This book constitutes the refereed proceedings of the Cryptographers' Track at the RSA Conference 2008, CT-RSA 2008, held in San Francisco, CA, USA in April 2008. The 26 revised full papers presented together with the abstract of 1 invited talk were carefully reviewed and selected from 95 submissions. The papers are organized in topical sections on hash function cryptanalysis, cryptographic building blocks, fairness in secure computation, message authentication codes, improved aes implementations, public key encryption with special properties, side channel cryptanalysis, cryptography for limited devices, invited talk, key exchange, cryptanalysis, and cryptographic protocols. The RSA Conference is the largest regularly-staged computer security event, with over 350 vendors and many thousands of attendees. The Cryptographers¿ Track (CT-RSA) is a research conference within the RSA Conference. CT-RSA began in 2001, and has become one of the major established venues for presenting cryptographic research papers to a wide variety of audiences. CT-RSA 2008 was held in San Francisco, California from April 8 to April 11. The proceedings of CT-RSA 2008 contain 26 papers selected from 95 subm- sions pertaining to all aspects of cryptography. Each submission was reviewed by at least three reviewers, which was made possible by the hard work of 27 P- gram Committee members and many external reviewers listed on the following pages. The papers were selected following a detailed online discussion among the Program Committee members. The program included an invited talk by Sha? Goldwasser. The current proceedings include a short abstract of her talk. I would like to express my deep gratitude to the Program Committee m- bers, who volunteered their expertise and hard work over several months, as well as to the external reviewers. Special thanks to Shai Halevi for providing and maintaining the Web review system used for paper submission, reviewing, and ?nal-version preparation. Finally, I would like to thank Burt Kaliski and Ari Juels of RSA Laboratories, as well as the RSA conference team, especially Bree LaBollita, for their assistance throughout the process.