TextSecure is an Android free messaging app by Open Whisper Systems. As the name suggests, this app is source secure. This app provide users with secure end-to-end instant messaging that is encrypted and easy to use messaging service that are also fast. With it, you can send photos, group messages, instant messages, and other attachments. In November 2015, TextSecure was merged with an encrypted voice calling application called RedPhone and was renamed as Signal.