Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
Homomorphic encryption - Homomorphic encryption by IBM allows you to perform computations on its encrypted data without first decrypting it.
Enigmail - Security extension to Mozilla Thunderbird and SeaMonkey
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.
OpenKeychain - OpenKeychain helps you communicate more privately and securely.
KETS Quantum Key Distribution - KETS Quantum Key Distribution service is a utility that allows future-proof, quantum-safe communications at ultra-low power in a low-cost Quantum Key Distribution chip.