The spy agencies of at least Europe and the U.S. (but also likely China), have tools that allow them to take over smartphones with just a text message, and according to Edward Snowden. He added that there is “very little” that their owners can do to stop it.

The control comes packed in a covert text message, which gains access to the phone but wouldn’t be visible to its user: you have no idea that it had arrived, Snowden said.

“That’s a specially crafted message that’s texted to your number like any other text message but when it arrives at your phone it’s hidden from you,” Snowden said. “It doesn’t display. You paid for it [the phone] but whoever controls the software owns the phone.”

Snowden reported doesn’t trust any smartphones, not dismisses Apple phones iPhones as a solution because: “The iPhone has special software that can activate itself without the owner having to press a button and gather information about him.” It is unclear if there exist any current smartphone models that are not susceptible to this.

In a turn for the strange, the UK’s intelligence agency has a toolset based on Smurfs that lets it listen on phones and their owners, Snowden told the BBC’s Panorama in Moscow. All agents would need to do is send a special text message in order to gain access to the camera and its microphones, the BBC reported Snowden as saying.

The set of tools is called “Smurf Suite”, and each of the individual tools has their own name — “Dreamy Smurf” lets the phone be powered on and off,  and “Nosey Smurf” lets spies turn the microphone on and listen in on users, even if the phone itself has been turned off.

GCHQ even has a tool called “Paranoid Smurf,” which hides the fact that it has taken control of the phone. The tool stops people from recognising that the phone has been hacked if it is taken in for a service, for instance.

Snowden said that GCHQ’s counterpart in the US, the NSA, has spent $1 billion on similar tools. It is likely that much more money has been funneled into this programs, and certainly more than a billion has spent on this effort if we include other related programs like voice and face recognition.