With America on full alert for the foreseeable future, interest in biometric scanners -- devices that verify a person's identity by measuring unique features such as nasal curvature, iris patterns, or hand shape -- has been booming. But civil liberties watchdogs, privacy advocates, and even some security gurus warn that the devices are less effective than advertised and that the personal data they generate could easily be misused.
Currently, biometric tools are primarily marketed as "smart locks" to prevent trespassers from… more