In the wake of the terrorist attacks of September 11th 2001, however, these objections have been swept aside. After all, if you are already being forced to remove your shoes at the airport, and submit your laptop for explosives testing, surely you will not object to having your fingers scanned too? The desire to tighten security in every way possible, particularly in America, also means the funds are being made available to deploy technology that was previously regarded as too expensive to bother with.

As a result, biometrics are suddenly about to become far more widespread. America will begin using biometrics at its airports and seaports on January 5th. Under the new US-VISIT programme, all foreigners entering on visas will have their hands and faces digitally scanned. This will create what Tom Ridge, America's homeland-security supremo, calls “an electronic check-in and check-out system for foreign nationals”. American citizens will also be affected, as new passports with a chip that contains biometric data are issued from next year. And the new rules specify that by October 26th 2004, all countries whose nationals can enter America without a visa—including western European countries, Japan and Australia—must begin issuing passports that contain biometric data too. Moves to create a European standard for biometric passports are already under way, and many other countries are following suit: Oman and the United Arab Emirates, among others, will begin issuing national identity cards containing biometrics next year. Britain's planned new national identity card will also include biometrics.

In other words, governments either do not believe that the costs of biometrics still outweigh any potential benefits or, more likely, fearing more terrorism they simply do not care. This could be an expensive choice. Recent reports from groups such as the General Accounting Office (GAO), the investigative arm of America's Congress, and America's National Academy of Science (NAS), point out that, while the political environment has changed, the technology has not. Biometrics still do not work well enough to be effective for many of the applications in which they are now being deployed.

Even John Siedlarz, who co-founded the International Biometrics Industry Association to promote the sale and use of the technology, says that “recent congressional requirements are premature in my view.” Despite this concern from industry experts, politicians are keen to push onwards, and not only in America. Otto Schily, Germany's interior minister, recently declared his support for increased use of biometrics, asking: “How else would you propose to improve security?” Similarly, America's Justice Department responded to a recent GAO report by saying that the government is in a hurry to deploy biometrics—so why couldn't the GAO just get on board? It is difficult to avoid the conclusion that the chief motivation for deploying biometrics is not so much to provide security, but to provide the appearance of security.

I am whoever I say I am?
The claim that biometrics are not ready for widespread application may seem puzzling, given the advances in computer technology. To understand the reservations of the experts, it is necessary to take a closer look at how biometrics work.

Biometrics can be used in two ways. The first is identification (“who is this person?”), in which a subject's identity is determined by comparing a measured biometric against a database of stored records—a one-to-many comparison. The second is verification (“is this person who he claims to be?”), which involves a one-to-one comparison between a measured biometric and one known to come from a particular person. All biometrics can be used for verification, but different kinds of biometric vary in the extent to which they can be used for identification. They also vary in cost, complexity and intrusiveness. So which biometrics have been chosen for the new passports, visas and identity cards, and why?

The oldest biometric is the one we use most frequently—a person's face. But while recognising faces is something that people can do easily, computers find it very difficult. Most computerised face-recognition systems work by building a template based on 30 or so “markers”—the positions of the edges of the eyes, the cheekbones, the base of the nose, and so on. These markers are chosen so that they are unaffected by expression or the presence of facial hair. Matching faces is then a matter of matching the templates.

However, the results of an American government test released in March cast doubt on the accuracy of face-recognition systems. The test, called the Face Recognition Vendor Test, used systems from ten leading firms and a database of 121,589 images of 37,437 people. None of the systems worked well in a formal identification mode when shown a face and asked to identify the subject; nor did they work well when trying to recognise a face surreptitiously. However, three of the systems could be used for verifying identity in a controlled environment, such as the booths used to take passport photos.

“Biometrics still do not work well enough for many applications in which they are being deployed”


Joseph Atick of Identix, a biometrics vendor based in Minnetonka, Minnesota that took part in the test, insists that the deployment of his company's system by customers such as the state of Colorado, which is using it to try to prevent individuals from obtaining multiple driving licences, attests to the viability of facial biometrics. But Joel Lisker, a biometrics consultant who has worked extensively with America's Transportation Security Administration (TSA), says face-recognition systems have yet to prove themselves. In the TSA's own tests, not a single wanted person was spotted.