PGP (Pretty Good Privacy)。

RFC 1991 曰く:

> PGP (Pretty Good Privacy) uses a combination of public-key and
> conventional encryption to provide security services for electronic
> mail messages and data files.  These services include confidentiality
> and digital signature.  PGP is widely used throughout the global
> computer community.  This document describes the format of "PGP
> files", i.e., messages that have been encrypted and/or signed with PGP.

> PGP was created by Philip Zimmermann and first released, in Version
> 1.0, in 1991. Subsequent versions have been designed and implemented
> by an all-volunteer collaborative effort under the design guidance of
> Philip Zimmermann.  PGP and Pretty Good Privacy are trademarks of
> Philip Zimmermann.


* 実装

- (本家) PGP <http://www.pgpi.com/>
-- PGP 2.x
-- PGP 5.x,6.x (OpenPGP)
- GnuPG <http://www.gnupg.org/>


* 参考

- <http://pgp.iijlab.net/>
- <http://www.openpksd.org/doclist.html>


[1] [CITE@ja[Facebook、ユーザー宛メールのPGP暗号化をサポート | TechCrunch Japan]]
([TIME[2015-06-02 11:55:02 +09:00]] 版)
<http://jp.techcrunch.com/2015/06/02/20150601facebook-now-supports-pgp-to-send-you-encrypted-emails/>