Tuesday saw the release of a new encrypted phone app for the iPhone. Signal, released by open source software group Open Whisper Systems, allows users to make secure calls on the iPhone at no cost.
Using end-to-end encryption, Signal secures iPhone conversations so third-parties cannot listen in. Signal uses a caller’s standard phone number to make and receive calls, and all Signal calls function like a normal phone call using WiFi or data connections.
According to Open Whisper Systems, Signal uses ZRTP, a secure voice communications protocol. The app uses push notifications to alert users when they receive a call to save on battery life. The app is open source software, so anyone is allowed to improve the code and contribute to the project.
To setup Signal, users merely enter their phone number, and then confirm it by entering a six-digit code, sent by SMS or a phone call, to begin using the app.
While contacts are automatically imported into the app, only those contacts using Signal will be listed. If you place a call to a contact who does not have Signal installed on their iPhone, you will be prompted to send them an invite via SMS.
When placing a call via Signal, both parties can rest assured that their call is secure via a pair of words shown on the screens of both parties. The two users then exchange the on-screen words to verify their words match, indicating that a secure connection has been made. If anyone is listening in on the call, the two words would not match, indicating the call had been breached.
Open Whisper Systems founder Moxie Marlinspike told Wired that the team’s goal was to make it as easy to place a secure call as it is to place a regular call. He said encrypted text messages will be added to the app in the future.
Signal is compatible with Open Whisper Systems’ RedPhone app for Android, allowing iOS and Android users to make secure calls to each other.
Signal is available FREE for the iPhone in the App Store. [DIRECT LINK]