International Association for Cryptologic Research
SIMON is a family of lightweight block ciphers that was proposed by U.S National Security Agency (NSA). A cipher in this family with K-bit key and N-bit block is called SIMON N=K. In this paper the authors analyze the security of SIMON against linear cryptanalysis. They present several linear characteristics for all variants of SIMON with reduced number of rounds. Their best linear characteristic covers SIMON 32/64 reduced to 13 rounds out of 32 rounds with the bias of 216. In addition, they describe a connection between linear and differential characteristics for SIMON.