Phil Zimmermann

Phil Zimmermann became the target of a three-year criminal investigation by U.S. Customs for allegedly exporting munitions without a license. At the time, encryption software like his Pretty Good Privacy (PGP) program was classified as military-grade munitions under U.S. export law. The investigation was ultimately dropped in 1996 without any charges being filed.

Phil Zimmermann is best known as the creator of Pretty Good Privacy (PGP), a revolutionary data encryption and decryption program for secure communication. PGP was initially released in 1991, making military-grade cryptography accessible to the general public for the first time. He later founded the Silent Circle secure communications company.

To legally circumvent the U.S. export restrictions on cryptographic software, Zimmermann published the complete PGP source code as a hardcover book via MIT Press in 1995. Because books are constitutionally protected under the First Amendment, the source code could be legally exported and scanned back into a computer. This clever legal maneuver effectively defeated the government's arms trafficking regulations.

Beyond email encryption, Zimmermann is the creator of the ZRTP protocol, which provides secure voice communication over the internet. This technology is the backbone of secure, end-to-end encrypted calling applications. He developed this to bring the same level of privacy offered by PGP to real-time voice and video calls.