Signal has a sterling reputation within the security and crypto community, but its critics point to a nagging flaw: The app asks for access to your phone’s contact list when you install it. Signal’s creators, like the developers of so many other social apps, consider that contact-sharing request a necessary evil, designed to make the app as easy to use as your normal calling and texting features. But it’s one that some of Signal’s most sensitive users resent as a breach of its privacy promises.
Now Open Whisper Systems, the non-profit behind Signal, is launching an experimental new method to sew up that gap in its data protections, while still letting you flip through your existing address book to make encrypted calls and send encrypted texts. And the way they did it could serve as a model for other apps wrestling with the same address book privacy problem.