Here’s some great news for the iPhone users who have a healthy level of concern about their call privacy. Open Whisper Systems, the company behind the secure RedPhone app for Android, and TextSecure (the encrypted text messaging app) have released an open source iPhone app for end-t0-end call encryption. It’s called Signal, and it’s fully compatible with RedPhone on Android, so calls between the two platforms can be secured.

Open Whisper Systems has excellent plans for Signal. Here’s what they had to say on their blog post about it:

Signal will be a unified private voice and text communication platform for iPhone, Android, and the browser. Later this summer, Signal for iPhone will be expanded to support text communication compatible with TextSecure for Android. Shortly after, both TextSecure and RedPhone for Android will be combined into a unified Signal app on Android as well. Simultaneously, browser extension development is already under way.

Signal (and RedPhone) use ZRTP, a well-tested protocol for secure voice communication. Because this ZRTP implementation is within an open source application it makes it easy for the general public to ensure two important requirements for any decent encryption system:

  1. That there are no Government (or otherwise) back doors hard coded into it
  2. That the implementation is legitimate and secure. One issue with all encryption systems is that if they are implemented incorrectly, it can leave the system vulnerable to known and unknown forms of attack. When companies keep their code proprietary, there’s no way to really know if they have gone about things in the best way, or if they inadvertently left gapping holes in their so-called “secure” system. Open source code goes a long way to minimising these kinds of issues.

Give it a try

You can install the app from iTunes, here.