PGP key:
Key-ID: 0xA2193FD7
Fingerprint: 9B77 7579 8F88 AD5F 1897 6E9E E5ED 103A A219 3FD7
Public PGP keys are available, e.g., at http://pgp.mit.edu/ and http://www.heise.de/security/dienste/Keyserver-474468.html
PGP open source software is available, e.g., at https://www.gnupg.org/