Phil Zimmermann

Phil Zimmermann phil blackphone foto

Philip R. “Phil” Zimmermann, Jr. (born February 12, 1954) is the creator of Pretty Good Privacy (PGP), the most widely used email encryption software in the world.



In 1991, he wrote the popular Pretty Good Privacy (PGP) program, and made it available (together with its source code) through public FTP for download, the first widely available program implementing public-key cryptography. Shortly thereafter, it became available overseas via the Internet, though Zimmermann has said he had no part in its distribution outside the United States.

The very first version of PGP included an encryption algorithm, BassOmatic, developed by Zimmermann.

Phil Zimmermann is the creator of Pretty Good Privacy (PGP), the most widely used email encryption software in the world. Phil is also a Co-Founder of Silent Circle, a provider of secure communications services. Before founding PGP Inc, Phil was a software engineer with more than 20 years of experience, specializing in cryptography and data security, data communications, and real-time embedded systems.

Arms Export Control Act investigation

After a report from RSA Security, who were in a licensing dispute with regard to the use of the RSA algorithm in PGP, the United States Customs Service started a criminal investigation of Zimmermann, for allegedly violating the Arms Export Control Act. The United States Government had long regarded cryptographic software as a munition, and thus subject to [[export of cryptography|arms trafficking export controls. At that time, the boundary between what cryptography was permitted (“low-strength”) and impermissible (“high-strength”) for export from the United States was placed such that PGP fell on the too-strong-to-export side of the boundary. The boundary for legal export has since been raised and now allows PGP to be exported. The investigation lasted three years, but was finally dropped without filing charges.

After the government dropped its case without indictment in early 1996, Zimmermann founded PGP Inc. and released an updated version of PGP and some additional related products. That company was acquired by Network Associates (NAI) in December 1997, and Zimmermann stayed on for three years as a Senior Fellow. NAI decided to drop the product line and in 2002, PGP was acquired from NAI by a new company called PGP Corporation. Zimmermann served as a special advisor and consultant to that firm until Symantec acquired PGP Corporation in 2010. Zimmermann is also a fellow at the Stanford Law School’s Center for Internet and Society. He was a principal designer of the cryptographic key agreement protocol (the “association model”) for the Wireless USB standard.

Silent Circle

Along with Mike Janke, in 2012 he created Silent Circle, a secure hardware and subscription based software security company.

Dark Mail Alliance

In October 2013, Zimmermann, along with other key employees from Silent Circle, teamed up with Lavabit founder Ladar Levison to create the Dark Mail Alliance. The goal of the organization is to work on a new protocol to replace PGP that will encrypt metadata, among other things that PGP is not capable of.

Zimmermann’s Law

In 2013, an article on Zimmermann’s Law quoted Phil Zimmermann as saying The natural flow of technology tends to move in the direction of making surveillance easier, and the ability of computers to track us doubles every eighteen months, in reference to Moore’s Law.

Awards and other recognition

Zimmermann has received numerous technical and humanitarian awards for his pioneering work in cryptography:

  • In 2012, Zimmermann was inducted into the Internet Hall of Fame by the Internet Society.
  • In 2008, PC World named Zimmermann one of the “Top 50 Tech Visionaries” of the last 50 years.
  • In 2006, eWeek ranked PGP 9th in the 25 Most Influential and Innovative Products introduced since the invention of the PC in 1981.
  • In 2003, Reason named him a “Hero of Freedom”
  • In 2001, Zimmermann was inducted into the CRN Industry Hall of Fame.
  • In 2000, InfoWorld named him one of the “Top 10 Innovators in E-business”.
  • In 1999, he received the Louis Brandeis Award from Privacy International.
  • In 1998, he received a Lifetime Achievement Award from Secure Computing Magazine.
  • In 1996, he received the Norbert Wiener Award for Social and Professional Responsibility for promoting the responsible use of technology.
  • In 1995, he received the Chrysler Design Award for Innovation, and the Pioneer Award from the Electronic Frontier Foundation.
  • In 1995, Newsweek also named Zimmermann one of the “Net 50”, the 50 most influential people on the Internet.

Simon Singh’s The Code Book devotes an entire chapter to Zimmermann and PGP.


  • The Official PGP User’s Guide, MIT Press, 1995
  • PGP Source Code and Internals, MIT Press, 1995

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