Think Changing Your SIM Card Can Mask Who You Are? Think Again

Tech-savvy criminals try to evade being tracked by changing their cellphone's built-in ID code and by regularly dumping SIM cards. But engineers in Germany have discovered that the radio signal from every cellphone handset hides within it an unalterable digital fingerprint — potentially giving law enforcers a simple way of tracking the handset itself.

Developed by Jakob Hasse and colleagues at the Technical Univ. of Dresden the tracking method exploits the tiny variations in the quality of the various electronic components inside a phone.

When analogue signals are converted into digital phone ones, the stream of data each phone broadcasts to the local mast contains error patterns that are unique to that phone's peculiar mix of components. In tests on 13 handsets in their lab, the Dresden team were able to identify the source handset with an accuracy of 97.6 percent. (more)