John Herivel

John Herivel

John W. Herivel (29 August 1918 – 18 January 2011) was a British science historian and former World War II codebreaker at Bletchley Park.

As a codebreaker concerned with Cryptanalysis of the Enigma, Herivel is remembered chiefly for the discovery of what was soon dubbed the Herivel tip or Herivelismus. The "tip" was an insight into the habits of German operators of the Enigma cipher machine that allowed Bletchley Park to easily deduce part of the daily key. For a brief but critical few months from May 1940, the Herivel tip in conjunction with "cillies" (another class of operator error) was the main technique used to solve Enigma.

Herivel wrote books and articles on Isaac Newton, Joseph Fourier, Christiaan Huygens, and an autobiographical account of his work at Bletchley Park, Herivelismus.

Read more about John Herivel:  Recruitment To Bletchley, Operator Error, Exploiting The Tip, After World War II