PGP and GPG

• Both freely available implementations of PKI
• PGP - http://www.pgpi.org
  • Free for non-commercial use
  • Uses RSA and IDEA (still patented)
• GPG (GnuPG) - http://www.gnupg.org
  • GPLed
  • Uses DSA and ElGamel (no patent issues)
  • Recommended
• Modern versions can be interoperable
  • PGP users should encrypt with cast5 rather than IDEA
  • Possibly patent-infringing IDEA extension for GPG available as a module
• Both available for many platforms