The Best Encrypted Chat App Now Does Video Calls Too – WIRED

Slide: 1 / of 2. Caption: Open Whisper Systems

Slide: 2 / of 2. Caption: Open Whisper Systems

Even as the encryption app Signal became the go-to private communications channel for activists, journalists, politicians, and more, its encrypted calling feature remained less than perfect. It lacks video, often drops calls, and doesnt always integrate with your phones existing features. A Signal update gradually rolling out now upgrades the calling features and adds video, toobut might require its most privacy-sensitive users to take an extra step to protect themselves.

On Tuesday, Signals creators at the non-profit Open Whisper Systems announced a beta version of the update that, in addition to video calling, adds the ability to answer calls from a locked screen, and what they promise will be better call quality. For now, anyone who receives the update can choose activate those new features in the advanced menu under Signals settings. We want Signal to be a joy to use, says Moxie Marlinspike, Open Whisper Systems founder. Were constantly focused on continuing to refine it and add features and functionality that we think people will love.

But anyone testing the beta who links their iPhone to iCloud and wants the same level of privacy Signal has always offered should consider an extra step, too: Disabling a setting that uploads a calls metadata to Apple. The beta upgrade to Signal will use CallKit, Apples framework for allowing VoIP calls like Signals, to be integrated more completely into the calling functionality of the phone. But that also means calls will be recorded in the iPhones call log and, for iCloud users, shared with Apples server. iOS treats CallKit calls like any other call, however that also means some information will be synced to iCloud if enabled, Open Whisper Systems warns. This information includes who you called and how long you talked.

For anyone who cringes at the thought of leaking that metadata, however, the new Signal beta will let you turn CallKit integration off on the same Advanced menu in the apps settings. CallKit integration will only be used if its enabled on both ends of the callif you disable it, your metadata wont be leaked by your contacts phone, either. And Open Whisper Systems is still considering whether the version of Signal it pushes out after this beta will integrate CallKit by default, or as an opt-in feature.

How we handle CallKit once this is the default experience isnt entirely resolved, Marlinspike says. He suggests that the app could mere display Signal users in the iPhones call log to protect users identities, or Signal may walk users through its settings when once installed, to help people choose their privacy preferences. There are a bunch of things we can do other than just having it on by default.

Signals popularity grew in part because it has long made certain privacy tradeoffs to make the app more usable. It integrates a phones existing contacts for convenience, for instance, but requires that a number be added to a phones contact list before it can be called. That means if the phone backs its contacts up to the cloud, some sensitive details could be leaked. And Signal has avoided a federation feature that would allow Signal users to set up their own server to communicate over, rather than use Signals more centralized system.

Aside from the CallKit change, Signal has also fully redesigned its VoIP protocol and reworked how it authenticates that bad actors arent surreptitiously impersonating users during calls. In the past, Signal has offered two unique words generated on the callers screens from their encryption keys. The callers each read out a word, and if they match, they can be sure no man-in-the-middle is eavesdropping on their call. In the new version, Signals voice and video calling will drop those word pairs and instead use the same authentication system as its text messaging feature, which depends instead on simply warning users if their contacts encryption key has suspiciously changed.

All of that means Signal is making the process of an encrypted call feel far more like making a normal one. The next time youre foiling the eavesdroppers trying to listen in on your secret conversations, in other words, you may not even notice.

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The Best Encrypted Chat App Now Does Video Calls Too - WIRED