Unlock your smartphone or laptop with the touch of a finger has become normal during the last couple of years. This is made possible by the development of various fingerprint readers. So how do they work?

A fingerprint in its narrow sense is an impression left by the friction ridges of a human finger. Fingerprints are easily deposited on suitable surfaces (such as glass or metal or polished stone) by the natural secretions of sweat from the eccrine glands that are present in epidermal ridges. Human fingerprints are detailed, nearly unique, difficult to alter, and do not change over the life of an individual, making them suitable as long-term markers of human identity.

Fingerprint recognition or fingerprint authentication refers to the automated method of verifying a match between two human fingerprints. Fingerprints are one of many forms of biometrics used to identify individuals and verify their identity.