GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
Autocrypt - Convenient End-to-End Encryption for E-Mail
GPG4Win - GPG4Win is an encryption program for files and emails. The program encrypts emails and files so that they can only be read by those intended to receive them.
Chatlink.com - Anonymous communication platform
VeraCrypt - VeraCrypt is a free open source disk encryption software for Windows, Mac OSX and Linux.