GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
PhoneLeash: SMS/MMS forwarding - PhoneLeash: SMS/MMS forwarding app offers features that let you forward your desired text messages and multimedia messages to your email or your other mobile phone so that you can access them later.
CrococryptFile - Strong file encryption tool
Cellcrypt - Cellcrypt app provides features so you can enjoy secure conference calling, messaging, and sharing of documents.
VSEncryptor - VSEncryptor is an easy to use file and text encryption program.
YAATA - YAATA app offers features that let you send multimedia files such as images, videos, audio, and GIFs, etc.