Researchers say they have created a special kind of paint which can block out wireless signals.
It means security-conscious wireless users could block their neighbours from being able to access their home network – without having to set up encryption.
The paint contains an aluminium-iron oxide which resonates at the same frequency as wi-fi — or other radio waves — meaning the airborne data is absorbed and blocked.
By coating an entire room, signals can’t get in and, crucially, can’t get out.