NetPGP is a standards-compliant library and suite of utilities providing digital signature and verification functionality, as well as data encryption and decryption, using RSA and DSA/Elgamal keys.
NetPGP was added to the NetBSD project in early 2009, and was presented at EuroBSDcon 2009, and its ability to interoperate with SSH keys at EuroBSDcon 2010.
The latest versions of the source code for netpgp and netpgpverify are licensed under a two-clause BSD license.
The frequently asked questions explains much, much more about NetPGP, its features, and what is coming in the roadmap.