Many computers have a fingerprint scanner. This allows for some security.

Biometrics is a field of study which identifies or recognises people by the traits they have. Not to be confused with biometry, the application of statistics to biology.

Given those traits, a system can be trained to recognise certain people, with a certain probability. Training lowers the probability of falsely identifying someone.

The traits used are of two types:

• Based on the body (physiological traits). These include fingerprints, face recognition, scent, voice recognition, iris (eye), or retina recognition.
• Based on the behaviour of a person.