Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
Knox - Knox offers easy disk image encryption and comes with a built-in backup service.
OpenKeychain - OpenKeychain helps you communicate more privately and securely.
Exocet - Exocet creates a Folder on your System.
Enigmail - Security extension to Mozilla Thunderbird and SeaMonkey
R-Crypto - R-Crypto is smart data security and disk encryption software that allows you to secure your sensitive information via strong encryption.