This book constitutes the refereed proceedings of the 9th International Conference on the Theory and Application of Cryptology and Information Security, ASIACRYPT 2003, held in Taipei, Taiwan in November/December 2003.The 32 revised full papers presented together with one invited paper were carefully reviewed and selected from 188 submissions. The papers are organized in topical sections on public key cryptography, number theory, efficient implementations, key management and protocols, hash functions, group signatures, block cyphers, broadcast and multicast, foundations and complexity theory,...