Students who want to enter the University of Montreal’s Athletic Complex need more than just a conventional ID card—-their identities must be proved genuine by an electronic hand scanner. In some California housing estates, a key alone is insufficient to get someone in the door;his or her voiceprint must also be verified(确认). And soon customers at some Japanese banks will have to present their faces for scanning before they can enter the building and withdraw their moneys.

　　All of these are applications of biometrics, a fast-growing technology that involves the use of physical or biological characteristic to identify individuals. In use for more than a decade at some high security government institutions in the United States and Canada, biometrics is rapidly popping up in the everyday world.

　　Biometric security systems operate by storing a digitized record of some unique human feature. When a user wishes to enter or use the facility, the system scans the person’s corresponding characteristics and attempts to match them against those on record. Systems using fingerprints, hands, voices, eyes, and faces are already on the market. Others using typing patterns and even body smells are in various stages of development.

　　Fingerprints scanners are currently the most widely used type of biometric application, thanks to their growing use over the last 20 years by law-enforcement agencies. Sixteen American states now use biometric fingerprint verification systems to check that people claiming welfare payments are genuine. Politicians in Toronto have voted to do the same, with a testing project beginning next year.

　　Not surprisingly, biometrics raises difficult questions about privacy and the potential for abuse. Some worry that governments and industry will be tempted to use the technology to monitor individual behavior. “If someone used your fingerprints to match your health-insurance records with credit-card record showing that you regularly bought lots of cigarettes and fatty foods,” says one policy analyst, “you would see your insurance payments go through the roof.” In Toronto, critics of the welfare fingerprint plan complained that it would force people to submit to a procedure widely identified with criminals.

　　Nevertheless, support for biometrics is growing in Toronto as it is in many other communities. In an increasingly crowded and complicated world, biometrics may well be a technology whose time has come.