GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
Knox - Knox offers easy disk image encryption and comes with a built-in backup service.
GPG Suite - Use GPG Suite to encrypt, decrypt, sign and verify files or messages.
R-Crypto - R-Crypto is smart data security and disk encryption software that allows you to secure your sensitive information via strong encryption.
Autocrypt - Convenient End-to-End Encryption for E-Mail
Exocet - Exocet creates a Folder on your System.