Impostor Access in Biometric Systems

B.

When the biometric system accepts impostors who should have been rejected , it is called a Type II error or False Acceptance Rate or False Accept Rate.

Biometrics verifies an individuals identity by analyzing a unique personal attribute or behavior, which is one of the most effective and accurate methods of verifying identification.

Biometrics is a very sophisticated technology; thus, it is much more expensive and complex than the other types of identity verification processes.

A biometric system can make authentication decisions based on an individuals behavior, as in signature dynamics, but these can change over time and possibly be forged.

Biometric systems that base authentication decisions on physical attributes (iris, retina, fingerprint) provide more accuracy, because physical attributes typically dont change much, absent some disfiguring injury, and are harder to impersonate.

When a biometric system rejects an authorized individual, it is called a Type I error (False Rejection Rate (FRR) or False Reject Rate (FRR))

When the system accepts impostors who should be rejected, it is called a Type II error (False Acceptance Rate (FAR) or False Accept Rate (FAR)).Type II errors are the most dangerous and thus the most important to avoid.

The goal is to obtain low numbers for each type of error, but When comparing different biometric systems, many different variables are used, but one of the most important metrics is the crossover error rate (CER)

The accuracy of any biometric method is measured in terms of Failed Acceptance Rate (FAR) and Failed Rejection Rate (FRR)

Both are expressed as percentages.

The FAR is the rate at which attempts by unauthorized users are incorrectly accepted as valid.

The FRR is just the opposite.

It measures the rate at which authorized users are denied access.

The relationship between FRR (Type I) and FAR (Type II) is depicted in the graphic below

As one rate increases, the other decreases.

The Cross-over Error Rate (CER) is sometimes considered a good indicator of the overall accuracy of a biometric system.

This is the point at which the FRR and the FAR have the same value.

Solutions with a lower CER are typically more accurate.

See graphic below from Biometria showing this relationship.The Cross-over Error Rate (CER) is also called the Equal Error Rate (EER), the two are synonymous.

Cross Over Error Rate - The other answers are incorrect: Type I error is also called as False Rejection Rate where a valid user is rejected by the system.

Type III error : there is no such error type in biometric system.

Crossover error rate stated in percentage , represents the point at which false rejection equals the false acceptance rate.

Reference(s) used for this question: http://www.biometria.sk/en/principles-of-biometrics.html and Shon Harris, CISSP All In One (AIO), 6th Edition , Chapter 3, Access Control, Page 188-189 and Tech Republic, Reduce Multi_Factor Authentication Cost.

When a biometric system is used, it may sometimes grant access to impostors who should be rejected, or reject access to authorized users who should be granted. These are known as error types, and there are two main types of errors in biometric systems: Type I errors and Type II errors.

Type I errors occur when the system incorrectly grants access to someone who should be rejected. This is also known as a false positive. In other words, the system mistakenly identifies an impostor as an authorized user and allows them access.

Type II errors, on the other hand, occur when the system incorrectly rejects access to someone who should be granted. This is also known as a false negative. In other words, the system mistakenly identifies an authorized user as an impostor and denies them access.

Type III errors and crossover errors are not typically used to describe errors in biometric systems. Type III errors are more commonly used in statistical hypothesis testing, where they refer to errors caused by incorrect conclusions drawn from data. Crossover error refers to a type of error that occurs when two different biometric systems have different error rates and the point at which their error rates cross over changes over time.

In summary, the error type that deals with the possibility of granting access to impostors who should be rejected is Type I error.