Edward Snowden thinks about phone security a lot more than the average person. And with good reason, as the world-famous whistleblower revealed methods of government data collection on phone calls, and even from his exile in Russia, still remains a major advocate for digital privacy.

Snowden, together with hacker Andrew "Bunnie" Huang, announced today at the MIT Media Lab a design for a case-like attachment to modify an iPhone, allowing you to monitor if and when the radio transmitters within the device are active. Huang is known among other things for reverse engineering parts of the original Xbox and security vulnerabilities in microSD cards.

Their device will offer security to reporters in high-risk locations

Snowden’s argument for the need for such a device is that consumer-side methods, such as turning off the radios via airplane mode, shutting off the phone entirely, or even sealing it within a Faraday cage are all not nearly secure enough when faced with a government-backed adversary. Snowden and Huang’s device is designed to offer an option for reporters and journalists traveling in areas that use high-level hacking methods to monitor devices, and where, they claim, governments can use exploits to trick you into thinking your phone is off while actually monitoring your conversations and locations. Snowden and Huang hope that their device will offer security to reporters in high-risk locations by preventing the monitoring or tracking of phones, and to ensure that reporters can definitively shut down radio connectivity but maintain use of the device.

The device, which Snowden and Huang are referring to as an "introspection engine," consists of an attachment to a modified iPhone that physically wires into the antennas inside the phone for GPS, Bluetooth, cellular connectivity, and Wi-Fi through the SIM card slot (moving the SIM card itself into the external pack). It then can directly monitor radio transmissions, alert users to any unauthorized output when the radios are meant to be off, and even offer a kill-switch to immediately shut off the device.

A final production model would be intended to be both open-source and open hardware

At this point in time, the design from Snowden and Huang has yet to move beyond the basic testing stage, with no prototype or product in the pipeline for now beyond a concept rendering. The two hope to be able to eventually produce a prototype, and eventually work with manufacturers in China to build modified devices to sell or distribute to reporters. A final production model would be intended to be both open-source and open hardware to allow users to ensure that the device hasn’t been compromised during the manufacturing process. Additionally, Huang does have some previous experience with hardware design, as seen in his open-source Novena laptop, making it more likely that the design does become an actual device one day.

Huang and Snowden’s complete research paper further describing the methodology behind the introspection engine can be found here.