This book constitutes the refereed proceedings of the 5th International Conference on Cryptology and Network Security, CANS 2006, held in Suzhou, China in December 2006.

The 26 revised full papers presented together with 2 invited papers were carefully reviewed and selected from 148 submissions. The papers are organized in topical sections on encryption, key exchange, authentication and signatures, proxy signatures, cryptanalysis, implementation, steganalysis and watermarking, boolean functions and stream ciphers, intrusion detection, as well as disponibility and reliability.