FSE 2008 is the 15th annual Fast Software Encryption workshop. It is sponsored by the International Association for Cryptologic Research (IACR). Original research papers on symmetric cryptology are invited for submission to FSE 2008. The workshop concentrates on fast and secure primitives for symmetric cryptography, including the design and analysis of block ciphers, stream ciphers, encryption schemes, analysis and evaluation tools, hash functions, and message authentication codes (MACs).