Cryptography as information control

In 1976, two researchers declared a revolution in cryptography: With the invention of public key encryption, cryptography could be used not only to share secret messages, but to secure and authenticate communications networks, and, eventually, to enable radically new kinds of social relationships facilitated by networked communication technology. This article explores a series of transformations in the meaning of cryptography in the 1960s and 1970s that led to the declaration of a revolution. Drawing on archival materials, the article considers how public key cryptography was the product of an emerging consensus among cryptographers of the importance of privacy in the wake of abuses of surveillance powers by government agencies. Shaped by a changing technological and political environment, it situates cryptography at the center of a focused effort to assert control over information in an era of sociopolitical upheaval, concluding that the invention of public key encryption both marked a change in the imaginary surrounding cryptography and offered a technical solution that foreclosed other approaches to addressing the problem of surveillance.