This book constitutes the thoroughly refereed post-conference proceedings of the 18th
International Workshop on Fast Software Encryption held in Lyngby Denmark in February 2011.
The 22 revised full papers presented together with 1 invited lecture were carefully reviewed
and selected from 106 initial submissions. The papers are organized in topical sections on
differential cryptanalysis hash functions security and models stream ciphers block ciphers
and modes as well as linear and differential cryptanalysis.
