TextSecure is a free Android-based messaging app, completly open-source, easy to use and designed with privacy in mind. Latest release now offers encrypted group chat, media attachments and push messaging capabilities. In coming months TextSecure will be going fully cross-platform and will release an iOS app and a Web browser add-on. TextSecure provides frictionless end-to-end i.e. local encryption to solve the privacy and security issues. Messages that are sent or received with TextSecure are stored in an encrypted database.
Source: https://thehackernews.com/2014/03/textsecure-end-to-end-encrypted-and.html