Operations Security Engineering and Cryptography Governance, Risk, and Compliance Because the exam focuses on practical applications of key security concepts, the book includes an appendix of additional hands-on labs. CASP+ Practice Tests: Exam CAS-004, Second Edition, provides hundreds of domain-by domain questions, covering the CASP+ objectives, PLUS two additional practice exams, for a total of 1,000 practice test questions. You'll also get one year of FREE access after activation to the Sybex interactive learning environment and online test bank. Let this book help you gain the confidence you need for taking the CASP+ Exam CAS-004 and prepare you for test success.

This book constitutes the thoroughly refereed post-proceedings of the Third International Workshop on Cryptoanalysis Hardware and Embedded Systems, CHES 2001, held in Paris, France in Mai 2001. The 31 revised full papers presented were carefully reviewed and selected from 66 submissions. The papers are organized in topical sections on side channel attacks, Rijndael hardware implementation, random number generators, elliptic curve algorithms, arithmetic architectures, cryptanalysis, embedded implementations of ciphers, and side channel attacks on elliptic curve cryptosystems.

This book constitutes the thoroughly refereed post-proceedings of the International Conference on Cryptography and Lattices, CaLC 2001, held in Providence, RI, USA in March 2001. The 14 revised full papers presented together with an overview paper were carefully reviewed and selected for inclusion in the book. All current aspects of lattices and lattice reduction in cryptography, both for cryptographic construction and cryptographic analysis, are addressed.

ASIACRYPT 2000 was the sixth annual ASIACRYPT conference. It was sp- sored by the International Association for Cryptologic Research (IACR) in - operation with the Institute of Electronics, Information, and Communication Engineers (IEICE). The ?rst conference with the name ASIACRYPT took place in 1991, and the series of ASIACRYPT conferences were held in 1994, 1996, 1998, and 1999, in cooperation with IACR. ASIACRYPT 2000 was the ?rst conference in the series to be sponsored by IACR. The conference received 140 submissions (1 submission was withdrawn by the authors later), and the program committee selected 45 of these for presen- tion. Extended abstracts of the revised versions of these papers are included in these proceedings. The program also included two invited lectures by Thomas Berson (Cryptography Everywhere: IACR Distinguished Lecture) and Hideki Imai (CRYPTREC Project - Cryptographic Evaluation Project for the Japanese Electronic Government). Abstracts of these talks are included in these proce- ings. The conference program also included its traditional "rump session" of short, informal or impromptu presentations, kindly chaired by Moti Yung. Those p- sentations are not re?ected in these proceedings. The selection of the program was a challenging task as many high quality submissions were received. The program committee worked very hard to evaluate the papers with respect to quality, originality, and relevance to cryptography. I am extremely grateful to the program committee members for their en- mous investment of time and e?ort in the di?cult and delicate process of review and selection.

This book constitutes the thoroughly refereed post-workshop proceedings of the Third International Workshop on Information Hiding, IH'99, held in Dresden, Germany, in September/October 1999.The 33 revised full papers presented were carefully reviewed and selected from a total of 68 submissions. The dominating topic, dealt with in various contexts, is watermarking. The papers are organized in sections on fundamentals of steganography, paradigms and examples, beyond symmetric steganography; watermarking: proving ownership, detection and decoding, embedding techniques, new designs and applications, improving robustness, software protection; separating private and public information; and stego-engineering.

ThePKC2000conferencewasheldattheMelbourneExhibitionCentre, Victoria, Australia, January 18-20, 2000. It was the third conference in the international workshop series dedicated to practice and theory in public key cryptography. The program committee of the conference received 70 full submissions from around the world, of which 31 were selected for presentation. All submissions were reviewed by experts in the relevant areas. The program committee consisted of 19 experts in cryptography and data se- rity drawn from the international research community, these being Chin-Chen Chang (National Chung Cheng University, Taiwan), Claude Cr epeau (McGill University, Canada), Ed Dawson (Queensland University of Technology, A- tralia), Yvo Desmedt (Florida State University, USA), Hideki Imai (Co-chair, UniversityofTokyo, Japan), MarkusJakobsson(BellLabs, USA), KwangjoKim (Information and Communications University, Korea), Arjen Lenstra (Citibank, USA), TsutomuMatsumoto(YokohamaNationalUniversity, Japan), DavidN- cache (Gemplus, France), Eiji Okamoto (University of Wisconsin-Milwaukee, USA), TatsuakiOkamoto(NTTLabs, Japan), JosefPieprzyk(UniversityofW- longong, Australia), Jean-Jacques Quisquater (Universit e Catholique de L- vain, Belgium), Nigel Smart (HP Labs Bristol, UK), Vijay Varadharajan (U- versity of Western Sydney, Australia), Serge Vaudenay (Ecole Polytechnique F ed erale de Lausanne, Switzerland), Moti Yung (CertCo, USA), and Yuliang Zheng (Co-chair, Monash University, Australia). Members of the committee spent numerous hours in reviewing the submissions and providing advice and comments on the selection of paper

This book presents the refereed proceedings of the International Workshop on Mathematical Methods, Models, and Architectures for Network Security Systems, MMM-ACNS 2001, held in St. Petersburg in May 2001.The 24 revised full papers presented together with five invited contributions were carefully reviewed and selected from 36 submissions. The papers are organized in topical sections on network security systems: foundations, models and architectures; intrusion detection: foundations and models; access control, authentication, and authorization; and cryptography and steganography: mathematical basis, protocols, and applied methods.

Leading researchers in the field of coding theory and cryptography present their newest findings, published here for the first time following a presentation at the International Conference on Coding Theory, Cryptography and Related Areas. The authors include Tom Hoeholdt, Henning Stichtenoth, and Horacio Tapia-Recillas.

Since 1998, RAID has established its reputation as the main event in research on intrusion detection, both in Europe and the United States. Every year, RAID gathers researchers, security vendors and security practitioners to listen to the most recent research results in the area as well as experiments and deployment issues. This year, RAID has grown one step further to establish itself as a well-known event in the security community, with the publication of hardcopy proceedings. RAID 2000 received 26 paper submissions from 10 countries and 3 continents. The program committee selected 14 papers for publication and examined 6 of them for presentation. In addition RAID 2000 received 30 extended abstracts proposals; 15 of these extended abstracts were accepted for presentation. - tended abstracts are available on the website of the RAID symposium series, http: //www.raid-symposium.org/. We would like to thank the technical p- gram committee for the help we received in reviewing the papers, as well as all the authors for their participation and submissions, even for those rejected. As in previous RAID symposiums, the program alternates between fun- mental research issues, such as newtechnologies for intrusion detection, and more practical issues linked to the deployment and operation of intrusion det- tion systems in a real environment. Five sessions have been devoted to intrusion detection technology, including modeling, data mining and advanced techniques

This book constitutes the refereed proceedings of the First International Workshop on Cryptographic Hardware and Embedded Systems, CHES'99, held in Worcester, MA, USA in August 1999. The 27 revised papers presented together with three invited contributions were carefully reviewed and selected from 42 submissions. The papers are organized in sections on cryptographic hardware, hardware architectures, smartcards and embedded systems, arithmetic algorithms, power attacks, true random numbers, cryptographic algorithms on FPGAs, elliptic curve implementations, new cryptographic schemes and modes of operation.

This book constitutes the refereed proceedings of the International Conference on the Theory and Application of Cryptographic Techniques, EUROCRYPT 2000, held in Bruges, Belgium, in May 2000. The 39 revised full papers presented were carefully selected from a total of 150 submissions during a highly competitive reviewing process. The book is divided in topical sections of factoring and discrete logarithm, digital signatures, private information retrieval, key management protocols, threshold cryptography, public-key encryption, quantum cryptography, multi-party computation and information theory, zero-knowledge, symmetric cryptography, Boolean functions and hardware, voting schemes, and stream ciphers and block ciphers.

ICICS 99, the Second International Conference on Information and C- munication Security, was held in Sydney, Australia, 9-11 November 1999. The conference was sponsored by the Distributed System and Network Security - search Unit, University of Western Sydney, Nepean, the Australian Computer Society, IEEE Computer Chapter (NSW), and Harvey World Travel. I am g- teful to all these organizations for their support of the conference. The conference brought together researchers, designers, implementors and users of information security systems and technologies. A range of aspects was addressed from security theory and modeling to system and protocol designs and implementations to applications and management. The conference con- sted of a series of refereed technical papers and invited technical presentations. The program committee invited two distinguished key note speakers. The ?rst keynote speech by Doug McGowan, a Senior Manager from Hewlett-Packard, USA, discussed cryptography in an international setting. Doug described the current status of international cryptography and explored possible future trends and new technologies. The second keynote speech was delivered by Sushil Ja- dia of George Mason University, USA. Sushil s talk addressed the protection of critical information systems. He discussed issues and methods for survivability of systems under malicious attacks and proposed a fault-tolerance based - proach. The conference also hosted a panel on the currently much debated topic of Internet censorship. The panel addressed the issue of censorship from various viewpoints namely legal, industrial, governmental and technical."

This book constitutes the refereed proceedings of the 4th International Workshop on Practice and Theory in Public Key Cryptography, PKC 2001, held in Cheju Island, Korea in February 2001.The 30 revised full papers presented were carefully reviewed and selected from 67 submissions. The papers address all current issues in public key cryptography, ranging from mathematical foundations to implementation issues.

This book constitutes the refereed proceedings of the 4th International Algorithmic Number Theory Symposium, ANTS-IV, held in Leiden, The Netherlands, in July 2000.The book presents 36 contributed papers which have gone through a thorough round of reviewing, selection and revision. Also included are 4 invited survey papers. Among the topics addressed are gcd algorithms, primality, factoring, sieve methods, cryptography, linear algebra, lattices, algebraic number fields, class groups and fields, elliptic curves, polynomials, function fields, and power sums.

The third Financial Cryptography conference was held in February 1999, once again at Anguilla in the British West Indies. The number of attendees continues to increase from year to year, as do the number and quality of the technical submissions. The Program Committee did a great job selecting the technical program. I thank them for all of their eo rt's. We were helped by a number of outside reviewers, including Mart n Abadi, Gerrit Bleumer, Drew Dean, Anand Desai, Mariusz Jakubowski, Andrew Odlyzko, David Pointcheval, Guillaume Poupard, Zul kar Ramzan, Aleta Ricciardi, Dan Simon, Jessica Staddon, Venkie Venka- san, Avishai Wool, and Francis Zane. I apologize for any omissions. Adi Shamir gave an excellent invited talk that forecast the future of crypt- raphy and electronic commerce. On-line certic ate revocation was the subject of a panel led by Michael Myers, following up on the success of his panel on the same topic at last year's conference. Joan Feigenbaum moderated a lively panel on fair use, intellectual property, and the information economy, and I thank her for pulling together from that discussion a paper for these proceedings. A s- cessful Rump Session allowed participants to present new results in an informal setting, superbly chaired by Avi Rubin.