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!
YAATA - YAATA app offers features that let you send multimedia files such as images, videos, audio, and GIFs, etc.
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
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.