Biometric authentication process consists of several stages, like measurement, signal processing, pattern matching & decision making. Measurement involves sensing biometric characteristics and is necessary both for the creation of the reference model and for each authentication trial.
The whole process works by comparing two sets of data. The first one is preset by the owner of the device, while the second one belongs to a device visitor. If the two data are nearly identical, the device knows that “visitor” & “owner” are one & the same and gives access to the visitor. More details on how biometric system works can please be referred.
The important thing to note is that the match between the two data sets has to be nearly identical but not exactly identical. This is because it is almost impossible for 2 biometric data to match 100%. For instance, there can be a small scar on finger & that can change the print pattern. In a typical biometric system two types of errors can happen
1) False Reject (FR) Error : Rejection of an authorized person who is trying to access the system.
2) False Accept (FA) Error : Acceptance of a person who is not one he or she claims to be.
These errors can be controlled by a confidence threshold. Increase of this threshold can increase the security of the system hence minimize the FA errors & increase the FR errors.
Advantages of biometric system:
1) Ease of use : A fingerprint or an iris scan is easier to use than a password & it takes a second for a device to recogniz e a physical characteristics.
2) Improved security : I augments the security level to allow a visitor an access.
3) Cannot be forgotten : As it depends on physical characteristics so chance of forgetting is overruled that may happen in case of a password.
4) Less operational cost : Including electricity the biometrics require very low operational cost.
Disadvantages of biometric system:
1) Biometrics last a lifetime : Physical characteristics cannot be modified. Passwords can be changed but biometrics cannot be reset once cvompromised.
2) Environment & usage can affect measurements : A damage in physical attributes can change the pattern that allows the access.
3) Requires integration : To record the data additional hardware integration is mandatory.
4) Master fingerprint can trick the device : Small devices need partial matches of physical attributes. For these cases 5 master fingerprints can be exploited to compromise the device security.
