Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
PGP Everywhere - PGP Everywhere is an iPhone / iPad app that allows you to utilize the security of PGP encryption anywhere you type, in almost any app!
Enigmail - Security extension to Mozilla Thunderbird and SeaMonkey
Homomorphic encryption - Homomorphic encryption by IBM allows you to perform computations on its encrypted data without first decrypting it.
OpenKeychain - OpenKeychain helps you communicate more privately and securely.
DESlock+ - DESlock+ is a suite of encryption instruments designed to shield in opposition to unintended storage platforms like the loss of a USB stick or computer and to allow relaxed collaboration and information sharing within the boundaries.