Conceptual rendering of a "battery case" style introspection engine, piggybacked on an iPhone6.
Conceptual rendering of a "battery case" style introspection engine, piggybacked on an iPhone6.

Whistleblower and former U.S. intelligence contractor Edward Snowden says he's working on a mobile phone case that would prevent users from being spied on.

The ex-National Security Agency analyst hopes the case for the iPhone 6 will prevent the phone from transmitting certain data, particularly the location of the user.

The case, which would not block cellphone signals, would stop the phone from transmitting GPS data even when the phone is in “airplane mode.” Currently an iPhone 6 continues to transmit GPS data even in airplane mode, and this is seen as a potential way for governments or hackers to remotely “turn on” a phone.

"Front-line journalists are high-value targets, and their enemies will spare no expense to silence them," Snowden wrote, describing the project in a paper submitted to the Massachusetts Institute of Technology's Media Lab on Thursday morning. "Unfortunately, journalists can be betrayed by their own tools. Their smartphones, an essential tool for communicating with sources and the outside world -- as well as for taking photos and authoring articles -- are also the perfect tracking device."

FILE - Former U.S. National Security Agency contra
FILE - Former U.S. National Security Agency contractor Edward Snowden.

The case, which slips over the bottom of the phone, connects to the SIM card port and monitors outbound data, is being co-developed with Andrew Huang, a Singapore-based American hacker. An alarm would be triggered, should the device detect an unwanted signal.

A prototype of the case is expected next year, but don’t expect it to be widely available.

"The project is run largely through volunteer efforts on a shoestring budget," Snowden and Huang wrote.

The U.S. government believes Snowden jeopardized America's security by leaking classified information while he was working as a contractor for the NSA in 2013. He is believed to be living in Moscow.