EUROCRYEVr '97, the 15th annual EUROCRYPT conference on the theory and application of cryptographic techniques, was organized and sponsored by the International Association for Cryptologic Research (IACR). The IACR organizes two series of international conferences each year, the EUROCRYPT meeting in Europe and CRWTO in the United States. The history of EUROCRYFT started 15 years ago in Germany with the Burg Feuerstein Workshop (see Springer LNCS 149 for the proceedings). It was due to Thomas Beth's initiative and hard work that the 76 participants from 14 countries gathered in Burg Feuerstein for the first open meeting in Europe devoted to modem cryptography. I am proud to have been one of the participants and still fondly remember my first encounters with some of the celebrities in cryptography. Since those early days the conference has been held in a different location in Europe each year (Udine, Paris, Linz, Linkoping, Amsterdam, Davos, Houthalen, Aarhus, Brighton, Balantonfiired, Lofthus, Perugia, Saint-Malo, Saragossa) and it has enjoyed a steady growth, Since the second conference (Udine, 1983) the IACR has been involved, since the Paris meeting in 1984, the name EUROCRYPT has been used. For its 15th anniversary, EUROCRYPT finally returned to Germany. The scientific program for EUROCRYPT '97 was put together by a 18-member program committee whch considered 104 high-quality submissions. These proceedings contain the revised versions of the 34 papers that were accepted for presentation. In addition, there were two invited talks by Ernst Bovelander and by Gerhard Frey.

This book constitutes the refereed proceedings of the 17th Annual International Cryptology Conference, CRYPTO'97, held in Santa Barbara, California, USA, in August 1997 under the sponsorship of the International Association for Cryptologic Research (IACR). The volume presents 35 revised full papers selected from 160 submissions received. Also included are two invited presentations. The papers are organized in sections on complexity theory, cryptographic primitives, lattice-based cryptography, digital signatures, cryptanalysis of public-key cryptosystems, information theory, elliptic curve implementation, number-theoretic systems, distributed cryptography, hash functions, cryptanalysis of secret-key cryptosystems.

The objective of this paper is to discuss the Theory and Application of Cryptographic Techniques used to develop crypt analytic attacks on A5 that can reconstruct the 64-bit secret key in the known plain text scenario with the computational complexity smaller than 264.

AboutCryptology It is nowwidelyperceivedthatweareexperiencinganinformationrevolution whose e?ects will ultimately be as pervasive and profound as was brought by the industrial revolution of the last century. From the beginning of time, information has been an important asset for humans. In the early days of humanexistence,themereknowledgeofwheretomosteasilygatherfoodwas the di?erence between life and death. Throughout history, information has provided the means for winning wars, making fortunes, and shaping history. The underlying theme of the information revolution is that we continue to ?nd new ways to use information. These new uses for information serve to highlight our need to protect di?erent aspects of information. Cryptology may be broadly de?ned as the scienti?c study of adversarial information protection. Cryptology has traditionally dealt with the co- dentiality of information, but innovation in using information produces new requirements for protection of that information. Some are longstanding and fundamental - how do we guarantee that information is ”authentic”? How do we guarantee that information is timely? How can we produce bits that have the same properties as ”money”? Each of these questions has been grappled with in the cryptologic research community.

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.

This book constitutes the refereed proceedings of the 1998 International Conference on the Theory and Application of Cryptographic Techniques, EUROCRYPT '98, held in Espoo, Finland, in May/June 1998. The book presents 44 revised full papers selected from a total of 161 submissions. The papers are organized in sections on distributed cryptography, complexity, cryptanalysis of block ciphers, computational algorithms, paradigms for symmetric systems, public key cryptosystems, multi-party computation, digital signatures, Boolean functions, combinatorial design and analysis, elliptic curve systems, and electronic commerce and payment.