Encrypto - Encrypto lets you encrypt files before sending them to friends or coworkers.
GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
EncFSMP - EncFSMP, a program to mount EncFS folders on Windows and OS X.
Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
File Lock PEA - Password-encryption of files and directories. File PEA encrypts files and folders with authenticated encryption to protect confidentiality and integrity. The program uses memory-hard key derivation functions to prevent custom hardware attacks.
PGP Tool - PGPTool allows you to encrypt and decrypt files. It's free and easy to use.