Federal Office for Information Security (BSI)

Biometrics in electronic ID documents

Capturing fingerprints

If fingerprints are needed for a new ID document (such as an electronic passport), they are recorded directly during application in the registration office. Special fingerprint scanners are used for this procedure.

For fingerprint recording one must place a finger on the recording surface of the scanner. A software checks whether the finger is placed correctly on the recording surface. The finger should be situated in the middle of the plate.

When the finger is in position, a picture is taken automatically. To achieve the best possible quality of the fingerprint, this process is repeated three times. The three images are compared and their quality (sharpness of the image, number of comparison characteristics) are tested. The recording, which best matches the other two, is then stored.

If the quality of all three recordings is insufficient, fingerprints of other fingers are recorded.

If possible, the prints of both index fingers are stored on the ID document. If the finger is injured or missing or the quality of the images is not good enough, the thumbs can be used next. If these can not be used either, then the middle fingers follow, then the ring finger.

The little fingers are never recorded because they are not particularly well suited for fingerprint comparison.

If only one finger can be recorded from a single person the fingerprint is stored alone. If no fingerprints can be taken because of an injury that is not permanent, the application must be delayed or a temporary passport is issued.

If it is virtually impossible to record the fingerprints, because the fingertips are extremely worn down or fingers are not available, an electronic passport is issued without fingerprints.

No fingerprints are taken from children under the age of six years.