Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
SMS Plus - SMS Plus app offers features that let you forward text messages through internet connection as well as through other social media platforms.
CrococryptFile - Strong file encryption tool
NetSfere Secure Messaging - NetSfere Secure Messaging is a secure messaging app that enables you to send messages by using 256-bit device-to-device encryption features.
VSEncryptor - VSEncryptor is an easy to use file and text encryption program.