In August 1960 the Pentagon announced that William Martin and Bernon Mitchell had not returned from vacation and said “there is a likelihood that they have gone behind the Iron Curtain”. On September 6 they appeared at a joint news conference at the House of Journalists in Moscow and announced they had requested asylum and Soviet citizenship. They revealed that they had worked for the National Security Agency (NSA). In this way the mission and activities of the NSA were made public for the first time . Although these activities are much more wide-ranging than cryptology, this post will only be concerned with that small part.
All branches of knowledge had vigorously developed in the first half of the 20th century. All of it had been sustained by what I like to call a conversation: an open exchange of knowledge in books and journals. Before World War I this was also true for cryptology; afterwards, traffic on that channel fell silent. By the end of the 20th century the cryptology conversation was intense, wide-ranging, and immensely productive of innovations, of which bitcoin technology is but one example. In this post I trace the chain of events that led cryptology from its dark age, which lasted from 1918 to 1967, to its renaissance. My material is obtained, unless otherwise noted, from Crypto, a book by Steven Levy, published in 2001 .