Open Whisper Systems (abbreviated OWS[7]) was a software development group[8] that was founded by Moxie Marlinspike in 2013.

[5][10] Security researcher Moxie Marlinspike and roboticist Stuart Anderson co-founded a startup company called Whisper Systems in 2010.

[23] Toward the end of July 2014, Open Whisper Systems announced plans to unify its RedPhone and TextSecure applications as Signal.

[30] WhatsApp confirmed the partnership to reporters, but there was no announcement or documentation about the encryption feature on the official website, and further requests for comment were declined.

[32][33] In September 2016, Google launched a new messaging app called Allo, which features an optional "incognito mode" that uses the Signal Protocol for end-to-end encryption.

[42] At the same time, they announced the release of a standalone desktop client for certain Windows, MacOS and Linux distributions.

[42][43] On 4 October 2016, the American Civil Liberties Union (ACLU) and Open Whisper Systems published a series of documents revealing that OWS had received a subpoena requiring them to provide information associated with two phone numbers for a federal grand jury investigation in the first half of 2016.

"[5][47] The foundation was started with an initial $50 million in funding from Acton, who had left WhatsApp's parent company Facebook in September 2017.

Former NSA contractor Edward Snowden endorsed Open Whisper Systems applications,[56] including during an interview with The New Yorker in October 2014,[57] and during a remote appearance at an event hosted by Ryerson University and Canadian Journalists for Free Expression, in March 2015.

[61] In October 2014, the Electronic Frontier Foundation (EFF) included TextSecure, RedPhone, and Signal in their updated Surveillance Self-Defense (SSD) guide.

[63] They received points for having communications encrypted in transit, having communications encrypted with keys the providers don't have access to (end-to-end encryption), making it possible for users to independently verify their correspondent's identities, having past communications secure if the keys are stolen (forward secrecy), having their code open to independent review (open source), having their security designs well-documented, and having recent independent security audits.

[63] On 28 December 2014, Der Spiegel published slides from an internal NSA presentation dating to June 2012 in which the NSA deemed RedPhone on its own as a "major threat" to its mission, and when used in conjunction with other privacy tools such as Cspace, Tor, Tails, and TrueCrypt was ranked as "catastrophic," leading to a "near-total loss/lack of insight to target communications, presence..."[64][65] Over its five-year existence from 2013 to 2018, the Open Whisper Systems group managed multiple projects, which included:[66] Some of these projects were discontinued or merged into other projects: