TextSecure was an encrypted messaging application for
Android that was developed from 2010 to 2015. It was a predecessor to
Signal
A signal is both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology.
In ...
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 provides end-to-end encryption for voice and instant messaging conversations. The protocol was developed by Open Whisper Systems in ...
, which has since been implemented into
WhatsApp
WhatsApp (officially WhatsApp Messenger) is an American social media, instant messaging (IM), and voice-over-IP (VoIP) service owned by technology conglomerate Meta. It allows users to send text, voice messages and video messages, make vo ...
and other applications. TextSecure used
end-to-end encryption
End-to-end encryption (E2EE) is a method of implementing a secure communication system where only communicating users can participate. No one else, including the system provider, telecom providers, Internet providers or malicious actors, can ...
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, officially known as X since 2023, is an American microblogging and social networking service. It is one of the world's largest social media platforms and one of the most-visited websites. Users can share short text messages, image ...
. The application's
source code
In computing, source code, or simply code or source, is a plain text computer program written in a programming language. A programmer writes the human readable source code to control the behavior of a computer.
Since a computer, at base, only ...
was then released under a
free and open-source software
Free and open-source software (FOSS) is software available under a license that grants users the right to use, modify, and distribute the software modified or not to everyone free of charge. FOSS is an inclusive umbrella term encompassing free ...
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
The software release life cycle is the process of developing, testing, and distributing a software product (e.g., an operating system). It typically consists of several stages, such as pre-alpha, alpha, beta, and release candidate, before the fi ...
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 (messaging app), Signal, co-founder of the Signal Technology Foundation, and served as the first CEO of Signal M ...
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