The encyclopedia · Software & IT · Product decision · 1991–1996
PGP beat US export rules by publishing its source code as a printed book
Phil Zimmermann gave PGP away free and printed the source code in a book, turning crypto export into protected speech.
Phil Zimmermann
the move
In 1991 Phil Zimmermann wrote PGP, a program that let ordinary people encrypt email with public-key cryptography, and posted it on the Internet for free. The US government treated strong encryption as a munition, and exporting the software without a license could be a crime.
Zimmermann's answer was to publish the complete PGP source code as a hardback book through MIT Press in 1995. Books were protected speech under the First Amendment, so the code crossed borders as literature; readers could type it in or scan it back into software.
The stunt reframed the debate and the code spread worldwide. The federal investigation into Zimmermann was closed without charges in 1996, encryption export rules were later relaxed, and PGP's message format became the OpenPGP standard implemented by GnuPG and dozens of other tools.
why it works
- Public-key crypto let strangers exchange secrets without sharing keys
- Free distribution built a global user base no vendor could match
- A printed book was exportable speech, not a munition
- The format outlived the company because it became an open standard
what transfers
When a rule blocks the obvious channel, find the one the rule was never designed to close — and give the product away so adoption does the marketing.
what came after
After the investigation closed, Zimmermann's team founded PGP Inc., and the OpenPGP message format was standardized as RFC 4880 in 2007, still the basis of most email encryption. The crypto-is-speech argument also shaped later legal fights over encryption and export controls.
references
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