A criminal or terrorist might steal an epassport and replace the picture by a fraudulent one on the printed data page, but there is a digital copy of your picture on the epassport security chip that cannot be changed without detection.

The information on the chip-including everything on the printed data page and the photograph-is "signed" using a type of electronic seal, called a digital signature. It is virtually impossible to counterfeit an epassport, because no one can duplicate the authentic digital seal on the electronic data that is created by the passport issuing authority. Furthermore, any change to the chip information breaks the seal, so tampering is evident to a border agent.

At passport control, border agents can compare the person, the paper passport and the signed information on the security chip. These all have to match to confirm the identity of the person presenting the passport. To tie the passport even more securely to its owner, the European Union and other countries are planning to store fingerprint biometrics in the chip. Germany already has fingerprint biometrics securely stored on the passport, and other EU countries are testing it.