Philip Zimmermann

Illustration by Anthony Russo, used with permission

Essays on PGP

Here are links to some stuff I've written on PGP:

Author's preface to the book: "PGP Source Code and Internals"
Published by The MIT Press, 1995. ISBN 0-262-24039-4.
(no longer in print)

Beware of Snake Oil
Part of the old original PGP User's Guide (updated in 1997)

Why I Wrote PGP
Part of the old original PGP User's Guide (updated in 1999)

Senate Testimony
Testimony to a US Senate subcommittee in June 1997

No Regrets About Developing PGP
Response to a post-9/11 Washington Post article about me

5 June 2001 PGP Marks 10th Anniversary

6 June 2021 PGP Marks 30th Anniversary


The Evolution of PGP's Web of Trust
Excerpt from the book "Beautiful Security", published by O'Reilly Media in 2009, ISBN 978-0-596-52748-8, The authors have made this essay available under a "CC BY" Creative Commons license.


John Perry Barlow's Foreword to the book: "The Official PGP User's Guide"
Published by The MIT Press, 1995. ISBN 0-262-74017-6.
(no longer in print)