Clifford Christopher Cocks is a British mathematician and cryptographer at GCHQ who invented the widely-used encryption algorithm now commonly known as RSA, about three years before it was independently developed by Rivest, Shamir, and Adleman at MIT. He has not been generally recognised for this achievement because his work was not released to the public at the time. A mathematician is a person whose area of study and research is mathematics. ... Pre-19th century Leone Battista Alberti, polymath/universal genius, inventor of polyalphabetic substitution (see frequency analysis for the significance of this -- missed by most for a long time and dumbed down in the Vigenère cipher), and what may have been the first mechanical encryption aid. ... The Government Communications Headquarters (GCHQ) (previously named the Government Code and Cipher School (GC&CS)) is the main British intelligence service providing signals intelligence (SIGINT). ... In cryptography, RSA is an algorithm for public key encryption. ... Professor Ron Rivest Professor Ronald Linn Rivest (born 1947, Schenectady, New York) is a cryptographer, and is the Viterbi Professor of Computer Science at MITs Department of Electrical Engineering and Computer Science. ... Adi Shamir at the CRYPTO 2003 conference. ... Leonard Adleman Leonard Adleman (born December 31, 1945) is a theoretical computer scientist and professor of computer science and molecular biology at the University of Southern California. ... The Massachusetts Institute of Technology, or MIT, is a research institution and university located in the city of Cambridge, Massachusetts directly across the Charles River from Bostons Back Bay district. ...

In 1968, Cocks won Silver at the International Mathematical Olympiad while at Manchester Grammar School. Cocks went on to study mathematics as an undergraduate at King's College, Cambridge and then did graduate work at the University of Oxford, where he specialised in number theory, but dropped out to join CESG, an arm of GCHQ, in September 1973. 1968 was a leap year starting on Monday (the link is to a full 1968 calendar). ... The International Mathematical Olympiad (IMO) is an annual contest for high school students. ... The Manchester Grammar School (MGS) is an independent boys school (ages 11-18) in Manchester, England. ... Full name The Kings College of Our Lady and St Nicholas Motto Veritas Et Utilitas Truth and usefulness Named after Henry VI Previous names - Established 1441 Sister College New College Provost Dame Judith Mayhew-Jonas Location Kings Parade Undergraduates 397 Graduates 239 Homepage Boatclub Kings College, Cambridge... The University of Oxford, located in the city of Oxford in England, is the oldest university in the English-speaking world. ... Traditionally, number theory is that branch of pure mathematics concerned with the properties of integers. ... The Government Communications Headquarters (GCHQ) (previously named the Government Code and Cipher School (GC&CS)) is the main British intelligence service providing signals intelligence (SIGINT). ... 1973 was a common year starting on Monday. ...

At GCHQ, Cocks was told about James Ellis' "non-secret encryption" and further that since it had been suggested in the late 1960s, no one had been able to find a way to actually implement the concept. Cocks was intrigued, thought about it overnight, and invented, in 1973, what has become known as the RSA encryption algorithm, realising Ellis' idea. GCHQ appears not to have been able to find a way to use the idea, and in any case, treated it as classified, so that when it was reinvented and published by Rivest, Shamir, and Adleman in 1976, Cocks' prior achievement remained unknown until 1997. James H. Ellis (1924–November 1997) was an engineer and mathematician. ... PKC, see PKC (disambiguation) Public-key cryptography is a form of modern cryptography which allows users to communicate securely without previously agreeing on a shared secret key. ... 1960 was a leap year starting on Friday (link will take you to calendar). ... 1973 was a common year starting on Monday. ... Classified information is secret information to which access is restricted by law or corporate rules to a particular hierarchical class of people. ... 1976 is a leap year starting on Thursday (link will take you to calendar). ... 1997 is a common year starting on Wednesday of the Gregorian calendar. ...

Clifford Cocks currently (2003) holds the post of Chief Mathematician at GCHQ. 2003 is a common year starting on Wednesday of the Gregorian calendar, and also: The International Year of Freshwater The European Disability Year Events January events January 1 Luíz Inácio Lula Da Silva becomes the 37th President of Brazil. ...

External links

• Wired article on public key cryptography at GCHQ (http://www.wired.com/wired/archive/7.04/crypto.html)
• James Ellis' account of the invention of non-secret encryption (http://www.jya.com/ellisdoc.htm)
• Cock's internal GCHQ note on his discovery (http://www.cesg.gov.uk/site/publications/media/notense.pdf)