This book constitutes the thoroughly refereed post-workshop proceedings of the 13th International Workshop on Information Security Applications, WISA 2012, held in Jeju Island, Korea, in August 2012. <br>The 26 revised full papers presented together with 8 short papers were carefully reviewed and selected from 100 submissions. The papers are focusing on all technical and practical aspects of symmetric cipher, secure hardware/public key crypto application, cryptographic protocols/digital forensics, network security, and trust management/database security.