Biometric
Definition
Any measurable physiological or behavioural trait used to identify or verify an individual. Falls in the 'something you are' authentication category, distinct from 'something you know' (password) and 'something you have' (token, smart card).
- Category
- "Something you are" authentication factor
- Contrast factors
- Something you know (password), something you have (token)
- Types
- Physiological (fingerprint, iris) or behavioural (gait, voice)
- Field
- Biometric identification systems
Common questions
Why is a biometric trait treated differently from a password for security purposes?+
A password can be changed if compromised, but a biometric trait generally cannot be reissued, so a leaked biometric template carries a permanent exposure risk. This is why biometric systems typically store irreversible templates rather than raw trait images.
Can a physiological and a behavioural biometric be combined in one system?+
Yes, this is called multimodal biometrics. Combining, for example, fingerprint with voice or gait reduces the false acceptance and false rejection rates that any single modality carries on its own, at the cost of added capture complexity.
Related terms
- Behavioural Biometric
- Trait rooted in learned action: voice, gait, signature dynamics, keystroke dynamics, mouse movement.
- Enrolment
- First-time capture of a biometric, feature extraction, and storage of the resulting template in the system database.
- FAR / FRR / EER
- False Acceptance Rate (imposter wrongly accepted), False Rejection Rate (genuine user wrongly rejected), and Equal Error Rate (operating point where FAR =...
- Identification (1:N)
- Searching a fresh sample against EVERY template in the database to find a match. Used by AFIS to hit a chance print...
- Physiological Biometric
- Trait rooted in body structure: fingerprint, iris, retina, face, palm print, palm vein, hand geometry, ear shape, DNA.
- Presentation Attack Detection (PAD)
- Liveness checks that block spoofing with fake fingers, photos, iris printouts or cloned voice. Evaluated under ISO/IEC 30107.
- Verification (1:1)
- Matching a fresh sample against ONE stored template tied to a claimed identity. Used to unlock a phone or authenticate a payment.