Martin E. Hellman is Professor Emeritus of Electrical Engineering at Stanford University. His own Stanford home page identifies him as a co-inventor of public-key cryptography, the technology he describes as enabling secure Internet transactions that process trillions of dollars every day.
In 1976, with Whitfield Diffie, Hellman published “New Directions in Cryptography” in the IEEE Transactions on Information Theory. The paper, hosted on his Stanford publications page, introduced public-key cryptography, a method for two parties to agree on a shared key over a public channel, and the idea of digital signatures. His page also credits Ralph Merkle as a contributor to the invention of public-key cryptography.
Hellman’s pages recount his role in what he calls the first crypto war of the late 1970s and 1980s, when he defended the right of academic researchers to publish cryptographic work without government censorship. This made him a public figure in the long debate over civilian access to strong cryptography.
His Stanford home page notes that he received the million-dollar ACM Turing Award, often called the Nobel Prize of Computer Science. In later years his attention turned to reducing nuclear risk, reflected in his work “Defusing the Nuclear Threat” and his focus on rethinking national security and the ethics of technological development.