A used phone can look convincing on the outside while leaving a buyer uncertain about what is inside. Federal researchers are studying whether the radio signals devices emit can help specialists recognize hardware changes, work that could eventually strengthen testing of phones and other wireless equipment.

In an Oct. 21 account, National Institute of Standards and Technology researchers described radio-frequency fingerprinting. The method examines electromagnetic signals from a device, rather than relying only on its appearance. One possible use is identifying equipment whose original components have been replaced with different parts without the buyer's knowledge.

The researchers reported more than 95 percent accuracy in their measurements using 16 devices from different manufacturers and models. That result belongs to the laboratory work described. It should not be interpreted as a guarantee that a consumer can identify 95 percent of altered phones with a downloadable application….READ MORE…