The Turing Award is basically the Nobel Prize of computer science. Today, Cryptography Pioneers Receive ACM A.M. Turing Award "ACM, the Association for Computing Machinery, today named Whitfield Diffie, former Chief Security Officer of Sun Microsystems and Martin E. Hellman, Professor Emeritus of Electrical Engineering at Stanford University, recipients of the 2015 ACM A.M. Turing Award for critical contributions to modern cryptography. The ability for two parties to communicate privately over a secure channel is fundamental for billions of people around the world. On a daily basis, individuals establish secure online connections with banks, e-commerce sites, email servers and the cloud. Diffie and Hellman's groundbreaking 1976 paper, 'New Directions in Cryptography,' introduced the ideas of public-key cryptography and digital signatures, which are the foundation for most regularly-used security protocols on the Internet today. The Diffie-Hellman Protocol protects daily Internet communications and trillions of dollars in financial transactions."
Here's a nice video explanation of their invention: