BoxCryptor - Boxcryptor encrypts your sensitive files before uploading them to cloud storage services like Dropbox, Google Drive, Microsoft OneDrive, Box, and many others.
GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
EDS (Encrypted Data Store) - EDS (Encrypted Data Store) allows you to hide and protect your files inside an encrypted container. VeraCrypt(R), TrueCrypt(R), LUKS, EncFs, CyberSafe(R) container formats are supported.
GPG Suite - Use GPG Suite to encrypt, decrypt, sign and verify files or messages.
BoxWrap - Encrypts and protects your files on your machine, before they hit your disk and the cloud:...
Autocrypt - Convenient End-to-End Encryption for E-Mail