Edward Snowden has helped design a mobile phone case called the "introspection engine" that, he claims, will show when a smartphone is transmitting information that could be monitored.
Presenting via video link to event at the MIT Media Lab in Cambridge, Massachusetts, Snowden and co-designer Andrew "Bunnie" Huang showed how the device connects to a phone's different radio transmitters, showing its owner knows when a cellular1, Wi-Fi or Bluetooth connection is being used to share or receive data.
Initial2 mockups of the introspection engine show a small, monochromatic3 display built into its casing shows whether the phone is "dark", or whether it is transmitting, and it also can supply an iPhone with extra battery power and cover the rear-facing camera.
It could be developed to act as a sort of "kill switch" that would disconnect a phone's power supply when it detects that a radio is transmitting data after its owner has attempted to turn it off.
The device is an academic project and nowhere near ready for the mass market, but could still influence how consumers view the "tracking devices" - otherwise known as smartphones that they rely on every day.
"-If you have a phone in your pocket that's turned on, a long-lived record of your movements has been created," Snowden said. "As a result of the way the cell network functions your device is constantly shouting into the air by means of radio signals a unique identity that validates4 you to the phone company. And this unique identity is not only saved by that phone company, but it can also be observed as it travels over the air by independent, even more dangerous third parties."