Former NSA contractor Edward Snowden speaks via robot at a TED conference in Vancouver in March 2014. (Glenn Chapman/AFP via Getty Images)

Edward Snowden, the former NSA contractor who helped expose the extent of U.S. government surveillance, is among the most notorious and celebrated American fugitives. But from his self-imposed exile in Russia, he has also managed to establish himself as the most significant personal brand on privacy issues.

On Thursday, Snowden took the first step in using that brand to launch an actual product. During an MIT Media Lab presentation, Snowden and security researcher Andrew Huang unveiled plans for a phone case that could give activists and journalists a heads-up when their phone is secretly sending out signals that could enable them to be tracked by intelligence agencies.

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

The device, which looks like a external battery case, has a tiny screen that would tell a user if the phone is still sending out GPS, cellular, WiFi or Bluetooth signals when the device has been turned off. Snowden had warned in a 2014 NBC interview that some malware could make an iPhone appear to be switched off even when it's still sending out signals.

While Snowden lay low for a while after being granted asylum in Russia in 2013, he's become much more visible in the years since: joining up with Glenn Greenwald and Laura Poitras — journalists who helped publicize his NSA revelations — at the Freedom of the Press Foundation; live-streaming into panel discussions around the world — sometimes with the help of a robotic proxy; launching a Twitter account that now has well over 2 million followers; and endorsing privacy-related cyber-services, such as SpiderOak's cloud storage option and the encrypted messaging app Signal.

Snowden is also the subject of a biopic directed by Oliver Stone that was recently screened at Comic-Con and is expected to get a wide U.S. release in September — giving Snowden an aura of celebrity few privacy advocates have achieved.

His latest phone-case venture, which Snowden is working on as part of his role at the Freedom of the Press Foundation, is still in the design stage. Its very existence, however, suggests that Snowden is keen to use the brand he's been cultivating to push forward the international conversation about surveillance and privacy.