This book constitutes the refereed proceedings of the First SKLOIS (State Key Laboratory of Information Security) Conference on Information Security and Cryptology, CISC 2005, held in Beijing, China in December 2005. The 33 revised full papers and 32 short papers presented together with 2 invited papers were carefully reviewed and selected from 196 submissions. The papers are organized in topical sections on identity based cryptography, security modelling, systems security, signature schemes, symmetric key mechanisms, zero-knowledge and secure computations, threshold cryptography, intrusion detection systems, protocol cryptanalysis, ECC algorithms, applications, secret sharing, and denial of service attacks.