We're going to use your toothbrush to snoop on you, says US spy boss

"Smart devices incorporated into the electric grid ... can threaten data privacy, data integrity, or continuity of services," he said. "In the future, intelligence services might use the IoT for identification, surveillance, monitoring, location tracking, and targeting for recruitment, or to gain access to networks or user credentials."

The data from IoT products can potentially be hugely valuable. Many include microphones and motion sensors, for example, such as new smart TVs, kids' toys and voice-controlled products like Amazon's Echo.