This book constitutes the refereed proceedings of the Cryptographers' Track at the RSA Conference 2009, CT-RSA 2009, held in San Francisco, CA, USA in April 2009.The 31 revised full papers presented were carefully reviewed and selected from 93 submissions. The papers are organized in topical sections on identity-based encryption, protocol analysis, two-party protocols, more than signatures, collisions for hash functions, cryptanalysis, alternative encryption, privacy and anonymity, efficiency improvements, multi-party protocols, security of encryption schemes as well as countermeasures and faults.