Edward Snowden's phone case will tell you if you're being tracked

Edward Snowden stepped into the world of product design Thursday as he unveiled a concept for a new phone case that can detect when the device's radio is transmitting.

He presented the design for the case, which wires into the iPhone's interior workings via the SIM slot to monitor electrical signals sent to its internal antennas, at the MIT Media Lab's Forbidden Research event with hardware hacker Andrew "Bunnie" Huang. 

The new case, which is still at concept stage, is designed for front-line journalists who wish to conceal their location. However, Snowden hopes the device will eventually serve another purpose: exposing hidden government surveillance of smartphones.

The pair laid out the thinking behind their work in an accompanying document. "Unfortunately, journalists can be betrayed by their own tools," they wrote. "Their smartphones are also the perfect tracking devices."

"Because of the precedent set by the U.S.’s 'third-party doctrine,' which holds that metadata on such signals enjoys no meaningful legal protection, governments and powerful political institutions are gaining access to comprehensive records of phone emissions unwittingly broadcast by device owners. This leaves journalists, activists, and rights workers in a position of vulnerability."

The case aims to let journalists know when their phones are tracking or disclosing their location when they're supposed to be in airplane mode. The "introspection engine" will be an "open source, user-inspectable and field-verifiable module," they say.

A fair amount of work has gone into the design. The pair visited electronics market in Shenzhen, China, to collect spare parts and blueprints for the iPhone 6, which they used to reverse engineer the design.

They've identified several radio interfaces - cellular modem, Wi-Fi, GPS and NFC - and have focussed on these areas over things like the barometer, microphone and camera. A later design might include the option to obscure the camera physically, they say. If the case detects any unexpected radio transmission an alarm or pop up message would occur.

They explain how they created the product in great detail in the document.Mashable has reached out to Apple for comment on the case.

The case could be invaluable for journalists in sensitive areas such as Iraq or Syria, Huang told Wired.

“Our approach is: state-level adversaries are powerful, assume the phone is compromised," he said. "Let’s look at hardware-related signals that are extremely difficult to fake. We want to give a you-bet-your-life assurance that the phone actually has its radios off when it says it does.”

“One good journalist in the right place at the right time can change history,” Snowden said at the event via video stream. “This makes them a target, and increasingly tools of their trade are being used against them.”

Snowden told Wired he hasn't used a smartphone since 2013 for fear of being tracked. They're "kind of like kryptonite to me," he said.