TCC 2005, the 2nd Annual Theory of Cryptography Conference, was held in Cambridge, Massachusetts, onFebruary10-12,2005.Theconferencereceived84 submissions, ofwhichtheprogramcommitteeselected32forpresentation.These proceedings contain the revised versions of the 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 also included a panel discussion on the future of theoretical cryptography and its relationship to the real world (whatever that is). It also included the traditional "rump session," featuring short, informal talks on late-breaking research news. Much as hatters of old faced mercury-induced neurological damage as an occupational hazard, computer scientists will on rare occasion be a?icted with egocentrism, probably due to prolonged CRT exposure. Thus, you must view withpityandnotcontemptmyunalloyedelationathavingmynameonthefront cover of this LNCS volume, and my deep-seated conviction that I fully deserve the fame and riches that will surely come of it. However, having in recent years switched over to an LCD monitor, I would like to acknowledge some of the many who contributed to this conference. First thanks are due to the many researchers from all over the world who submitted their work to this conference. Lacking shrimp and chocolate-covered strawberries, TCC has to work hard to be a good conference. As a community, I think we have.

This book constitutes the refereed proceedings of the 21st Annual International Cryptology Conference, CRYPTO 2001, held in Santa Barbara, CA, USA in August 2001. The 33 revised full papers presented were carefully reviewed and selected from a total of 156 submissions. The papers are organized in topical sections on foundations, traitor tracing, multi-party computation, two-party computation, elliptic curves, OAEP, encryption and authentication, signature schemes, protocols, cryptanalysis, applications of group theory and coding theory, broadcast and secret sharing, and soundness and zero-knowledge.