Not only in modern times, but even from ancient times, humans have used physical characteristics to be recognized for several centuries. Bertillon, an official of the police department of Paris in the nineteenth century was a pioneer in identifying criminals based on some physical characteristics. However, the boom of this technology was already occurring in the XXI century, in which many automated recognition methods appear from biometric measures, which include:
The face features (facial recognition)
Fingerprints (Biometrics fingerprint)
The veins of the fingers (Biometrics veins)
Other biometrics such as eye iris or voice.