Clifford Christopher Cocks CB FRS (born 28 December 1950) is a British mathematician and cryptographer.In 1973, while working at the United Kingdom Government Communications Headquarters (GCHQ), he invented a public key cryptography algorithm equivalent to what would become (in 1978) the RSA algorithm. The idea was classified information and his insight remained hidden for 24 years, despite being independently invented by Rivest, Shamir, and Adleman in 1977. Public-key cryptography using prime factorisation is now part of nearly every Internet transaction.