On June 5th, 1991, a puzzling announcement appeared on an online network of political activists known as Peacenet. The announcement was a kind of paradox: a public message that contained instructions for keeping other messages secret. A few hours later, the same note appeared in one of the newsgroups of the global bulletin board USENET. The message volunteered a new standard for encrypting data, based on a scheme known as “public key encryption” that had up to that point mostly been deployed by giant corporations or government agencies. This new standard was designed for the rest of us, and its creator—an anti-nuclear activist and programmer named Phil Zimmermann—was offering it up to the world for free. Zimmermann had given it a memorable if somewhat unassuming name, a play on a grocery store called Ralph’s Pretty Good Groceries featured in one of his favorite public radio shows, A Prairie Home Companion. He called it Pretty Good Privacy, or PGP for short.
But then matters took a surprising turn. Zimmermann’s actions would spark one of the most contentious political fights of early Internet culture, leading to groundbreaking legal decisions that still shape the way we communicate more than 30 years later. Zimmermann would soon find himself the subject of a federal investigation, facing potential jail time. And the most unlikely twist of all was this: the FBI was accusing this longtime peace activist of being an illicit arms dealer.