From Libertarian Wiki

The use of electronic communications has severely decreased privacy for many Americans. Email is inherently unsecure, so various organizations have developed encryption systems so that we can expect the same type of privacy with email that we expect with traditional mail.

Encryption algorithems:

  • Gnu Privacy Guard
  • Pretty Good Privacy (widespread, but no longer maintained)

Front ends (user interfaces):

  • Windows Privacy Tray
  • Enigma (for Thunderbird email client)