Whitfield Diffie
lorecryptographysecurity
Co-author, with Martin Hellman, of the 1976 paper New Directions in Cryptography, which proposed public-key cryptography and digital signatures; joint recipient of the 2015 Turing Award.
Before that paper, encryption assumed the two parties had already met, or that a courier had. The paper's move was to separate the key that locks from the key that unlocks, which makes it possible to communicate privately with a stranger - the requirement every subsequent commerce protocol rests on. It described the idea without a practical construction; three people at MIT supplied one the following year. He later spent decades arguing the policy side in public, testifying to both houses of the US Congress on cryptography.
Also known as: diffie