[HT Bruce Schneier]
Here’s an excellent article on the use of biometrics in security system. Here are some highlights.
Authentication of a person is usually based on one of three things: something the person knows, such as a password; something physical the person possesses, like an actual key or token; or something about the person’s appearance or behaviour. Biometric authentication relies on the third approach. Its advantage is that, unlike a password or a token, it can work without active input from the user. That makes it both convenient and efficient: there is nothing to carry, forget or lose.
The downside is that biometric screening can also work without the user’s co-operation or even knowledge. Covert identification may be a boon when screening for terrorists or criminals, but it raises serious concerns for innocent individuals. Biometric identification can even invite violence. A motorist in Germany had a finger chopped off by thieves seeking to steal his exotic car, which used a fingerprint reader instead of a conventional door lock.
Another problem with biometrics is that the traits used for identification are not secret, but exposed for all and sundry to see. People leave fingerprints all over the place. Voices are recorded and faces photographed endlessly. Appearance and body language is captured on security cameras at every turn. Replacing misappropriated biometric traits is nowhere near as easy as issuing a replacement for a forgotten password or lost key. In addition, it is not all that difficult for impostors to subvert fingerprint readers and other biometric devices.
The panel of scientists, engineers and legal experts who carried out the study concludes that biometric recognition is not only “inherently fallible”, but also in dire need of some fundamental research on the biological underpinnings of human distinctiveness. The FBI and the Department of Homeland Security are paying for studies of better screening methods, but no one seems to be doing fundamental research on whether the physical or behavioural characteristics such technologies seek to measure are truly reliable, and how they change with age, disease, stress and other factors. None looks stable across all situations, says the report. The fear is that, without a proper understanding of the biology of the population being screened, installing biometric devices at borders, airports, banks and public buildings is more likely to lead to long queues, lots of false positives, and missed opportunities to catch terrorists or criminals.