This book constitutes the thoroughly refereed post-conference proceedings of the 10th International Workshop on Information Security Applications, WISA 2009, held in Busan, Korea, during August 25-27, 2009. The 27 revised full papers presented were carefully reviewed and selected from a total of 79 submissions. The papers are organized in topical sections on mutlimedia security, device security, HW implementation security, applied cryptography, side channel attacks, cryptograptanalysis, anonymity/authentication/access controll, and network security.