Simon (cipher)

Simon
One round of Simon
General
DesignersRay Beaulieu, Douglas Shors, Jason Smith, Stefan Treatman-Clark, Bryan Weeks, Louis Wingers NSA
First published2013
Related toSpeck
Cipher detail
Key sizes64, 72, 96, 128, 144, 192 or 256 bits
Block sizes32, 48, 64, 96 or 128 bits
StructureBalanced Feistel network
Rounds32, 36, 42, 44, 52, 54, 68, 69 or 72 (depending on block and key size)
Speed7.5 cpb (21.6 without SSE) on Intel Xeon 5640 (Simon128/128)
Best public cryptanalysis
Differential cryptanalysis can break 46 rounds of Simon128/128 with 2125.6 data, 240.6 bytes memory and time complexity of 2125.7 with success rate of 0.632.

Simon is a family of lightweight block ciphers publicly released by the National Security Agency (NSA) in June 2013. Simon has been optimized for performance in hardware implementations, while its sister algorithm, Speck, has been optimized for software implementations.

The NSA began working on the Simon and Speck ciphers in 2011. The agency anticipated some agencies in the US federal government would need a cipher that would operate well on a diverse collection of Internet of Things devices while maintaining an acceptable level of security.