James H. Ellis

James H. Ellis was a British cryptographer working at the UK’s Government Communications Headquarters (GCHQ). In the late 1960s, Ellis conceived the idea of non-secret encryption — a method that allowed secure communication without first sharing a secret key. Because his work was classified, it remained unknown to the public for years. In the 1970s, the same idea was independently rediscovered and published by Diffie and Hellman in the open academic world, fundamentally reshaping modern cryptography. Ellis never sought recognition and never publicly claimed credit while alive. Only decades later did declassification reveal that the foundations of public-key cryptography had been quietly laid inside a locked room.