Biometrics is the unambiguous recognition of people based on their physical attributes (fingerprints, retinas, iris, face, etc.) or behaviour (signature, stride, or even typing), distinct and unmistakable. They do not change over time and are unaffected by external factors.

This method is comparable to the one that humans use to recognise and identify their peers based on their physical appearance, voice, or walking style.

Depending on the recognition system utilised, we may refer to voice biometrics, facial and eye recognition, among other things.