Whisper Systems

Whisper Systems was an American enterprise mobile-security company founded in 2010 by security researcher Moxie Marlinspike and roboticist Stuart Anderson. The company focused on protecting communications and data on Android devices, at a time when mobile operating systems and application ecosystems were becoming increasingly important to businesses, activists, and individual users. Its work combined encrypted communications with broader device-security controls rather than concentrating solely on a single messaging product. The company's best-known applications were TextSecure and RedPhone. TextSecure enabled end-to-end encrypted text messaging between compatible users, while RedPhone provided end-to-end encrypted voice calls over the internet. Whisper Systems also developed products intended to secure data stored on devices and in backups. Flashback was designed for encrypted cloud backups, and WhisperCore integrated security features into the Android operating system, including full-disk encryption, network-security functions, encrypted backup, selective permissions, and basic device-management capabilities. WhisperMonitor complemented WhisperCore with a software firewall, dynamic outbound-connection filtering, and real-time monitoring of application connections. Whisper Systems operated as a proprietary enterprise software company during its independent existence. On November 28, 2011, it announced that Twitter had acquired the company. The financial terms were not disclosed. Public reporting described the transaction as being driven primarily by Twitter's interest in having Marlinspike help strengthen the startup's security capabilities. The acquisition effectively ended Whisper Systems as an independent company and changed the availability of its products. After the acquisition, RedPhone was temporarily made unavailable. The decision drew criticism because the service was used by people in politically sensitive and repressive environments, including users affected by the 2011 Egyptian revolution. Twitter subsequently released TextSecure under the GNU General Public License version 3 in December 2011 and released RedPhone under the same license in July 2012. These releases allowed the software to continue outside Twitter and created the basis for later community-led development. Following his departure from Twitter, Marlinspike established Open Whisper Systems as a collaborative open-source project. The project continued development of the released software with volunteer contributors and a small grant-funded development team. In November 2015, TextSecure and RedPhone were combined and renamed Signal. Later organizational developments led to Signal Messenger LLC and the independent Signal Technology Foundation, which support the Signal service. Whisper Systems therefore no longer operates as an independent brand, but its products and the open-source code released after the Twitter acquisition were important predecessors to the modern Signal ecosystem.

Whisper Systems was established in 2010 by Moxie Marlinspike, a security researcher, and Stuart Anderson, a roboticist. It was organized as an enterprise mobile-security company and developed software for Android devices. Its product range reflected a broad view of mobile security: the company worked on encrypted communications, protection of locally stored information, secure backups, and controls over application network activity. TextSecure was the company's encrypted messaging application. It allowed users to exchange end-to-end encrypted SMS messages with other TextSecure users. RedPhone provided a corresponding encrypted voice-calling service using voice-over-IP connections. These applications addressed the confidentiality of communications, while other Whisper Systems products targeted the device itself. Flashback was intended to preserve encrypted backups in the cloud. WhisperCore integrated security functions with the Android operating system and, in its initial beta, included full-disk encryption, network-security tools, encrypted backup, selective permissions, and basic platform-management features for Nexus S and Nexus One devices. WhisperMonitor worked with WhisperCore as a software firewall, offering dynamic egress filtering and real-time observation of network connections. On November 28, 2011, Whisper Systems announced that Twitter had acquired it. Neither company disclosed the financial terms. The transaction was publicly characterized as being motivated mainly by Twitter's desire to have Marlinspike contribute to the security of the then-young social-media company. The acquisition ended Whisper Systems' independent corporate operation and altered access to its services. RedPhone was made unavailable soon afterward. The withdrawal attracted criticism because encrypted voice communication was particularly relevant to people operating under repressive governments, including Egyptians during the political unrest of 2011. The acquisition did not end the technical life of the products. Twitter released TextSecure under the GPLv3 open-source license in December 2011 and released RedPhone under the same license in July 2012. After leaving Twitter, Marlinspike created Open Whisper Systems, a collaborative project that continued work on the released code. It was supported by volunteer open-source contributors and a small group of grant-funded developers rather than continuing as the original commercial company. In November 2015, Open Whisper Systems combined TextSecure and RedPhone under the Signal name. Subsequent development of Signal took place through Signal Messenger LLC and the independent Signal Technology Foundation. As a result, Whisper Systems is now a defunct historical company and brand, while its software lineage continues through Signal. The company is significant less for its duration as an independent business than for the way its encrypted mobile products, open-source release, and post-acquisition community development contributed to the evolution of privacy-oriented communications software.

1. 2015The projects became Signal

   Open Whisper Systems merged TextSecure and RedPhone and renamed the combined service Signal.

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2. 2012RedPhone became open source

   Twitter released RedPhone under the GPLv3 license in July.

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3. 2011Twitter acquired Whisper Systems

   The acquisition was announced on November 28; its financial terms were not disclosed.

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4. 2011TextSecure became open source

   Twitter released TextSecure under the GPLv3 license.

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5. 2010Whisper Systems was founded

   Moxie Marlinspike and Stuart Anderson co-founded the mobile-security company.

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Privacy-focused mobile-security software combining encrypted communications with device, application, backup, and network protections.

• TextSecureEncrypted messaging

  TextSecure was an Android application for exchanging end-to-end encrypted SMS messages with other TextSecure users. It was one of Whisper Systems' principal communication products and was later released by Twitter under the GPLv3 license. Continued development outside Twitter ultimately contributed to the Signal messaging product.

• RedPhoneEncrypted voice communication

  RedPhone was an Android application that enabled end-to-end encrypted voice-over-IP calls between RedPhone users. The service was made unavailable shortly after Twitter acquired Whisper Systems, prompting criticism from users and observers concerned about the effects on people relying on secure communications. Twitter later released the software under the GPLv3 license.

• FlashbackEncrypted backup

  Flashback was designed to let users store encrypted backups of their mobile devices in the cloud. It extended Whisper Systems' security approach beyond live communications by addressing the protection of information held in backup storage.

• WhisperCoreAndroid device security

  WhisperCore integrated security features with the Android operating system. Its initial beta included full-disk encryption, network-security tools, encrypted backup, selective permissions, and basic platform-management capabilities for Nexus S and Nexus One devices. The product represented the company's broader enterprise-oriented device-protection strategy.

• WhisperMonitorMobile firewall and network monitoring

  WhisperMonitor worked with WhisperCore to provide a software firewall for Android devices. Its functions included dynamic egress filtering and real-time monitoring of network connections, giving users greater visibility into where data was sent and how applications communicated.

• 2015Merged TextSecure and RedPhone as SignalOther

  Open Whisper Systems was maintaining the open-source successors to Whisper Systems' messaging and calling products.

  What changed. In November 2015, Open Whisper Systems merged TextSecure with RedPhone and renamed the combined service Signal.

  Aftermath. Signal became the continuing product identity for the open-source communications work associated with the Whisper Systems lineage.

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• 2012Released RedPhone under an open-source licenseStrategy

  RedPhone had been made unavailable shortly after the Twitter acquisition, generating criticism from users concerned about the loss of encrypted calling.

  What changed. Twitter released RedPhone under the GPLv3 license in July 2012.

  Aftermath. The code became available for continued community development outside Twitter and later formed part of the lineage leading to Signal.

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• 2011Accepted Twitter's acquisitionM&A

  Whisper Systems was an independent mobile-security company whose products included encrypted messaging, encrypted calling, and Android security tools.

  What changed. The company announced on November 28, 2011 that Twitter had acquired it. The financial terms were not disclosed.

  Aftermath. Whisper Systems ceased operating independently. Moxie Marlinspike worked with Twitter on security, while the company's products subsequently underwent changes in availability and licensing.

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• 2011Released TextSecure under an open-source licenseStrategy

  After the acquisition, the future of Whisper Systems' software was determined within Twitter rather than by the original independent company.

  What changed. Twitter released TextSecure under the GPLv3 license in December 2011.

  Aftermath. The release enabled outside developers and the later Open Whisper Systems project to continue work on the software.

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• 2015TextSecure and RedPhone were combined as Signal

  Open Whisper Systems merged the messaging and calling projects and renamed the combined service Signal, establishing the direct product lineage from Whisper Systems to Signal.

  Product generationProduct launch
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• 2012Twitter released RedPhone as open source

  RedPhone was released under the GPLv3 license in July 2012, extending the open-source transition that followed the acquisition.

  Product launchOther
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• 2011Twitter acquired Whisper Systems

  Whisper Systems announced on November 28, 2011 that Twitter had acquired the company. The financial terms were not disclosed, and the stated rationale centered on Moxie Marlinspike helping Twitter improve its security.

  M&ALeadership change
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• 2011RedPhone became unavailable after the acquisition

  Shortly after Twitter acquired Whisper Systems, the RedPhone service was made unavailable. Critics objected that the change affected users who depended on encrypted communications in politically repressive settings.

  OtherRegulation
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• 2011Twitter released TextSecure as open source

  Twitter released TextSecure under the GPLv3 license, allowing its source code to be used and developed outside the original company.

  Product launchOther
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1. Whisper Systems