TextSecure was an encrypted messaging application for
Android that was developed from 2010 to 2015. It was a predecessor to
Signal
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...
and the first application to use the
Signal Protocol
The Signal Protocol (formerly known as the TextSecure Protocol) is a non- federated cryptographic protocol that can be used to provide end-to-end encryption for voice calls and instant messaging conversations. The protocol was developed by Open ...
, which has since been implemented into
WhatsApp
WhatsApp (also called WhatsApp Messenger) is an internationally available freeware, cross-platform, centralized instant messaging (IM) and voice-over-IP (VoIP) service owned by American company Meta Platforms (formerly Facebook). It allows use ...
and other applications. TextSecure used
end-to-end encryption
End-to-end encryption (E2EE) is a system of communication where only the communicating users can read the messages. In principle, it prevents potential eavesdroppers – including telecommunications service providers, telecom providers, Internet ...
to secure the transmission of text messages, group messages, attachments and media messages to other TextSecure users.
TextSecure was first developed by
Whisper Systems, who were later
acqui-hired by
Twitter
Twitter is an online social media and social networking service owned and operated by American company Twitter, Inc., on which users post and interact with 280-character-long messages known as "tweets". Registered users can post, like, and ...
. The application's
source code
In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the w ...
was then released under a
free and open-source software license. In 2013, TextSecure's development was picked up by an independent group called
Open Whisper Systems, who merged it with an encrypted voice calling application called RedPhone and renamed the product as Signal.
History
Whisper Systems and Twitter (2010–2011)
TextSecure started as an application for sending and receiving encrypted SMS messages.
Its
beta version
A software release life cycle is the sum of the stages of development and maturity for a piece of computer software ranging from its initial development to its eventual release, and including updated versions of the released version to help impro ...
was first launched on May 25, 2010, by
Whisper Systems,
a startup company co-founded by security researcher
Moxie Marlinspike
Moxie Marlinspike is an American entrepreneur, cryptographer, and computer security researcher. Marlinspike is the creator of Signal, co-founder of the Signal Technology Foundation, and served as the first CEO of Signal Messenger LLC. He is als ...
and roboticist Stuart Anderson.
In addition to launching TextSecure, Whisper Systems produced a firewall, tools for encrypting other forms of data, and
RedPhone, an application that provided encrypted voice calls.
All of these were