D3.10: Biometrics in identity management

Title: FORENSICS WITH BIOMETRIC METHODS

Forensics with biometric methods

In forensic science, biometrics has been used for a long time. The first textbook on the subject was authored by Sir Francis Galton in 1892. The French policeman Bertillon had developed a system of personal identification by bodily measurements. It became known as the Bertillon system. From about 1910, the fingerprint became more widely used, since it was easy to compare and store in comparison to the Bertillon system where many measurements had to be taken from each body part, with many errors possible.

Nowadays there exist large Automated Fingerprint Identification Systems (AFIS). The first automated systems where available in 1950 with punch cards which were mechanically searched. In the early 1970s, computer based systems were feasible for fingerprints. Nowadays the largest network of AFIS has over 25 million subjects in the database. Also palm prints are entered in a database. Barefoot soles, lip prints, ear prints are also examples of prints, but are not stored in such a centralised database.

Face comparison is also commonly done at police stations. The scientific background of face comparisons still should be validated. In forensic science, there are several efforts for making a face comparison more objective. Despite the face databases that are available, automated searching in these databases is not feasible without going through many false hits (the equal error rate is high, and with aging of a person this can be as high as 0.4-0.5, which means that one has to search through half of the database before finding the right person).

Iris systems and databases are described to be very effective. However, in forensic science, we do not often get cases with iris-comparisons. In National Geographic, one case is shown where a comparison of a photograph of an Afghan girl with the photograph of a woman gives evidence that they are the same person. The resolution of commonly made digital photographs is not enough to compare the irises. Commercial systems for iris comparison for access control are implemented in airports. The largest database of irises is reported to be in United Arab Emirates, where over half a million irises were in the database in 2005.

There exist many DNA databases for criminal cases. In the UK, approximately 4.2 million people or seven percent of the population is in the database in 2006. Compared to Germany and the USA, they only have DNA of 0.5 percent of the population. DNA data is easy to store and not expensive anymore to extract. The time to extract it is currently the limitation. In 2006, no commercial access control system existed based on DNA profile.

Handwriting is also commonly used in forensic science. It is used as evidence in forgery cases, kidnappings with ransom notes and many other crimes where handwriting is used. Document examiners also find much work in civil cases. Handwriting analysis is a field which covers lots of experience and training. The handwriting examiners have several groups and quality assurance models in order to have solid conclusions. Databases of handwriting are developed, however they are not in widespread use. Also commercial implementation of handwriting comparison exists in the field of biometrics.

For forensic science, also several other biometric features are used as evidence. Evidence such as nail marks (from fingernails), are more easily accepted in court.

The advantage of the databases of biometrics, such as fingerprints, irises, faces and many more, is that there exist a database and more information can be extracted from them based on statistics. The drawback is that the database should be filled in a standardised way, which in practice has been demonstrated to be an issue.