Koch lives in Erkrath, near Düsseldorf, Germany. He began writing GNU Privacy Guard in 1997, inspired by attending a talk by Richard Stallman who made a call for someone to write a replacement for Phil Zimmermann's Pretty Good Privacy (PGP) which was subject to U.S. export restrictions.[2] The first release of GNU Privacy Guard was in 1999 and it went on to become the basis for most of the popular email encryption programs: GPGTools, Enigmail, and Koch's own Gpg4win, the primary free encryption program for Microsoft Windows.[2]
In 1999 Koch, via the German Unix User Group which he served on the board of,[2] received a grant of 318,000 Deutsche Mark (about US$170,000) from the German Federal Ministry of Economics and Technology to make GPG compatible with Microsoft Windows.[1] In 2005 he received a contract from the German government to support the development of S/MIME.
Journalists and security professionals rely on GnuPG, and Edward Snowden used it to evade monitoring whilst he leaked classified information from the U.S. National Security Agency.[4] Despite GnuPG's popularity, Koch has struggled to survive financially, earning about $25,000 per year since 2001[2] and thus considered abandoning the project and taking a better paying programming job.[4] However, given Snowden's leaked documents showed the extent of NSA surveillance, Koch continued.[4] In 2014 he held a funding drive and in response received $137,000 in donations from the public,[2] and Facebook and Stripe each pledged to annually donate $50,000 to GPG development.[2][5] Unrelated, in 2015 Koch was also awarded a one-time grant of $60,000 from the Linux Foundation's Core Infrastructure Initiative.[5][6]
