Open Whisper Systems

{{Short description|Open source software organization}} {{distinguish|text=Whisper Systems, a company that was acquired by Twitter, or Whisper, a product of WhisperText LLC}} {{Use dmy dates|date=February 2020}} {{Infobox organization | name = Open Whisper Systems | native_name = | native_name_lang = | named_after = | image = | image_size = | image_alt = | caption = | logo = Open WhisperSystems logo.png | logo_size = | logo_alt = | logo_caption = | map = | map_size = | map_alt = | map_caption = | map2 = | map2_size = | map2_alt = | map2_caption = | abbreviation = OWS | predecessor = | merged_into = | successor = Signal Technology Foundation | formation = {{start date and age|2013|01|21}}<ref name="welcome" /> | founder = Moxie Marlinspike<ref name="mashable1" /> | founding_location = | dissolved = {{end date and age|2018|1|10}}<ref name="de">{{cite web |title=Signal Technology Foundation |url=https://opencorporates.com/companies/us_de/6703098 |website=OpenCorporates |publisher=Delaware Department of State: Division of Corporations |access-date=13 February 2019 |date=15 July 2018}}</ref> | merger = | type = | tax_id =  | registration_id =  | status = | purpose = Software development<ref name="mashable1" /> | headquarters = | location = San Francisco, CA<ref name="Lee-2016-06-22">{{cite web|last1=Lee|first1=Micah|title=Battle of the Secure Messaging Apps: How Signal Beats WhatsApp|url=https://theintercept.com/2016/06/22/battle-of-the-secure-messaging-apps-how-signal-beats-whatsapp/|website=The Intercept|publisher=First Look Media|access-date=17 July 2016|date=22 June 2016}}</ref> | coordinates =  | region_served = | services = | products = Signal, Signal Protocol | methods = | fields = Free and open-source software, Cryptography, Mobile software | num_members = | num_members_year = | language = | owner =  | secretary_general = | leader_title = | leader_name = | leader_title2 = | leader_name2 = | leader_title3 = | leader_name3 = | leader_title4 = | leader_name4 = | board_of_directors = | key_people = | main_organ = | parent_organization = | subsidiaries = | secessions = | affiliations = | budget = | budget_year = | revenue = | revenue_year = | disbursements = | expenses = | expenses_year = | endowment = | num_staff = 2–6<ref name="signal-foundation" /><ref name="Disrupt-2017-09-18">{{cite interview |last=Marlinspike |first=Moxie |interviewer=Devin Coldewey |title=Moxie Marlinspike: Trust No One |url=https://techcrunch.com/video/moxie-marlinspike-trust-no-one/59c00fe185eb426ac28d4eb4/ |at=3:50 |publisher=Oath Inc. |location=San Francisco, CA |date=18 September 2017 |work=TechCrunch Disrupt SF 2017 |access-date=19 September 2017 |archive-date=23 February 2018 |archive-url=https://web.archive.org/web/20180223174444/https://techcrunch.com/video/moxie-marlinspike-trust-no-one/59c00fe185eb426ac28d4eb4/ |url-status=dead }}</ref> | num_staff_year = | num_volunteers = | num_volunteers_year = | slogan = | mission = | website = {{URL|https://whispersystems.org/}} | remarks = | former_name = | footnotes = }} '''Open Whisper Systems''' ('''OWS''')<ref>{{cite web|title=Signal Privacy Policy|url=https://signal.org/signal/privacy/|publisher=Open Whisper Systems|access-date=31 January 2018|archive-date=31 January 2018|archive-url=https://web.archive.org/web/20180131182045/https://signal.org/signal/privacy/|url-status=dead}}</ref> was a software development group<ref name="ONeill-2017-01-03"/> that was founded by Moxie Marlinspike in 2013. The group picked up the open source development of TextSecure and RedPhone, and was later responsible for starting the development of the Signal Protocol<ref>{{cite AV media|url=https://www.youtube.com/watch?v=7WnwSovjYMs|title=TextSecure Protocol: Present and Future|date=9 June 2015|people=Perrin, Trevor|publisher=NorthSec|time=0:21|access-date=24 September 2016|medium=Video}}</ref> and the Signal messaging app. In 2018, Signal Messenger was incorporated as an LLC by Moxie Marlinspike and Brian Acton and then rolled under the independent 501(c)(3) non-profit Signal Technology Foundation. Today, the Signal app is developed by Signal Messenger LLC, which is funded by the Signal Technology Foundation.<ref name="signal-foundation" /><ref name="propublica" />

==History==

===2010–2013: Background=== Security researcher Moxie Marlinspike and roboticist Stuart Anderson co-founded a startup company called Whisper Systems in 2010.<ref name="wired1" /><ref name="businessweek1" /> The company produced proprietary enterprise mobile security software. Among these were an encrypted texting program called TextSecure and an encrypted voice calling app called RedPhone.<ref name="forbes1" /> They also developed a firewall and tools for encrypting other forms of data.<ref name="wired1" />

In November 2011, Whisper Systems announced that it had been acquired by Twitter. The financial terms of the deal were not disclosed by either company.<ref name="venturebeat1" /> The acquisition was done "primarily so that Mr. Marlinspike could help the then-startup improve its security".<ref name="Yadron-2015">{{cite news|last1=Yadron|first1=Danny|title=Moxie Marlinspike: The Coder Who Encrypted Your Texts|url=https://www.wsj.com/articles/moxie-marlinspike-the-coder-who-encrypted-your-texts-1436486274|access-date=10 July 2015|work=The Wall Street Journal|date=9 July 2015|archive-date=12 July 2015|archive-url=https://web.archive.org/web/20150712035634/https://www.wsj.com/articles/moxie-marlinspike-the-coder-who-encrypted-your-texts-1436486274|url-status=live}}</ref> Shortly after the acquisition, Whisper Systems' RedPhone service was made unavailable.<ref name="forbes2" /> Some criticized the removal, arguing that the software was "specifically targeted [to help] people under repressive regimes" and that it left people like the Egyptians in "a dangerous position" during the events of the 2011 Egyptian revolution.<ref name="wired2" />

Twitter released TextSecure as free and open-source software under the GPLv3 license in December 2011.<ref name="wired1"/><ref name="twitter1" /><ref name="whispersys2" /><ref name="mashable2" /> RedPhone was also released under the same license in July 2012.<ref name="whispersys3" /> Marlinspike later left Twitter and founded Open Whisper Systems as a collaborative open source project for the continued development of TextSecure and RedPhone.<ref name="wired3" /><ref name="welcome" />

===2013–2018: Open Whisper Systems=== Marlinspike launched Open Whisper Systems' website in January 2013.<ref name="mashable1" /><ref name="welcome" />

In February 2014, Open Whisper Systems introduced the second version of their TextSecure Protocol (now Signal Protocol), which added end-to-end encrypted group chat and instant messaging capabilities to TextSecure.<ref>{{cite web |date=24 February 2014 |first=Brian |last=Donohue |url=https://threatpost.com/textsecure-sheds-sms-in-latest-version/104456 |title=TextSecure Sheds SMS in Latest Version |website=Threatpost |access-date=14 July 2016 |archive-date=15 February 2017 |archive-url=https://web.archive.org/web/20170215020451/https://threatpost.com/textsecure-sheds-sms-in-latest-version/104456/ |url-status=live }}</ref> Toward the end of July 2014, Open Whisper Systems announced plans to unify its RedPhone and TextSecure applications as Signal.<ref name="signal" /> These announcements coincided with the initial release of Signal as a RedPhone counterpart for iOS. The developers said that their next steps would be to provide TextSecure instant messaging capabilities for iOS, unify the RedPhone and TextSecure applications on Android, and launch a web client.<ref name="threatpost1" /> Signal was the first iOS app to enable easy, strongly encrypted voice calls for free.<ref name="wired3" /><ref name="techcrunch2" /> TextSecure compatibility was added to the iOS application in March 2015.<ref name="theintercept1" /><ref name="arstechnica1" />

On 18 November 2014, Open Whisper Systems announced a partnership with WhatsApp to provide end-to-end encryption by incorporating the Signal Protocol into each WhatsApp client platform.<ref name="techcrunch1" /> Open Whisper Systems said that they had already incorporated the protocol into the latest WhatsApp client for Android and that support for other clients, group/media messages, and key verification would be coming soon after.<ref name="whatsapp" /> 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.<ref name="fortune1" /> On 5 April 2016, WhatsApp and Open Whisper Systems announced that they had finished adding end-to-end encryption to "every form of communication" on WhatsApp, and that users could now verify each other's keys.<ref name="Metz-2016-04-05">{{cite magazine|last1=Metz|first1=Cade|title=Forget Apple vs. the FBI: WhatsApp Just Switched on Encryption for a Billion People|url=https://www.wired.com/2016/04/forget-apple-vs-fbi-whatsapp-just-switched-encryption-billion-people/|magazine=Wired|publisher=Condé Nast|access-date=5 April 2016|date=5 April 2016|archive-date=5 April 2016|archive-url=https://web.archive.org/web/20160405164942/http://www.wired.com/2016/04/forget-apple-vs-fbi-whatsapp-just-switched-encryption-billion-people/|url-status=live}}</ref><ref>{{cite web|last1=Lomas|first1=Natasha|title=WhatsApp completes end-to-end encryption rollout|url=https://techcrunch.com/2016/04/05/whatsapp-completes-end-to-end-encryption-rollout/|website=TechCrunch|publisher=AOL Inc.|access-date=5 April 2016|date=5 April 2016|archive-date=6 April 2016|archive-url=https://web.archive.org/web/20160406010346/http://techcrunch.com/2016/04/05/whatsapp-completes-end-to-end-encryption-rollout/|url-status=live}}</ref> 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.<ref name="Greenberg-2016-05-18">{{Cite magazine|last=Greenberg|first=Andy|url=https://www.wired.com/2016/05/allo-duo-google-finally-encrypts-conversations-end-end/|title=With Allo and Duo, Google Finally Encrypts Conversations End-to-End|magazine=Wired|publisher=Condé Nast|date=18 May 2016|access-date=14 July 2016|archive-date=2 February 2017|archive-url=https://web.archive.org/web/20170202161556/https://www.wired.com/2016/05/allo-duo-google-finally-encrypts-conversations-end-end/|url-status=live}}</ref><ref name="Gibbs-2016-9-21">{{cite web|last1=Gibbs|first1=Samuel|title=Google launches WhatsApp competitor Allo – with Google Assistant|url=https://www.theguardian.com/technology/2016/sep/21/google-whatsapp-allo-google-assistant|website=The Guardian|access-date=21 September 2016|date=21 September 2016|archive-date=7 January 2019|archive-url=https://web.archive.org/web/20190107054254/https://www.theguardian.com/technology/2016/sep/21/google-whatsapp-allo-google-assistant|url-status=live}}</ref> In October 2016, Facebook deployed an optional mode called "secret conversations" in Facebook Messenger mobile apps which provides end-to-end encryption using an implementation of the Signal Protocol.<ref>{{cite web|last1=Isaac|first1=Mike|title=Facebook to Add 'Secret Conversations' to Messenger App|url=https://www.nytimes.com/2016/07/09/technology/facebook-messenger-app-encryption.html|website=The New York Times|access-date=14 July 2016|date=8 July 2016|archive-date=12 July 2016|archive-url=https://web.archive.org/web/20160712043038/http://www.nytimes.com/2016/07/09/technology/facebook-messenger-app-encryption.html|url-status=live}}</ref><ref>{{cite magazine|last1=Greenberg|first1=Andy|title='Secret Conversations:' End-to-End Encryption Comes to Facebook Messenger|url=https://www.wired.com/2016/07/secret-conversations-end-end-encryption-facebook-messenger-arrived/|magazine=Wired|publisher=Condé Nast|access-date=14 July 2016|date=8 July 2016|archive-date=11 July 2016|archive-url=https://web.archive.org/web/20160711073318/https://www.wired.com/2016/07/secret-conversations-end-end-encryption-facebook-messenger-arrived/|url-status=live}}</ref><ref name="Greenberg-2016-10-05">{{cite magazine|last1=Greenberg|first1=Andy|url=https://www.wired.com/2016/10/facebook-completely-encrypted-messenger-update-now/|title=You Can All Finally Encrypt Facebook Messenger, So Do It|magazine=Wired|publisher=Condé Nast|access-date=5 October 2016|date=4 October 2016|archive-date=15 April 2017|archive-url=https://web.archive.org/web/20170415004558/https://www.wired.com/2016/10/facebook-completely-encrypted-messenger-update-now|url-status=live}}</ref>

In November 2015, the TextSecure and RedPhone applications on Android were merged to become Signal for Android.<ref name="Greenberg-2015-11-2">{{cite magazine|last1=Greenberg|first1=Andy|title=Signal, the Snowden-Approved Crypto App, Comes to Android|url=https://www.wired.com/2015/11/signals-snowden-approved-phone-crypto-app-comes-to-android/|magazine=Wired|publisher=Condé Nast|access-date=22 March 2016|date=2 November 2015|archive-date=26 January 2018|archive-url=https://web.archive.org/web/20180126050207/https://www.wired.com/2015/11/signals-snowden-approved-phone-crypto-app-comes-to-android/|url-status=live}}</ref> A month later, Open Whisper Systems announced Signal Desktop, a Chrome app that could link with a Signal client.<ref name="Motherboard-2015-12-02">{{cite web|last1=Franceschi-Bicchierai|first1=Lorenzo|title=Snowden's Favorite Chat App Is Coming to Your Computer|url=https://www.vice.com/en/article/signal-snowdens-favorite-chat-app-is-coming-to-your-computer/|website=Motherboard|publisher=Vice Media LLC|access-date=4 December 2015|date=2 December 2015|archive-date=5 December 2015|archive-url=https://web.archive.org/web/20151205073848/http://motherboard.vice.com/read/signal-snowdens-favorite-chat-app-is-coming-to-your-computer|url-status=live}}</ref> At launch, the app could only be linked with the Android version of Signal.<ref name="Motherboard-2015-12-02" /> On 26 September 2016, Open Whisper Systems announced that Signal Desktop could now be linked with the iOS version of Signal as well.<ref name="signal-desktop-ios">{{cite web|last1=Marlinspike|first1=Moxie|title=Desktop support comes to Signal for iPhone|url=https://whispersystems.org/blog/signal-desktop-ios/|publisher=Open Whisper Systems|access-date=26 September 2016|date=26 September 2016|archive-date=7 July 2017|archive-url=https://web.archive.org/web/20170707095128/https://whispersystems.org/blog/signal-desktop-ios/|url-status=live}}</ref> On 31 October 2017, Open Whisper Systems announced that the Chrome app was deprecated.<ref name="standalone-signal-desktop"/> At the same time, they announced the release of a standalone desktop client for certain Windows, MacOS and Linux distributions.<ref name="standalone-signal-desktop">{{cite web|last1=Nonnenberg|first1=Scott|title=Standalone Signal Desktop|url=https://signal.org/blog/standalone-signal-desktop/|publisher=Open Whisper Systems|access-date=31 October 2017|date=31 October 2017|archive-date=15 February 2020|archive-url=https://web.archive.org/web/20200215121725/https://signal.org/blog/standalone-signal-desktop/|url-status=live}}</ref><ref name="Coldewey-2017-10-31"/>

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.<ref name="Perlroth-2016-10-04">{{cite web|last1=Perlroth|first1=Nicole|last2=Benner|first2=Katie|title=Subpoenas and Gag Orders Show Government Overreach, Tech Companies Argue|url=https://www.nytimes.com/2016/10/05/technology/subpoenas-and-gag-orders-show-government-overreach-tech-companies-argue.html|website=The New York Times|access-date=4 October 2016|date=4 October 2016|archive-date=24 January 2020|archive-url=https://web.archive.org/web/20200124010809/https://www.nytimes.com/2016/10/05/technology/subpoenas-and-gag-orders-show-government-overreach-tech-companies-argue.html|url-status=live}}</ref><ref name="Kaufman-2016-10-04">{{cite web|last1=Kaufman|first1=Brett Max|title=New Documents Reveal Government Effort to Impose Secrecy on Encryption Company|url=https://www.aclu.org/blog/free-future/new-documents-reveal-government-effort-impose-secrecy-encryption-company|publisher=American Civil Liberties Union|type=Blog post|access-date=4 October 2016|date=4 October 2016|archive-date=25 July 2017|archive-url=https://web.archive.org/web/20170725085001/https://www.aclu.org/blog/free-future/new-documents-reveal-government-effort-impose-secrecy-encryption-company|url-status=live}}</ref><ref name="OWS-2016-10-04">{{cite web|title=Grand jury subpoena for Signal user data, Eastern District of Virginia|url=https://whispersystems.org/bigbrother/eastern-virginia-grand-jury/|publisher=Open Whisper Systems|access-date=4 October 2016|date=4 October 2016|archive-date=29 August 2017|archive-url=https://web.archive.org/web/20170829091039/https://whispersystems.org/bigbrother/eastern-virginia-grand-jury/|url-status=live}}</ref> Only one of the two phone numbers was registered on Signal, and because of how the service is designed, OWS was only able to provide "the time the user’s account had been created and the last time it had connected to the service".<ref name="Kaufman-2016-10-04"/><ref name="Perlroth-2016-10-04"/> Along with the subpoena, OWS received a gag order requiring OWS not to tell anyone about the subpoena for one year.<ref name="Perlroth-2016-10-04"/> OWS approached the ACLU, and they were able to lift part of the gag order after challenging it in court.<ref name="Perlroth-2016-10-04"/> OWS said it was the first time they had received a subpoena, and that they were committed to treat "any future requests the same way".<ref name="OWS-2016-10-04"/>

===2018–present: Signal Foundation=== {{Main|Signal Foundation|Signal Protocol|Signal (messaging app)}}

On February 21, 2018, Moxie Marlinspike and WhatsApp co-founder Brian Acton announced the formation of the Signal Foundation, a 501(c)(3) non-profit organization whose mission is "to support, accelerate, and broaden Signal’s mission of making private communication accessible and ubiquitous."<ref name="signal-foundation">{{cite web|last1=Marlinspike|first1=Moxie|last2=Acton|first2=Brian|title=Signal Foundation|url=https://signal.org/blog/signal-foundation/|website=Signal.org|access-date=21 February 2018|date=21 February 2018|archive-date=16 February 2020|archive-url=https://web.archive.org/web/20200216021349/https://signal.org/blog/signal-foundation/|url-status=live}}</ref><ref name="Greenberg-2018-02-21"/> The foundation was started with an initial $50 million in funding from Acton, who had left WhatsApp's parent company Facebook in September 2017.<ref name="Greenberg-2018-02-21">{{cite magazine|last1=Greenberg|first1=Andy|title=WhatsApp Co-Founder Puts $50M Into Signal To Supercharge Encrypted Messaging|url=https://www.wired.com/story/signal-foundation-whatsapp-brian-acton/|magazine=Wired|publisher=Condé Nast|access-date=21 February 2018|date=21 February 2018|archive-date=22 February 2018|archive-url=https://web.archive.org/web/20180222022309/https://www.wired.com/story/signal-foundation-whatsapp-brian-acton/|url-status=live}}</ref> According to the announcement, Acton is the foundation's executive chairman and Marlinspike continued as CEO of Signal Messenger.<ref name="signal-foundation"/> The Freedom of the Press Foundation agreed to continue accepting donations on behalf of Signal while the Signal Foundation's non-profit status was pending.<ref name="signal-foundation" /> The Signal Foundation became officially tax-exempt in February 2019.<ref name="propublica" />

==Funding== In May 2014, Moxie Marlinspike said that "Open Whisper Systems is a project rather than a company, and the project's objective is not financial profit."<ref>{{cite web|last1=Marlinspike|first1=Moxie|title=What is TextSecure's business model?|url=https://news.ycombinator.com/item?id=7701666|website=Hacker News|access-date=4 February 2017|date=6 May 2014|archive-date=5 February 2017|archive-url=https://web.archive.org/web/20170205095539/https://news.ycombinator.com/item?id=7701666|url-status=live}}</ref> News media outlets later described Open Whisper Systems as a "non-profit software group"<ref name="wired3" /><ref name="mashable1" /> while the project was not registered as a non-profit organization.<ref name="ONeill-2017-01-03">{{cite web|last1=O'Neill|first1=Patrick|title=How Tor and Signal can maintain the fight for freedom in Trump's America|url=https://www.cyberscoop.com/tor-signal-funding-donald-trump-steve-bannon-encryption/|website=CyberScoop|publisher=Scoop News Group|access-date=25 January 2017|date=3 January 2017|archive-date=17 September 2017|archive-url=https://web.archive.org/web/20170917033354/https://www.cyberscoop.com/tor-signal-funding-donald-trump-steve-bannon-encryption/|url-status=live}}</ref><ref name="signal-foundation"/> Between 2013 and 2016, Open Whisper Systems received grants from the Shuttleworth Foundation,<ref name="shuttleworthfoundation" /> the Knight Foundation,<ref name="knightfoundation" /> and the Open Technology Fund.<ref name="opentechfund" />

Signal Messenger was initially funded by donations through the Freedom of the Press Foundation,<ref name="ONeill-2017-01-03"/><ref>{{cite web|last1=Kolenkina|first1=Masha|title=How can I donate?|url=https://support.signal.org/hc/en-us/articles/212940158-How-can-I-donate-|website=Signal Support Center|publisher=Open Whisper Systems|access-date=31 January 2018|archive-date=30 January 2018|archive-url=https://web.archive.org/web/20180130032505/https://support.signal.org/hc/en-us/articles/212940158-How-can-I-donate-|url-status=dead}}</ref> which acted as Signal Messenger's fiscal sponsor while the Signal Foundation's non-profit status was pending.<ref name="signal-foundation" /><ref name="Timm-2017-01-25">{{cite web|last1=Timm|first1=Trevor|title=Freedom of the Press Foundation's new look, and our plans to protect press freedom for 2017|url=https://freedom.press/news/freedom-press-foundations-new-look-and-our-plans-protect-press-freedom-2017/|website=Freedom of the Press Foundation|access-date=25 January 2017|date=8 December 2016|archive-date=2 February 2017|archive-url=https://web.archive.org/web/20170202042832/https://freedom.press/news/freedom-press-foundations-new-look-and-our-plans-protect-press-freedom-2017/|url-status=live}}</ref><ref name="pressfreedomfoundation" /> The Signal Foundation is officially tax-exempt as of February 2019.<ref name="propublica">{{cite web |title=Signal Technology Foundation |url=https://projects.propublica.org/nonprofits/organizations/824506840 |website=Nonprofit Explorer |date=9 May 2013 |publisher=Pro Publica Inc. |access-date=7 June 2019 |archive-date=9 January 2021 |archive-url=https://web.archive.org/web/20210109161310/https://projects.propublica.org/nonprofits/organizations/824506840 |url-status=live }}</ref>

In January 2021, the tech billionaire Elon Musk [https://twitter.com/elonmusk/status/1347165127036977153?lang=en tweeted his support for the Signal app] with two words "Use Signal", showing his favor for the app as an alternative to WhatsApp. Musk doubled down stating he had financially supported Signal in the past and that he will continue to do so.<ref>{{Cite news|last=Robles|first=CJ|date=January 12, 2021|title=Elon Musk Promises to 'Donate More' Funds to Signal App After Last Week's Stocks Fiasco|work=Tech Times|url=https://www.techtimes.com/articles/255842/20210112/elon-musk-donate-more-funds-signal-app.htm|access-date=January 29, 2021}}</ref> In addition to other platform mass migrations, Signal saw a large influx of new users and user donations.

==Reception== Former NSA contractor Edward Snowden endorsed Open Whisper Systems applications,<ref name="pcmag-snowden" /> including during an interview with ''The New Yorker'' in October 2014,<ref name="thenewyorker-snowden" /> and during a remote appearance at an event hosted by Ryerson University and Canadian Journalists for Free Expression, in March 2015.<ref name="dailydot-snowden" /> Asked about encrypted messaging apps during a Reddit AMA in May 2015, he recommended "Signal for iOS, Redphone/TextSecure for Android".<ref name="theguardian-snowden" /><ref name="voxmedia-snowden" /> In November 2015, Snowden tweeted that he used Signal "every day".<ref name="Barrett-2016-02">{{cite magazine|last1=Barrett|first1=Brian|title=Apple Hires Lead Dev of Snowden's Favorite Messaging App|url=https://www.wired.com/2016/02/apple-hires-lead-dev-snowdens-favorite-messaging-app/|magazine=Wired|publisher=Condé Nast|access-date=2 March 2016|date=25 February 2016|archive-date=29 February 2016|archive-url=https://web.archive.org/web/20160229021922/http://www.wired.com/2016/02/apple-hires-lead-dev-snowdens-favorite-messaging-app/|url-status=live}}</ref>

In October 2014, the Electronic Frontier Foundation (EFF) included TextSecure, RedPhone, and Signal in their updated Surveillance Self-Defense (SSD) guide.<ref name="eff2" /> In November 2014, all three received top scores on the EFF's Secure Messaging Scorecard, along with Cryptocat, Silent Phone, and Silent Text.<ref name="eff1" /> 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.<ref name="eff1" />

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..."<ref name="spiegel1" /><ref name="spiegel2" />

==Projects== Over its five-year existence from 2013 to 2018, the Open Whisper Systems group managed multiple projects, which included:<ref name="gh-whispersystems">{{cite web |url=https://github.com/signalapp |title=Signal |website=GitHub |access-date=13 February 2019 |archive-date=2 February 2019 |archive-url=https://web.archive.org/web/20190202034433/https://github.com/signalapp |url-status=live }}</ref> thumb|right|100px|''Signal'' * '''Signal''': An instant messaging, voice calling and video calling<ref name="Mott-2017-03-14">{{cite web|last1=Mott|first1=Nathaniel|title=Signal's Encrypted Video Calling For iOS, Android Leaves Beta|url=http://www.tomshardware.com/news/signal-encrypted-video-calling-ios-android,33898.html|website=Tom's Hardware|publisher=Purch Group, Inc.|date=14 March 2017|access-date=14 March 2017}}</ref> application for Android, iOS and desktop.<ref name="Coldewey-2017-10-31">{{cite web|last1=Coldewey|first1=Devin|title=Signal escapes the confines of the browser with a standalone desktop app|url=https://techcrunch.com/2017/10/31/signal-escapes-the-confines-of-the-browser-with-a-standalone-desktop-app/|website=TechCrunch|publisher=Oath Tech Network|access-date=31 October 2017|date=31 October 2017|archive-date=14 May 2019|archive-url=https://web.archive.org/web/20190514155929/https://techcrunch.com/2017/10/31/signal-escapes-the-confines-of-the-browser-with-a-standalone-desktop-app/|url-status=live}}</ref> It uses end-to-end encryption protocols to secure all communications to other Signal users.<ref name="arstechnica1" /><ref name="eff1" /> Signal can be used to send end-to-end encrypted group messages, attachments and media messages to other Signal users. The app uses 4 encryption algorithms to encrypt all text and media sent to and from the app: XEdDSA and VXEdDSA, Double Ratchet, X3DH, and Sesame.{{cn|date=February 2021}} All calls are made over a Wi-Fi or data connection and are free of charge, including long distance and international.<ref name="techcrunch2" /> Signal has a built-in mechanism for verifying that no man-in-the-middle attack has occurred. Signal Messenger has set up dozens of servers to handle the encrypted calls in more than 10 countries around the world to minimize latency.<ref name="wired3" /> The clients are published under the GPLv3 license.<ref name="signal-ios-github" /><ref name="signal-android-github"/><ref name="signal-desktop-github"/> * '''Signal Protocol''': A non-federated cryptographic protocol that can be used to provide end-to-end encryption. It combines the Double Ratchet algorithm, prekeys, and a 3-DH handshake.<ref>{{harvnb|Unger|Dechand|Bonneau|Fahl|2015|p=241}}</ref> Signal Messenger maintains several open source Signal Protocol libraries on GitHub.<ref>{{cite web |url=https://github.com/signalapp/libsignal-protocol-c |title=libsignal-protocol-c |author=Signal Messenger LLC |website=GitHub |access-date=13 February 2019 |archive-date=12 November 2020 |archive-url=https://web.archive.org/web/20201112000826/https://github.com/signalapp/libsignal-protocol-c |url-status=live }}</ref><ref>{{cite web|title=libsignal-protocol-java|url=https://github.com/signalapp/libsignal-protocol-java|website=GitHub|author=Signal Messenger LLC|access-date=13 February 2019|archive-date=21 November 2020|archive-url=https://web.archive.org/web/20201121073134/https://github.com/signalapp/libsignal-protocol-java|url-status=live}}</ref><ref>{{cite web|title=libsignal-protocol-javascript|url=https://github.com/signalapp/libsignal-protocol-javascript|website=GitHub|author=Signal Messenger LLC|access-date=25 September 2016|archive-date=12 November 2020|archive-url=https://web.archive.org/web/20201112015236/https://github.com/signalapp/libsignal-protocol-javascript|url-status=live}}</ref><ref>{{cite web |title=libsignal-client |url=https://github.com/signalapp/libsignal-client |website=GitHub |author=Signal Messenger LLC |access-date=24 December 2020 |archive-date=8 January 2021 |archive-url=https://web.archive.org/web/20210108104702/https://github.com/signalapp/libsignal-client |url-status=live }}</ref> * {{Visible anchor|Signal Server|text='''Signal Server'''}}: The software is published under the AGPLv3 license.<ref name="Signal-Server" /> * {{Visible anchor|Contact Discovery Service|text='''Contact Discovery Service'''}}: A microservice that "allows clients to discover which of their contacts are registered users, but does not reveal their contacts to the service operator or any party that may have compromised the service."<ref name="ContactDiscoveryService"/> The software is published under the AGPLv3 license.<ref name="ContactDiscoveryService">{{cite web|title=Contact Discovery Service|url=https://github.com/signalapp/ContactDiscoveryService/|website=GitHub|publisher=Open Whisper Systems|access-date=28 September 2017|archive-date=26 June 2018|archive-url=https://web.archive.org/web/20180626223429/https://github.com/signalapp/ContactDiscoveryService|url-status=live}}</ref> {{As of|2017|09|26}}, the service is in beta.<ref name="private-contact-discovery">{{cite web|last1=Marlinspike|first1=Moxie|title=Technology preview: Private contact discovery for Signal|url=https://signal.org/blog/private-contact-discovery/|publisher=Open Whisper Systems|access-date=28 September 2017|date=26 September 2017|archive-date=28 September 2017|archive-url=https://web.archive.org/web/20170928043707/https://signal.org/blog/private-contact-discovery/|url-status=live}}</ref><ref>{{cite magazine|last1=Greenberg|first1=Andy|title=Signal Has a Fix for Apps' Contact-Leaking Problem|url=https://www.wired.com/story/signal-contact-lists-private-secure-enclave|magazine=Wired|publisher=Condé Nast|access-date=28 September 2017|date=26 September 2017|archive-date=27 September 2017|archive-url=https://web.archive.org/web/20170927143335/https://www.wired.com/story/signal-contact-lists-private-secure-enclave|url-status=live}}</ref>

Some of these projects were discontinued or merged into other projects: * {{Visible anchor|BitHub|text='''BitHub'''}}: A service that would automatically pay a percentage of Bitcoin funds for every submission to a GitHub repository.<ref name="bithub-gh" /><ref>{{cite magazine|last1=Finley|first1=Klint|title=Love Child of Bitcoin and GitHub Pays Cash for Code|url=https://www.wired.com/2013/12/bithub/|magazine=Wired|publisher=Condé Nast|access-date=22 September 2015|date=17 December 2013|archive-date=18 September 2015|archive-url=https://web.archive.org/web/20150918073105/http://www.wired.com/2013/12/bithub|url-status=live}}</ref><ref name="bithub-commit">{{cite web|last1=Marlinspike|first1=Moxie|last2=Rizzio|first2=Nicholas|title=Remove the last references to BitHub and Coinbase|url=https://github.com/signalapp/Signal-Android/commit/99ea6f98126ed502915ab377c13af422647915de|website=GitHub|access-date=31 January 2018|date=11 November 2017|archive-date=9 January 2021|archive-url=https://web.archive.org/web/20210109161433/https://github.com/signalapp/Signal-Android/commit/99ea6f98126ed502915ab377c13af422647915de|url-status=live}}</ref> * {{Visible anchor|Flock|text='''Flock'''}}: A service that synced calendar and contact information on Android devices. Users had the ability to host their own server. The developer cited technological choices that led to high server costs as a reason for discontinuing the service.<ref>{{cite web|url=https://gist.github.com/rhodey/873ae9d527d8d2a38213|title=RE: Flock shutting down|website=GitHub Gist|author=rhodey|date=16 July 2015|access-date=8 September 2015|archive-date=29 September 2015|archive-url=https://web.archive.org/web/20150929130810/https://gist.github.com/rhodey/873ae9d527d8d2a38213|url-status=live}}</ref> Flock was discontinued 1 October 2015, but its source code is still available on GitHub under the GPLv3 license.<ref name="Flock-GH" /> thumb|right|100px|''RedPhone'' * {{Visible anchor|RedPhone|text='''RedPhone'''}}: A stand-alone application for encrypted voice calling on Android. RedPhone integrated with the system dialler to make calls, but used ZRTP to set up an end-to-end encrypted VoIP channel for the actual call. RedPhone was designed specifically for mobile devices, using audio codecs and buffer algorithms tuned to the characteristics of mobile networks, and used push notifications to preserve the user's device's battery life while still remaining responsive.<ref name="RedPhone" /> RedPhone was merged into TextSecure on 2 November 2015.<ref name="Greenberg-2015-11-2"/> TextSecure was then renamed as Signal for Android.<ref name="Greenberg-2015-11-2"/> RedPhone's source code was available under the GPLv3 license.<ref name="RedPhone" /> thumb|right|100px|''TextSecure'' * '''TextSecure''': A stand-alone application for encrypted messaging on Android.<ref name="textsecure" /><ref name="nyt1" /> TextSecure could be used to send and receive SMS, MMS, and instant messages.<ref name="motherboard1" /> It used end-to-end encryption with forward secrecy and deniable authentication to secure all instant messages to other TextSecure users.<ref name="eff1" /><ref name="nyt1" /><ref name="the-new-textsecure" /><ref name="ghacks1" /> TextSecure was merged with RedPhone to become Signal for Android,<ref name="Greenberg-2015-11-2"/> but lost its ability to encrypt SMS. The source code is available under the GPLv3 license.<ref name="textsecure" />

==See also== {{Portal| Freedom of speech | Free and open-source software |Telecommunications}} * Comparison of instant messaging clients * Comparison of VoIP software * Internet privacy * List of free and open-source software organizations * Secure communication {{Clear}}

==References== {{Reflist|30em|refs=

<ref name="theintercept1">{{cite web |author=Micah Lee |url=https://firstlook.org/theintercept/2015/03/02/signal-iphones-encrypted-messaging-app-now-supports-text/ |title=You Should Really Consider Installing Signal, an Encrypted Messaging App for iPhone |website=The Intercept |date=2 March 2015 |access-date=3 March 2015 |archive-date=3 March 2015 |archive-url=https://web.archive.org/web/20150303052746/https://firstlook.org/theintercept/2015/03/02/signal-iphones-encrypted-messaging-app-now-supports-text/ |url-status=live }}</ref>

<ref name="arstechnica1">{{cite web |url=https://arstechnica.com/security/2015/03/now-you-can-easily-send-free-encrypted-messages-between-android-ios/ |title=Now you can easily send (free!) encrypted messages between Android, iOS |website=Ars Technica |author=Megan Geuss |date=3 March 2015 |access-date=4 March 2015 |archive-date=3 March 2015 |archive-url=https://web.archive.org/web/20150303214004/http://arstechnica.com/security/2015/03/now-you-can-easily-send-free-encrypted-messages-between-android-ios/ |url-status=live }}</ref>

<ref name="eff2">{{cite web | url = https://ssd.eff.org/en/module/communicating-others | publisher = Electronic Frontier Foundation | title = Surveillance Self-Defense. Communicating with Others | date = 23 October 2014 | access-date = 25 January 2015 | archive-date = 8 November 2014 | archive-url = https://web.archive.org/web/20141108170218/https://ssd.eff.org/en/module/communicating-others | url-status = live }}</ref>

<ref name="spiegel2">{{cite magazine|title=Presentation from the SIGDEV Conference 2012 explaining which encryption protocols and techniques can be attacked and which not|url=http://www.spiegel.de/media/media-35535.pdf|magazine=Der Spiegel|access-date=23 January 2015|date=28 December 2014|archive-date=8 October 2018|archive-url=https://web.archive.org/web/20181008114248/http://www.spiegel.de/media/media-35535.pdf|url-status=live}}</ref>

<ref name="spiegel1">{{cite news|author=SPIEGEL Staff|title=Prying Eyes: Inside the NSA's War on Internet Security|url=http://www.spiegel.de/international/germany/inside-the-nsa-s-war-on-internet-security-a-1010361.html|newspaper=Der Spiegel|access-date=23 January 2015|date=28 December 2014|archive-date=24 January 2015|archive-url=https://web.archive.org/web/20150124202809/http://www.spiegel.de/international/germany/inside-the-nsa-s-war-on-internet-security-a-1010361.html|url-status=live}}</ref>

<ref name="mashable1">{{cite web|last1=Franceschi-Bicchierai|first1=Lorenzo|title=WhatsApp messages now have Snowden-approved encryption on Android|url=http://mashable.com/2014/11/18/whatsapp-encryption-textsecure/|publisher=Mashable|access-date=23 January 2015|date=18 November 2014|archive-date=23 January 2015|archive-url=https://web.archive.org/web/20150123050951/http://mashable.com/2014/11/18/whatsapp-encryption-textsecure/|url-status=live}}</ref>

<ref name="twitter1">{{cite web |url=https://blog.twitter.com/2011/whispers-are-true |title= The Whispers Are True |archive-url= https://web.archive.org/web/20141024130437/https://blog.twitter.com/2011/whispers-are-true |archive-date= 24 October 2014 |date= 20 December 2011 |website=The Twitter Developer Blog |author=Chris Aniszczyk |publisher=Twitter |access-date=22 January 2015}}</ref>

<ref name="whispersys2">{{cite web |url=http://www.whispersys.com/updates.html |title= TextSecure is now Open Source! |archive-url= https://web.archive.org/web/20120106024504/http://www.whispersys.com/updates.html |archive-date= 6 January 2012 |date= 20 December 2011 |publisher=Whisper Systems |access-date=22 January 2015}}</ref>

<ref name="whispersys3">{{cite web |url=http://www.whispersys.com/updates.html |title= RedPhone is now Open Source! |archive-url= https://web.archive.org/web/20120731143138/http://www.whispersys.com/updates.html |archive-date= 31 July 2012 |date= 18 July 2012 |publisher=Whisper Systems |access-date=22 January 2015}}</ref>

<ref name="businessweek1">{{cite magazine|url=http://investing.businessweek.com/research/stocks/private/snapshot.asp?privcapId=141104009|archive-url=https://archive.today/20140304095526/http://investing.businessweek.com/research/stocks/private/snapshot.asp?privcapId=141104009|url-status=dead|archive-date=4 March 2014|title=Company Overview of Whisper Systems Inc. |magazine=Bloomberg Businessweek |access-date=4 March 2014}}</ref>

<ref name="forbes1">{{cite magazine |author=Andy Greenberg |url=https://www.forbes.com/sites/firewall/2010/05/25/android-app-aims-to-allow-wiretap-proof-cell-phone-calls/ |title=Android App Aims to Allow Wiretap-Proof Cell Phone Calls |magazine=Forbes |date=25 May 2010 |access-date=28 February 2014 |archive-date=21 January 2012 |archive-url=https://web.archive.org/web/20120121093240/http://www.forbes.com/sites/firewall/2010/05/25/android-app-aims-to-allow-wiretap-proof-cell-phone-calls |url-status=live }}</ref>

<ref name="forbes2">{{cite magazine |author=Andy Greenberg |url=https://www.forbes.com/sites/andygreenberg/2011/11/28/twitter-acquires-moxie-marlinspikes-encryption-startup-whisper-systems/ |title=Twitter Acquires Moxie Marlinspike's Encryption Startup Whisper Systems |magazine=Forbes |date=28 November 2011 |access-date=21 December 2011 |archive-date=14 December 2011 |archive-url=https://web.archive.org/web/20111214035729/http://www.forbes.com/sites/andygreenberg/2011/11/28/twitter-acquires-moxie-marlinspikes-encryption-startup-whisper-systems/ |url-status=live }}</ref>

<ref name="wired1">{{cite magazine |last=Garling |first=Caleb |url=https://www.wired.com/wiredenterprise/2011/12/twitter-open-sources-its-android-moxie/ |title=Twitter Open Sources Its Android Moxie | Wired Enterprise |magazine=Wired |date=20 December 2011 |access-date=21 December 2011 |archive-date=22 December 2011 |archive-url=https://web.archive.org/web/20111222010355/http://www.wired.com/wiredenterprise/2011/12/twitter-open-sources-its-android-moxie/ |url-status=live }}</ref>

<ref name="wired2">{{cite magazine |last=Garling |first=Caleb |url=https://www.wired.com/wiredenterprise/2011/11/twitter-buys-moxie/ |title=Twitter Buys Some Middle East Moxie | Wired Enterprise |magazine=Wired |date=28 November 2011 |access-date=21 December 2011 |archive-date=22 December 2011 |archive-url=https://web.archive.org/web/20111222020936/http://www.wired.com/wiredenterprise/2011/11/twitter-buys-moxie |url-status=live }}</ref>

<ref name="wired3">{{cite magazine |url= https://www.wired.com/2014/07/free-encrypted-calling-finally-comes-to-the-iphone/ |title= Your iPhone Can Finally Make Free, Encrypted Calls |magazine= Wired |author= Andy Greenberg |date= 29 July 2014 |access-date= 18 January 2015 |archive-date= 18 January 2015 |archive-url= https://web.archive.org/web/20150118152718/http://www.wired.com/2014/07/free-encrypted-calling-finally-comes-to-the-iphone/ |url-status= live }}</ref>

<ref name="venturebeat1">{{cite news |date=28 November 2011 |author=Tom Cheredar |url=https://venturebeat.com/2011/11/28/twitter-buys-whisper-systems/ |title=Twitter acquires Android security startup Whisper Systems |work=VentureBeat |access-date=21 December 2011 |archive-date=12 December 2011 |archive-url=https://web.archive.org/web/20111212035416/http://venturebeat.com/2011/11/28/twitter-buys-whisper-systems/ |url-status=live }}</ref>

<ref name="mashable2">{{cite news |url=http://mashable.com/2011/12/20/textsecure-open-source/ |author=Pete Pachal |title=Twitter Takes TextSecure, Texting App for Dissidents, Open Source |publisher=Mashable |date=20 December 2011 |access-date=1 March 2014 |archive-date=7 March 2014 |archive-url=https://web.archive.org/web/20140307173850/http://mashable.com/2011/12/20/textsecure-open-source/ |url-status=live }}</ref>

<ref name="pcmag-snowden">{{cite web |date=11 March 2014 |author=Max Eddy |url=http://securitywatch.pcmag.com/security/321511-snowden-to-sxsw-here-s-how-to-keep-the-nsa-out-of-your-stuff |title=Snowden to SXSW: Here's How To Keep The NSA Out Of Your Stuff |publisher=PC Magazine: SecurityWatch |access-date=16 March 2014 |archive-date=16 March 2014 |archive-url=https://web.archive.org/web/20140316122922/http://securitywatch.pcmag.com/security/321511-snowden-to-sxsw-here-s-how-to-keep-the-nsa-out-of-your-stuff |url-status=live }}</ref>

<ref name="thenewyorker-snowden">{{cite web |url=https://www.youtube.com/watch?v=fidq3jow8bc |title=The Virtual Interview: Edward Snowden - The New Yorker Festival |publisher=The New Yorker |website=YouTube |date=11 October 2014 |access-date=24 May 2015 |archive-date=9 January 2021 |archive-url=https://web.archive.org/web/20210109161401/https://www.youtube.com/watch?v=fidq3jow8bc |url-status=live }}</ref>

<ref name="dailydot-snowden">{{cite news |title= Edward Snowden tells you what encrypted messaging apps you should use |url= http://www.dailydot.com/politics/edward-snowden-signal-encryption-privacy-messaging/ |author= Dell Cameron |work= The Daily Dot |date= 6 March 2015 |access-date= 24 May 2015 |archive-date= 11 April 2015 |archive-url= https://web.archive.org/web/20150411022004/http://www.dailydot.com/politics/edward-snowden-signal-encryption-privacy-messaging/ |url-status= live }}</ref>

<ref name="theguardian-snowden">{{cite news |title= NSA surveillance powers on the brink as pressure mounts on Senate bill – as it happened |url= https://www.theguardian.com/us-news/live/2015/may/21/nsa-surveillance-rand-paul-senate-live |newspaper= The Guardian |author= Alan Yuhas |date= 21 May 2015 |access-date= 24 May 2015 |archive-date= 24 May 2015 |archive-url= https://web.archive.org/web/20150524115405/http://www.theguardian.com/us-news/live/2015/may/21/nsa-surveillance-rand-paul-senate-live |url-status= live }}</ref>

<ref name="voxmedia-snowden">{{cite web |title= The 9 best moments from Edward Snowden's Reddit Q&A |url= https://www.vox.com/2015/5/21/8638251/snowden-reddit |publisher= Vox Media |author= Zack Beauchamp |date= 21 May 2015 |access-date= 24 May 2015 |archive-date= 24 May 2015 |archive-url= https://web.archive.org/web/20150524033953/http://www.vox.com/2015/5/21/8638251/snowden-reddit |url-status= live }}</ref>

<ref name="eff1">{{cite web | url = https://www.eff.org/pages/secure-messaging-scorecard | publisher = Electronic Frontier Foundation | title = Secure Messaging Scorecard. Which apps and tools actually keep your messages safe? | date = 4 November 2014 | access-date = 14 January 2015 | archive-date = 15 November 2016 | archive-url = https://web.archive.org/web/20161115054343/https://www.eff.org/secure-messaging-scorecard | url-status = live }}</ref>

<ref name="motherboard1">{{cite web |url=https://www.vice.com/en/article/textsecure-is-the-easiest-encryption-app-to-use-so-far/ |title=TextSecure Is the Easiest Encryption App To Use (So Far) |author=DJ Pangburn |date=3 March 2014 |publisher=Motherboard |access-date=14 March 2014 |url-status=live |archive-url=https://web.archive.org/web/20140314165046/http://motherboard.vice.com/blog/textsecure-is-the-easiest-encryption-app-to-use-so-far |archive-date=14 March 2014 }}</ref>

<ref name="nyt1">{{cite news |url=https://www.nytimes.com/2014/02/20/technology/personaltech/privacy-please-tools-to-shield-your-smartphone-from-snoopers.html |title=Privacy Please: Tools to Shield Your Smartphone |author=Molly Wood |date=19 February 2014 |newspaper=The New York Times |access-date=26 February 2014 |archive-date=25 February 2014 |archive-url=https://web.archive.org/web/20140225120608/http://www.nytimes.com/2014/02/20/technology/personaltech/privacy-please-tools-to-shield-your-smartphone-from-snoopers.html |url-status=live }}</ref>

<ref name="techcrunch1">{{cite news|url=https://techcrunch.com/2014/11/18/end-to-end-for-everyone/|title=WhatsApp Partners With Open Whisper Systems To End-To-End Encrypt Billions Of Messages A Day|work=TechCrunch|author=Jon Evans|date=18 November 2014|access-date=19 November 2014|archive-date=18 November 2014|archive-url=https://web.archive.org/web/20141118220338/http://techcrunch.com/2014/11/18/end-to-end-for-everyone/|url-status=live}}</ref>

<ref name="pressfreedomfoundation">{{cite web |url= https://freedom.press/crowdfunding/signal/ |title= Signal |publisher= Freedom of the Press Foundation |access-date= 25 January 2017 |archive-date= 20 March 2018 |archive-url= https://web.archive.org/web/20180320152018/https://freedom.press/crowdfunding/signal/ |url-status= live }}</ref>

<ref name="ghacks1">{{cite web |url=http://www.ghacks.net/2014/02/24/textsecure-open-source-messaging-app-strong-security-features/ |title=TextSecure is an open source messaging app with strong security features |author=Martin Brinkmann |author-link=Martin Brinkmann |date=24 February 2014 |publisher=Ghacks Technology News |access-date=26 February 2014 |archive-date=2 March 2014 |archive-url=https://web.archive.org/web/20140302041935/http://www.ghacks.net/2014/02/24/textsecure-open-source-messaging-app-strong-security-features/ |url-status=live }}</ref>

<ref name="knightfoundation">{{cite web|title=TextSecure|url=http://www.knightfoundation.org/grants/201499909/|publisher=Knight Foundation|access-date=17 October 2016|archive-date=9 January 2021|archive-url=https://web.archive.org/web/20210109161315/https://knightfoundation.org/grants/201499909/|url-status=live}}</ref>

<ref name="shuttleworthfoundation">{{cite web|title=Moxie Marlinspike|date=September 2013|url=https://www.shuttleworthfoundation.org/fellows/moxie-marlinspike/|publisher=Shuttleworth Foundation|access-date=28 January 2017|archive-date=18 January 2015|archive-url=https://web.archive.org/web/20150118142900/https://www.shuttleworthfoundation.org/fellows/moxie-marlinspike/|url-status=live}}</ref>

<ref name="opentechfund">{{cite web |title=Open Whisper Systems |url=https://www.opentechfund.org/project/open-whisper-systems |publisher=Open Technology Fund |access-date=4 September 2017 |archive-date=21 May 2015 |archive-url=https://web.archive.org/web/20150521181458/https://www.opentechfund.org/project/open-whisper-systems |url-status=live }}</ref>

<ref name="fortune1">{{cite magazine |url=https://fortune.com/2014/11/18/facebooks-messaging-service-whatsapp-gets-a-security-boost/ |title=Facebook's messaging service WhatsApp gets a security boost |date=18 November 2014 |access-date=21 November 2014 |magazine=Forbes |archive-date=20 November 2014 |archive-url=https://web.archive.org/web/20141120193716/http://fortune.com/2014/11/18/facebooks-messaging-service-whatsapp-gets-a-security-boost/ |url-status=live }}</ref>

<ref name="techcrunch2">{{cite web|url=https://techcrunch.com/2014/07/29/talk-private-to-me-free-worldwide-encrypted-voice-calls-with-signal/|title=Talk Private To Me: Free, Worldwide, Encrypted Voice Calls With Signal For iPhone|publisher=AOL|work=TechCrunch|author=Jon Evans|date=29 July 2014|access-date=25 June 2017|archive-date=4 June 2016|archive-url=https://web.archive.org/web/20160604000058/http://techcrunch.com/2014/07/29/talk-private-to-me-free-worldwide-encrypted-voice-calls-with-signal/|url-status=live}}</ref>

<ref name="threatpost1">{{cite web|url=http://threatpost.com/new-signal-app-brings-encrypted-calling-to-iphone/107491|title=New Signal App Brings Encrypted Calling to iPhone|publisher=Threatpost|author=Michael Mimoso|date=29 July 2014|access-date=14 January 2015|archive-date=18 January 2015|archive-url=https://web.archive.org/web/20150118143554/http://threatpost.com/new-signal-app-brings-encrypted-calling-to-iphone/107491|url-status=live}}</ref>

<ref name="welcome">{{cite news |url=https://whispersystems.org/blog/welcome/ |title=A New Home |publisher=Open Whisper Systems |date=21 January 2013 |access-date=1 March 2014 |archive-date=29 April 2013 |archive-url=https://web.archive.org/web/20130429181434/https://whispersystems.org/blog/welcome/ |url-status=live }}</ref>

<ref name="signal">{{cite web |date=29 July 2014 |url=https://whispersystems.org/blog/signal |title=Free, Worldwide, Encrypted Phone Calls for iPhone |publisher=Open Whisper Systems |access-date=29 July 2014 |archive-date=29 July 2014 |archive-url=https://web.archive.org/web/20140729235000/https://whispersystems.org/blog/signal/ |url-status=live }}</ref>

<ref name="the-new-textsecure">{{cite web |url= https://whispersystems.org/blog/the-new-textsecure/ |title= The New TextSecure: Privacy Beyond SMS |author= Moxie Marlinspike |date= 24 February 2014 |publisher= Open Whisper Systems |access-date= 26 February 2014 |archive-date= 24 February 2014 |archive-url= https://web.archive.org/web/20140224200749/https://whispersystems.org/blog/the-new-textsecure/ |url-status= live }}</ref>

<ref name="whatsapp">{{cite web | url=https://whispersystems.org/blog/whatsapp/ | title=Open Whisper Systems partners with WhatsApp to provide end-to-end encryption | publisher=Open Whisper Systems | date=18 November 2014 | access-date=18 November 2014 | archive-date=18 November 2014 | archive-url=https://web.archive.org/web/20141118161936/https://www.whispersystems.org/blog/whatsapp/ | url-status=live }}</ref>

<ref name="signal-ios-github">{{cite web |url=https://github.com/signalapp/Signal-iOS |title=Signal-iOS |author=Open Whisper Systems |website=GitHub |access-date=14 January 2015 |archive-date=2 March 2018 |archive-url=https://web.archive.org/web/20180302135328/https://github.com/signalapp/Signal-iOS |url-status=live }}</ref>

<ref name="signal-android-github">{{cite web |url=https://github.com/signalapp/Signal-Android |title=Signal-Android |author=Open Whisper Systems |website=GitHub |access-date=8 July 2016 |archive-date=21 February 2018 |archive-url=https://web.archive.org/web/20180221090336/https://github.com/signalapp/Signal-Android |url-status=live }}</ref>

<ref name="signal-desktop-github">{{cite web |url=https://github.com/signalapp/Signal-Desktop |title=Signal-Desktop |author=Open Whisper Systems |website=GitHub |access-date=8 July 2016 |archive-date=2 March 2018 |archive-url=https://web.archive.org/web/20180302135330/https://github.com/signalapp/Signal-Desktop |url-status=live }}</ref>

<ref name="textsecure">{{cite web |url=https://github.com/WhisperSystems/TextSecure/ |title=TextSecure |author=Open Whisper Systems |website=GitHub |access-date=26 February 2014 |archive-date=8 February 2015 |archive-url=https://web.archive.org/web/20150208095618/https://github.com/WhisperSystems/TextSecure/ |url-status=live }}</ref>

<ref name="Flock-GH">{{cite web |url=https://github.com/WhisperSystems/Flock |title=Flock |author=Open Whisper Systems |website=GitHub |access-date=4 October 2015 |archive-date=3 November 2015 |archive-url=https://web.archive.org/web/20151103141512/https://github.com/WhisperSystems/Flock |url-status=live }}</ref>

<ref name="RedPhone">{{cite web |archive-url=https://web.archive.org/web/20150905191050/https://github.com/WhisperSystems/RedPhone|archive-date=5 September 2015|url=https://github.com/WhisperSystems/RedPhone |title=RedPhone |author= Open Whisper Systems |website= GitHub |access-date=11 November 2015}}</ref>

<ref name="bithub-gh">{{cite web |url=https://github.com/WhisperSystems/BitHub |title=BitHub |author=Open Whisper Systems |website=GitHub |access-date=14 January 2015 |archive-date=27 December 2014 |archive-url=https://web.archive.org/web/20141227204347/https://github.com/WhisperSystems/Bithub |url-status=live }}</ref>

<ref name="Signal-Server">{{cite web |url=https://github.com/signalapp/Signal-Server |title=Signal-Server |author=Open Whisper Systems |website=GitHub |access-date=21 November 2016 |archive-date=20 March 2018 |archive-url=https://web.archive.org/web/20180320152029/https://github.com/signalapp/Signal-Server |url-status=live }}</ref>

}}

==Literature== * {{cite conference |first1 = Nik |last1=Unger |first2=Sergej |last2=Dechand |first3=Joseph |last3=Bonneau |first4=Sascha |last4=Fahl |first5= Henning |last5=Perl |first6=Ian Avrum |last6=Goldberg |first7= Matthew |last7= Smith |title = SoK: Secure Messaging |publisher = IEEE Computer Society's Technical Committee on Security and Privacy |conference = Proceedings of the 2015 IEEE Symposium on Security and Privacy |year = 2015 |pages = 232–249 |doi=10.1109/SP.2015.22 |url = http://ieee-security.org/TC/SP2015/papers-archived/6949a232.pdf}}

==External links== {{Commons category|Open Whisper Systems}} * {{official|https://whispersystems.org/}}

Category:Free and open-source software organizations