This book constitutes the refereed proceedings of the 5th International Information Security Practice and Experience Conference, ISPEC 2009, held in Xi'an, China in April 2009. The 34 revised full papers were carefully reviewed and selected from 147 submissions. The papers are organized in topical sections on public key encryption, digital signatures, system security, applied cryptography, multimedia security and DRM, security protocols, key exchange and management, hash functions and MACs, cryptanalysis, network security as well as security applications.