ITPEC FE Morning October 2022 Question 42
ITPEC FE Morning October 2022 — Question 42 of 80
Biometric Authentication — FRR vs FAR tradeoff — adjusting the sensitivity threshold of a biometric system.
Biometric systems have two key error rates:
- •FRR (False Rejection Rate) — probability of rejecting an authorized user
- •FAR (False Acceptance Rate) — probability of accepting an unauthorized user
When introducing biometric authentication, the device must be adjusted by considering both FRR and FAR, because tightening the threshold reduces FAR but increases FRR, and vice versa.
Why not others:
- (b) Malware definition updates — relates to antivirus software, not biometric systems
- (c) Digital certificate from a third party — relates to PKI authentication, not biometrics
- (d) Knowledge-based authentication balance — describes password/PIN design (something you know), not biometrics (something you are)
Key rule: Biometric tuning is always a tradeoff between FRR and FAR — adjusting the threshold affects both rates inversely.
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