National Security Agency whistleblower Edward Snowden continued his crusade against government surveillance on Thursday, revealing the design for an iPhone case that would safeguard the user’s location.
The device would alert the phone owner when its radio signals, which can broadcast location, were turned on. Snowden said that even when such features are supposedly disabled while turned to “airplane mode,” the government can use radio signals to track the phone.
“Turning off radios by entering airplane mode is no defense; for example, on iPhones since iOS 8.2, GPS is active in airplane mode,” Snowden wrote in a coauthored paper on the proposal. “Malware packages, peddled by hackers at a price accessible by private individuals, can activate radios without any indication from the user interface; trusting a phone that has been hacked to go into airplane mode is like trusting a drunk person to judge if they are sober enough to drive.”
Snowden and his research partner, Andrew Huang, introduced the invention at a Massachusetts Institute of Technology conference on Thursday, with the NSA whistleblower appearing remotely from Russia, where he remains exiled to avoid U.S. government espionage charges.
Snowden said the device was intended to prevent those doing sensitive work, like journalists and human rights workers, from having their locations monitored via their smartphones. The tool would be inside a phone-mounted battery case.
“We call this tool an introspection engine. The introspection engine has the capability to alert a reporter of a dangerous situation in real-time,” Snowden wrote. “The core principle is simple: if the reporter expects radios to be off, alert the user when they are turned on.”
Snowden and his partner said they hope to create a prototype of the device over the coming year, which they will seek to manufacture if it works as intended.