Pervasive services of virtual communities and digital governments are achievable only if trust, privacy and security can be secured and strengthened. To meet these requirements, mechanisms, which provide secure management of information and facilities without compromising privacy and civil rights, have to be devised. The success of such mechanisms relies on effective identity authentication. While traditional security measures such as PINs and passwords may be forgotten, stolen or cracked, biometrics provides authentication mechanisms based on unique human physiological and behavioral characteristics that can be used to identify an individual or authenticate the claimed identity of an individual, but cannot be easily duplicated or forged. Typical characteristics include but are not limited to fingerprint, face, iris, hand geometry, palm, voice pattern, signature, keystroke dynamics and so forth. Moreover, in the light of homeland security, biometrics has become a powerful measure in the government’s fight against identity fraud, illegal immigration, illegal workers and terrorism. Biometrics is also useful in preventing abuses of public health services and other government entitlement.