An Account of the ISO/IEC Standardization of the Simon and Speck Block Cipher Families

AbstractSimon and Speck are two block cipher families published in 2013 by the US National Security Agency (NSA). These block ciphers, targeting lightweight applications, were suggested in 2015 to be included in ISO/IEC 29192-2 Information technology—Security techniques—Lightweight cryptography—Part 2: Block ciphers. Following 3.5 years of deliberations within ISO/IEC JTC 1 they were rejected in April 2018. This chapter provides an account of the ISO/IEC standardization process for Simon and Speck.