VeraCrypt - VeraCrypt is a free open source disk encryption software for Windows, Mac OSX and Linux.
GPG Suite - Use GPG Suite to encrypt, decrypt, sign and verify files or messages.
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).
Advanced File Security Basic - Download Advanced File Security Basic. Protect files by encrypting them with a strong password, a series of questions, or even an USB key you can carry around with this powerful security solution
File Encryption XP - A program designed for protecting confidential information stored on your computer.