Crypto 2001, the 21st Annual Crypto conference, was sponsored by the Int- national Association for Cryptologic Research (IACR) in cooperation with the IEEE Computer Society Technical Committee on Security and Privacy and the Computer Science Department of the University of California at Santa Barbara. The conference received 156 submissions, of which the program committee selected 34 for presentation; one was later withdrawn. These proceedings contain the revised versions of the 33 submissions that were presented at the conference. These revisions have not been checked for correctness, and the authors bear full responsibility for the contents of their papers. The conference program included two invited lectures. Mark Sherwin spoke on, \Quantum information processing in semiconductors: an experimentalist’s view." Daniel Weitzner spoke on, \Privacy, Authentication & Identity: A recent history of cryptographic struggles for freedom." The conference program also included its perennial \rump session," chaired by Stuart Haber, featuring short, informal talks on late{breaking research news. As I try to account for the hours of my life that ?ew o to oblivion, I realize that most of my time was spent cajoling talented innocents into spending even more time on my behalf. I have accumulated more debts than I can ever hope to repay. As mere statements of thanks are certainly insu cient, consider the rest of this preface my version of Chapter 11.

Crypto 2001, the 21st Annual Crypto conference, was sponsored by the Int- national Association for Cryptologic Research (IACR) in cooperation with the IEEE Computer Society Technical Committee on Security and Privacy and the Computer Science Department of the University of California at Santa Barbara. The conference received 156 submissions, of which the program committee selected 34 for presentation; one was later withdrawn. These proceedings contain the revised versions of the 33 submissions that were presented at the conference. These revisions have not been checked for correctness, and the authors bear full responsibility for the contents of their papers. The conference program included two invited lectures. Mark Sherwin spoke on, \Quantum information processing in semiconductors: an experimentalist’s view." Daniel Weitzner spoke on, \Privacy, Authentication & Identity: A recent history of cryptographic struggles for freedom." The conference program also included its perennial \rump session," chaired by Stuart Haber, featuring short, informal talks on late{breaking research news. As I try to account for the hours of my life that ?ew o to oblivion, I realize that most of my time was spent cajoling talented innocents into spending even more time on my behalf. I have accumulated more debts than I can ever hope to repay. As mere statements of thanks are certainly insu cient, consider the rest of this preface my version of Chapter 11.

The LNCS series reports state-of-the-art results in computer science research, development, and education, at a high level and in both printed and electronic form. Enjoying tight cooperation with the R & D community, with numerous individuals, as well as with prestigious organizations and societies, LNCS has grown into the most comprehensive computer science research forum available. The scope of LNCS, including its subseries LNAI, spans the whole range of computer science and information technology including interdisciplinary topics in a variety of application fields. The type of material published traditionally includes: proceedings (published in time for the respective conference); post-proceedings (consisting of thoroughly revised final full papers); research monographs (which may be based on outstanding PhD); work, research projects, technical reports, etc.)

CRYPTO is a conference devoted to all aspects of cryptologic research. It is held each year at the University of California at Santa Barbara. Annual meetings on this topic also take place in Europe and are regularly published in this Lecture Notes series under the name of EUROCRYPT. This volume presents the proceedings of the ninth CRYPTO meeting. The papers are organized into sections with the following themes: Why is cryptography harder than it looks?, pseudo-randomness and sequences, cryptanalysis and implementation, signature and authentication, threshold schemes and key management, key distribution and network security, fast computation, odds and ends, zero-knowledge and oblivious transfer, multiparty computation.

EUROCRYPT 2001, the 20th annual Eurocrypt conference, was sponsored by the IACR, the International Association for Cryptologic Research, see http://www. iacr. org/, this year in cooperation with the Austrian Computer - ciety (OCG). The General Chair, Reinhard Posch, was responsible for local or- nization, and registration was handled by the IACR Secretariat at the University of California, Santa Barbara. In addition to the papers contained in these proceedings, we were pleased that the conference program also included a presentation by the 2001 IACR d- tinguished lecturer, Andrew Odlyzko, on “Economics and Cryptography” and an invited talk by Silvio Micali, “Zero Knowledge Has Come of Age. ” Furthermore, there was the rump session for presentations of recent results and other (p- sibly satirical) topics of interest to the crypto community, which Jean-Jacques Quisquater kindly agreed to run. The Program Committee received 155 submissions and selected 33 papers for presentation; one of them was withdrawn by the authors. The review process was therefore a delicate and challenging task for the committee members, and I wish to thank them for all the e?ort they spent on it. Each committee member was responsible for the review of at least 20 submissions, so each paper was carefully evaluated by at least three reviewers, and submissions with a program committee member as a (co-)author by at least six.