VeraCrypt - VeraCrypt is a free open source disk encryption software for Windows, Mac OSX and Linux.
Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
Knox - Knox offers easy disk image encryption and comes with a built-in backup service.
GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
Cryptomator - When it comes to saving your files on a cloud server, it is important to ensure the security of those files. Keeping your delicate files out of the wrong hands can save you a lot of time and hassle. Read more about Cryptomator.
GPG Suite - Use GPG Suite to encrypt, decrypt, sign and verify files or messages.