CrococryptFile - Strong file encryption tool
GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
File Encryption XP - A program designed for protecting confidential information stored on your computer.
GPG Suite - Use GPG Suite to encrypt, decrypt, sign and verify files or messages.
Autocrypt - Convenient End-to-End Encryption for E-Mail
VSEncryptor - VSEncryptor is an easy to use file and text encryption program.