On the design of forgiving biometric security systems

This work aims to highlight the fundamental issue surrounding biometric security systems: it's all very nice until a biometric is forged, but what do we do after that? Granted, biometric systems are by physical nature supposedly much harder to forge than other factors of authentication since biometrics on a human body are by right unique to the particular human person. Yet it is also due to this physical nature that makes it much more catastrophic when a forgery does occur, because it implies that this uniqueness has been forged as well, threatening the human individuality; and since crime has by convention relied on identifying suspects by biometric characteristics, loss of this biometric uniqueness has devastating consequences on the freedom and basic human rights of the victimized individual. This uniqueness forgery implication also raises the motivation on the adversary to forge since a successful forgery leads to much more impersonation situations when biometric systems are used i.e. physical presence at crime scenes, identi cation and access to security systems and premises, access to nancial accounts and hence the ability to use the victim's nances. Depending on the gains, a desperate highly motivated adversary may even resort to directly obtaining the victim's biometric parts by force e.g. severing the parts from the victim's body; this poses a risk and threat not just to the individual's uniqueness claim but also to personal safety and well being. One may then wonder if it is worth putting one's assets, property and safety into the hands of biometrics based systems when the consequences of biometric forgery far outweigh the consequences of system compromises when no biometrics are used.