PGP

The object

PGP — Pretty Good Privacy — is an encryption program written by Phil Zimmermann and released in June 1991. It put military-grade public-key cryptography, previously the domain of governments and banks, into the hands of any individual with a computer.

A crime to publish

At the time, strong cryptography was legally classified by the United States as a munition; exporting it could be prosecuted like trafficking weapons. PGP spread to the global internet anyway, and Zimmermann became the target of a three-year federal criminal investigation. In response, MIT Press published the entire source code as a book — speech, not software, and therefore protected. The case was eventually dropped, and the "crypto wars" turned.

Why it matters

PGP reframed encryption as a civil right rather than a state privilege. It armed journalists, dissidents, and ordinary people with the ability to communicate without permission. The phreaker's question — who is allowed to use this system? — was answered here with mathematics: everyone, by default.

It also extended copyleft's insight. Zimmermann did not just write a tool; he engineered a legal and political event, distributing it in a form the law could not easily stop.

The lesson it set loose

Cryptography is politics expressed as math. A cipher anyone can run shifts the balance of power between individuals and institutions, and no regulation can fully un-publish a number. PGP made privacy something you could do, not merely something you were granted.