Rejoice, O lovers of privacy! For Open WhisperSystems has released Signal for iPhone , which gives any and every iPhone wielder the power to fully encrypt their calls against prying ears — and is completely compatible with OWS’s time-tested and well-liked RedPhone for Android . Under the hood, Signal uses push notifications to initiate calls, Amazon Web Services to route the data, and the ZRTP protocol, developed by Phil Zimmerman , to encrypt conversations end-to-end. You don’t need a new password or a new number; it’s built to Just Work TM . Oh, and your call’s metadata is protected/discarded as well.
The code is open-source and has an interesting contributor funding model , too; every merged pull request is rewarded with some of the Bitcoin donated to the project as a whole. The Open WhisperSystems iOS team — security researcher Frederic Jacobs and astrophysicist / hacker / engineer Christine Corbett (disclaimer/disclosure; Christine’s a friend) — are also working on encrypted text communications compatible with OWS’s TextSecure for Android, and expect to release that as part of a new version of Signal later this summer. At that point, on the Android side, RedPhone and TextSecure will similarly be rolled into a unified Signal app for Android. Development is also under way on browser extensions so you can make secure calls from your computer. One quirk of ZRTP’s anti-surveillance arsenal: to protect against Man-in-the-Middle attacks , it generates a random pair of words for each conversation — “hockey publisher” in the screenshot above. Users can ensure their word pairs match by simply reciting them to one another. If they don’t match , it’s a sign of a Man in the Middle. It’s been a busy summer for Open WhisperSystems. A month ago they won a $416,000 grant from the Knight Foundation , and last week they also released Flock , a private — and, of course, highly secure — cloud-sync service for Android calendars and contacts.
