https://www.kickstarter.com/projects/620001568/jackpair-safe...
It's an end-to-end voice encryption device using Diffie-Hellman protocol for completely-distributed key exchange, so the keys never leave the box and there's no way we can hand over any key, or traffic, to the authorities.
The user interface of JackPair is minimal; it's connected with any phone and headset through standard 3.5 mm audio jack. All you need to do is to press the button on it to set up secure line over established phone calls. It's zero configuration with no software to install, no service subscription, and it works with any phone you already have.