This book constitutes the thoroughly refereed post-conference proceedings of the 22nd International Workshop on Fast Software Encryption, held in Istanbul, Turkey, March 8-11, 2015. The 28 revised full papers presented were carefully reviewed and selected from 71 initial submissions. The papers are organized in topical sections on block cipher cryptanalysis; understanding attacks; implementation issues; more block cipher cryptanalysis; cryptanalysis of authenticated encryption schemes; proofs; design; lightweight; cryptanalysis of hash functions and stream ciphers; and mass surveillance.

This book constitutes the refereed post-conference proceedings of the 4th International Workshop on Lightweight Cryptography for Security and Privacy, LightSec 2015, held in Bochum, Germany, in September 2015. The 9 full papers presented were carefully reviewed and selected from 17 submissions. The papers are organized in the following topical sections: cryptanalysis, lightweight constructions, implementation challenges.