Haven turns any spare android phone into a safe room that fits in your pocket,” claims NSA whistleblower Edward Snowden, referring to the newly-launched app that he developed, backed by the Freedom of Press Foundation. In an age where our digital security is at more risk than our physical security, Snowden claims that Haven will change the game of cyber surveillance.

Here’s how it works: once you install the app, it uses the smartphone’s in-built equipment, like cameras, light sensor and microphones, to monitor for any motion, sound or disturbance of the phone. As explained by WIRED: “Leave the app running in your hotel room, for instance, and it can capture photos and audio of anyone entering the room while you’re out, whether an innocent housekeeper or an intelligence agent trying to use his alone time with your laptop to install spyware on it.” Alerts can be sent to your phone, via SMS, Signal or to a Tor-based website.

Snowden and his team released the app as an open-source project to which people can contribute their money or skills. “You shouldn’t have to be saving the world to benefit from Haven,” said Snowden, though the app’s primary users are meant to be investigative journalists, human rights defenders, and other people at risk of forced disappearance.