This book constitutes the thoroughly refereed post-proceedings of the 6th International Conference on Information Security and Cryptology, ICISC 2003, held in Seoul, Korea, in November 2003. The 32 revised full papers presented together with an invited paper were carefully selected from 163 submissions during two rounds of reviewing and improvement. The papers are organized in topical sections on digital signatures, primitives, fast implementations, computer security and mobile security, voting and auction protocols, watermarking, authentication and threshold protocols, and block ciphers and stream ciphers.