Diffie and Martin Hellman's paper "New Directions in Cryptography" published in 1976. 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. The article also seems to have stimulated the almost immediate public development of a new class of encryption algorithms, the asymmetric key algorithms, which enable public key encryption.
After a long career at Sun Microsystems, where he became a Sun Fellow, Diffie is currently serving as the Vice President for Information Security and Cryptography at the Internet Corporation for Assigned Names and Numbers (ICANN) and a visiting scholar at the Freeman Spogli Institute's Center for International Security and Cooperation at Stanford University. He also serves as Chief Cryptographer for Revere Security.
[Adapted from the Whitfield Diffie Wikipedia entry.