Whitfield Diffie and Martin Hellman, researchers at Stanford University, publish in November 1976 "New Directions in Cryptography" in IEEE Transactions on Information Theory, introducing the concept of public-key cryptography into the open scientific literature and the discrete-logarithm key-exchange protocol. The article is the most cited in the history of cryptography. Its open publication launches the field of public-key cryptography in academia and industry. Diffie and Hellman did not know of the classified GCHQ work — Cocks (1973), Ellis (1970), Williamson (1974) — which had solved the same problems three years earlier in secret. They received the Turing Award in 2015.