Open Whisper Systems, the group behind the Signal secure communication application for Android, this week announced the release of their encrypted messaging application for desktop computers.
The new Signal Desktop software is now available in beta as a Chrome application, designed to constantly stay connected with a phone, so that all incoming and outgoing messages are available on all devices at all time. The same as the Signal app for Android and iOS devices, Signal Desktop offers end-to-end encryption, offering support for free private group, text, picture, and video messages.
Once enabled, Signal Desktop enables users to seamlessly continue conversations back and forth between their mobile devices and a desktop computer, as all messages will be available instantly when switching to another device. Signal Desktop beta comes only with support for linking to the Android application, with iOS support expected to follow.
In addition to offering their end-to-end encryption messaging service for free, Open Whisper Systems has made the source code for Signal Desktop available for free as well, on GitHub. According to a blog post authored by security researcher Moxie Marlinspike earlier this week, the code was released so that experts could verify protocols and implementations.
The Signal application for Android and iOS devices provides users with both call and messaging encryption. Initially, Open Whisper Systems launched two different applications for Android, namely TextSecure and RedPhone, but they decided to merge them into a single program, and managed to do so earlier this year.
Signal uses the ZRTP protocol for communication encryption, a security protocol invented by Pretty Good Privacy creator Phil Zimmermann, who is also the co-founder of Silent Circle, a company focused on paid encrypted communication services.
Users do not need passwords when utilizing Signal, but are presented with a pair of words instead. The connection between the caller and the receiver is considered secure when the words match at both ends. If they do not match, the connection is insecure and chances are that someone is eavesdropping on the conversation.
Signal for iOS was released in summer last year, when Open Whisper Systems announced plans to merge TextSecure and RedPhone for Android into a single application. In November last year, the company partnered with Facebook-owned WhatsApp to offer end-to-end encryption (use TextSecure protocol) for the latter, using the TextSecure protocol for that.