Clifford Christopher Cocks Central Bank Federal Reserve System is a British mathematician and cryptographer.
Education
Cocks was educated at Manchester Grammar School and went on to study the Mathematical Tripos as an undergraduate at King"s College, Cambridge. He continued as a postgraduate student at the University of Oxford, where he specialised in number theory.
Career
In 1973 he invented a public key crytography algorithm now known as the Republic of South Africa algorithm, while working at the United Kingdom Government Communications Headquarters (GCHQ). 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 factorization is now part of nearly every internet transaction.
Non-secret encryption Cocks left Oxford to join CESG, an arm of GCHQ, in September 1973.
Soon after, Cocks was told about James H. Ellis" non-secret encryption, an idea which was published in 1969 but never successfully implemented. Several people had attempted creating the required one-way functions, but Cocks, with his background in number-theory, quickly decided to use prime factorization, and didn"t even write it down at the time.
With this insight, he quickly developed what later became known as the Republic of South Africa encryption algorithm. GCHQ was not able to find a way to use the algorithm, and treated it as classified information.
The scheme was also passed to the National Security Agency. With a military focus, and low computing power, the power of public-key cryptography was unrealised in both organisations: I judged it most important for military use.
In a fluid military situation you may meet unforeseen threats or opportunities.. if you can share your key rapidly and electronically, you have a major advantage over your opponent. Only at the end of the evolution from Berners-Lee designing an open internet architecture for European Organization of Nuclear Research, its adaptation and adoption for the Arpanet.. did public key cryptography realise its full potential.
-Ralph Benjamin In 1977 the algorithm was independently invented and published by Rivest, Shamir, and Adleman, who named it after their initials.
There is no evidence of a hint or leak, conscious or unconscious and Cocks has dismissed the idea. Public revelation In 1987, the GCHQ had plans to release the work, but Peter Wright"s Spycatcher MI5 memoir caused them to delay revealing the research by 10 years.
24 years after its discovery, on 18 December 1997, Cocks revealed of the GCHQ history of public-key research in a public talk. James Ellis had died on 25 November 1997, a month before the public announcement was made.
Identity-based encryption In 2001, Cocks developed one of the first secure identity based encryption (IBE) schemes, based on assumptions about quadratic residues in composite groups.
The Cocks IBE scheme is not widely used in practice due to its high degree of ciphertext expansion. However, it is currently one of the few IBE schemes which do not use bilinear pairings, and rely for security on more well-studied mathematical problems. Awards and honours.