This book constitutes the refereed proceedings of the Second International Conference on Information and Communication Security, ICICS'99, held in Sydney, Australia in November 1999. The 24 revised full papers presented were carefully reviewed and selected from a total of 62 submissions. The book is divided in topical sections on cryptanalysis, language-based approaches to security, electronic commerce and secret sharing, digital signatures, security protocols, applications, cryptography, and complexity and security functions.