This book constitutes the thoroughly refereed post-proceedings of the 14th International Workshop on Selected Areas in Cryptography, SAC 2007, held in Ottawa, Canada, in August 2007. The 25 revised full papers presented were carefully reviewed and selected from 73 submissions. The papers are organized in topical sections on stream cipher cryptanalysis, hash function attacks, side-channel attacks, efficient implementations, block cipher cryptanalysis, a new stream cipher, white box cryptanalysis, message authentication code attack, and modes of operation.