Biometrics Questions & Answers with Greg Johnson

Welcome to the second column. The goal of this column is to answer questions that do not pop up in mainstream biometrics FAQ sheets. Hopefully these will not only give you some information you don’t have, but also raise another question or two. Send those questions to me! Let’s start off with the favorite of the movie-watching set:

Q: What happens if someone cuts off my finger?

A: This often-asked question, though gruesome, could have relevance for the DoD. The first challenge for the bad guy would be to get your finger. Assuming he is willing to do what that would take, he would then have to apply your finger to a sensor that does not have a liveness check built in. Liveness checks look for things like pulse, heat, or electrical capacitance of live tissue to determine if it is a live finger. If it is not, the system will not allow access. He would also have to keep it from drying out and shriveling. In most DoD biometrics access applications, the biometric system is only one of several layers of security. Official stickers on cars, human guards, scrutiny from other employees, Common Access Cards, and PINs are other layers of security that ordinarily would prevent the severed finger from being a practical means of attack for the bad guy. But it could be a realistic scenario for a small percentage of DoD members. Picture a communications van full of classified network equipment on a battlefield. The position has been overrun by the enemy, and the U.S. soldiers that used biometrics for access to those critical systems are dead. We cannot allow the enemy to be able to defeat those biometric safeguards using the corpses of the soldiers. DoD Biometrics, in conjunction with other government agencies, is ensuring that any biometric system used in that type of scenario will have liveness checks and will be part of a layered security system. The severed finger may not be a realistic threat against most of us, but for some in DoD it could be real.

Q: I have heard the terms “Red Force biometrics” and “Blue Force biometrics” being used in DoD. What do they mean?

A: “Red Force biometrics” refers to systems used for vetting and identifying enemy combatants, detainees, or other foreign persons of interest to the United States. Their biometric data are collected and checked against existing databases to see if they have been encountered before. “Blue Force biometrics” refers to using biometrics for vetting and verifying DoD military, civilian and contractor personnel. Fingerprinting a suspected terrorist would be Red Force biometrics. Use of a biometric credential by a U.S. Navy sailor would be Blue Force biometrics.

Q: Does iris recognition work better than fingerprint scanning?

A: There is no simple answer to this one. It's sort of like asking, “which is better, a car or a train?” Both biometric technologies claim uniqueness. Both are extremely accurate and quick. The costs are dependent on the size and type of the application. Each has advantages and disadvantages. Fingerprint technology can be used for vetting identities against existing databases and for controlling access to networks and buildings. Iris technology can be used in the same ways, but there currently are no large iris databases in existence for checking identities. Fingerprint technology can be used forensically, as latent fingerprints are often left at crime scenes. There is no latent iris image left at a scene. Iris access systems can be hands-free, however, making them suitable in some environments that are not practical for fingerprint systems. Within DoD, there are many situations in which personnel requiring controlled access are wearing gloves, such as medical environments, when wearing chemical suits, or simply in a cold climate. The bottom line is that the intended biometric application needs to be examined, and then the appropriate technology can be selected.

I hope this column has piqued your interest and can serve as a useful tool for continuing biometrics dialogue. Please send your questions to: BiometricsQ&A@dodbfc.army.mil. Include your office or organization in your email. Thanks for reading.

(Views expressed in this column are not necessarily endorsed by the Department of Defense. The goal of this column is to provide open forum for dialogue within the biometrics community.)