Edward Snowden doesn't like a world that has digital surveillance, and is trying to fight it.

It's been three years since he disclosed the NSA's convoluted espionage program. 

And now, with the help of Andrew "Bunnie" Huang, he is trying to go one step further. He is creating a design for an iPhone case that can check electrical signals that were transmitted to the smartphone's internal antennas. The attempt is to locate any "rogue signal" that is sent. 

At the MIT Media Lab, the design was disclosed, showing a "case-like device" accompanied by a "monochrome screen" and labelled the 'introspection engine.' It has a tiny probe that is part of iPhone's radio antennas, which can be approached through the SIM card slot. There are two antennae in the iPhone transmitting electronic signals and used by the GPS, Bluetooth, Wi-Fi and so on.

The signals being beamed by the antennae to flag the user while transmitting information is being probed. The user will be warned through messages as well as audible alarm. With this, the device can get shut off.

This protects scribes who do not need to be wary of being spied upon. 

"One good journalist in the right place at the right time can change history," Snowden told the MIT Media Lab crowd via video stream. "This makes them a target, and increasingly tools of their trade are being used against them."

Currently, the iPhone modification is just a design, but the anti-surveillance duo tested the way in which electrical signals can be sent to the phone's antennae and studied, in order to check various radio messages. 

A prototype will hopefully be out by next year. Snowden and Huang released their design through a video stream, examining the technique in detail. The aim is to start a supply chain of modified iPhones in China that can be offered to journalists globally.

Huang has said the code and the hardware design will be open-source.

Snowden's paper outlined a plan to Huang to make a modified phone that can protect scribes from government-sponsored opponents.