4 Send notification mails to user encrypted with GPG.
5 Each user can enable it and submit his public key under Settings-> Addon
6 -> "Secure Mail" Settings.
8 Use 'openpgp-php' library, a pure PHP implementation of GPG/PGP.
9 See [project repo](https://github.com/singpolyma/openpgp-php).
11 Need Friendica version > 3.3.2 to work.