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Saturday, August 9, 2008

What is BIOMETRICS - Tech Focus

Biometrics refers to the automatic identification of human beings based on their physical and/or behavioral characteristics (Bio = life + Metrics = measurement).These characteristics present some specific properties such as, uniqueness and persistency, making them suitable for this kind of task.

Examples of physical characteristics include among others: fingerprints, face, iris, retina, and hand geometry. On the other hand, examples of behavioral characteristics include: signature, voice, keystroke dynamics, etc.

Traditionally, authentication methods are divided into three main groups:
1. Tokens (What You Have)
The user possesses a physical and portable device which contains the users identity. Examples of such devices include bankcards, driver's licenses, passports, etc.

2. Passwords (What You Know)
These methods are based on a user's knowledge characterized by its secrecy. Examples include passwords, PINs, etc.

3. Biometrics (What You Are)
The user submits to the system his physical and/or behavioral characteristics. As a result, the individual is either accepted as a valid user or is rejected.Furthermore, an automated biometric system may opperate in two different modes: recognition and identification. In the former mode, the system authenticates a claimed identity by comparing an input biometric characteristic with its theoretical corresponding template. In the latter, the system does not receive a claimed identity and searches therefore an entire database for a match.

Advantages & Disadvantages

Since biometric characteristics cannot be guessed or stolen, biometric systems offer a higher degree of security than typical authentication methods (passwords or tokens).Efficient passwords are traditionally characterized by a long and alternated sequence of numbers and symbols. Therefore, they are sometimes difficult to remember.

Tokens, on their hand, may be stolen or loosed. Regardless of their authentication type, passwords or tokens can be shared. In this sense, there is no certainty of who is the actual user. Since biometric characteristics are not shared, this shortcoming is almost solved.

One important benefit of using biometric-based authentication systems is that they are able to keep track of the user's activities, e.g. it is possible to know who has been doing what at a given time (when). These benefits are not available in traditional authentication systems, since users may share their identification cues, being not possible, for example, to know who is the actual user.

Biometrics systems are convenient in environments where access privileges are necessary. Traditionally, in many authentication environments, a user may have different tokens or passwords. In these cases, biometrics can be used to simplify the authentication process since the multiple passwords or tokens can be replaced by a single biometric characteristics.Furthermore, another benefit is that biometric systems are easily scalable. Depending on the security level desired, more sophisticated biometric characteristics could be used. At a bottom level, one could use for example, characteristics that are not very discriminative. If more discriminable properties are desired in the system, biometric characteristics with higher distinctive properties may be used.

Hybrid Authentication
By considering that each biometric characteristic presents its own limitations, there have been some efforts to deal with these shortcomings. Multimodal biometric systems appear in this sense as an attractive solution. In this kind of systems, some biometric characteristics are used together to either verify or identify an individual. Therefore, multimodal biometric systems are expected to be more reliable than biometric systems based on just one single biometric characteristic.

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