Bailey Whitfield 'Whit' Diffie (born June 5, 1944) is an American cryptographer and one of the pioneers of public-key cryptography.Diffie and Martin Hellman's paper New Directions in Cryptography was published in 1976. It introduced a radically new method of distributing cryptographic keys, that went far toward solving one of the fundamental problems of cryptography, key distribution. It has become known as Diffie–Hellman key exchange.