The free and open source encryption app, which was previously known as Redphone and TextSecure on Android, is now coming to desktops. Open Whisper Systems, the non-profit that develops the app, announced the release of the beta version of Signal for desktop on Wednesday.
"As always, everything is end-to-end encrypted and painstakingly engineered in order to keep your communication safe–allowing you to send high-quality private group, text, picture, and video messages for free," the announcement read.
Signal for desktop is an app for Chrome that links with the user's phone, and syncs messages between it and their computer. Having the chance to use Signal on the desktop offers several advantages. Other than the obvious one—the easier typing experience—Signal users will be able to switch between computer and cellphone seamlessly.
For now, the app is only in beta, and it's just for Android users. But if you use Signal on Android, you can sign up to request early access to the app here. Support for iOS users will come only at the time of the official launch, according to Frederic Jacobs, a developer at Open Whisper Systems.
For the users, everything happens in the background and there's no way of telling if you're communicating with someone on their desktop or their cellphone. The conversation is between people, not devices, according to Lilia Kai, a developer at Open Whisper Systems. Messages and contacts are sent between your devices using the same end-to-end encryption protocol, known as Axolotl.
"When you send a message to someone from Signal Desktop, a second copy of that message is encrypted and sent to your phone, and vice versa," Kai told Motherboard in an email. "The transition between mobile and desktop is seamless."
The app recently became cross-platform, so iPhone users can exchange messages with Android users. Signal is one of many encryption apps that have gained popularity in the last few years, especially in the wake of the Snowden revelations. But the key differentiator between Signal and some of its competitors such as Silent Circle is that it's completely free, and has received praise for being secure and extremely easy to use, not just from Snowden but also respected cryptography experts such as Matthew Green, an assistant professor at Johns Hopkins University.
"After reading [Signal's predecessor] RedPhone code the first time, I literally discovered a line of drool running down my face. It's really nice," Green once wrote.
Given that there aren't many options to chat securely using end-to-end encryption that are also easy to use on a desktop, the app has a chance to become even more popular and give internet users a good way to chat privately.
This article has been updated with more details on how Signal for desktop syncs with the mobile app.