This book constitutes the refereed proceedings of the 5th International Conference on Information and Communication Security, ICICS 2003, held in Huhehaote, China, in October 2003. The 37 revised full papers presented were carefully reviewed and selected from 176 submissions. The papers address a broad variety of topics in information and communications security including finite field computations, digital signature schemes, mobile agents security, access control, cryptographic attacks, public key cryptography, peer-to-peer security, watermarking, broadcast encryption, information hiding, cryptographic protocols, oblivious transfer, fingerprinting schemes, security verification, TCP/IP security, support vector machine, intrusion detection, and authenticated encryption schemes.