23 years ago, the first public version of PGP (Pretty Good Privacy) was released by Phil Zimmermann.
PGP made it possible for anybody to keep confidential data encrypted. PGP also made it possible for anybody to digitally sign files and emails before sharing them, so that the recipients can verify their authenticity.
Following the specification, the alternative implementation GnuPG was written, and support for PGP was made available for many email clients.
PGP implementations are still actively maintained, and there are no known ...