In biometric systems, a false rejection occurs when a legitimate user is denied access.

• A. True
• B. False
• C. Not sure
• D. Both

Answer: (A)

In biometric authentication, false rejection refers to denying access to someone who is actually legitimate. This happens when the system fails to recognize a real user as a match, often due to noisy input, poor sample quality, or a threshold that’s set too strictly. The result is that an authorized user is blocked from logging in, which is exactly what a false rejection describes. The opposite situation would be a false acceptance, where an impostor is granted access. The threshold that determines a match score versus acceptance creates a trade-off: making the system more permissive reduces false rejections but increases false acceptances, while making it stricter increases false rejections and reduces false acceptances. So the statement is true.