Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
Folder Lock - Folder Lock is a security software that helps you to password protect files, shred files, clean history, encrypt the personal documents and much more.
GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
Windows BitLocker - This topic provides a high-level overview of BitLocker, including a list of system requirements, practical applications, and deprecated features.
GPG Suite - Use GPG Suite to encrypt, decrypt, sign and verify files or messages.
My Lockbox - My Lockbox is a security software enabling you to password protect any folder on your computer.