Fingerprint scanner

A fingerprint scanner is a device that reads the papillary pattern of a finger and uses it for biometric identification. It is used in ACS terminals, authentication systems and bank workstations.

What is a fingerprint scanner

A fingerprint scanner (fingerprint reader) is a biometric device that registers the unique pattern of lines on a fingertip. The read pattern is converted into a digital template, which is compared with the template saved during user registration. The fingerprint is unique for each person and practically cannot be forged, so biometrics is considered a reliable method of identity confirmation. Scanners are built into ACS terminals, laptops, smartphones and standalone workstations, and are also used in banks for access to operating systems and protected operations.

Types of fingerprint scanners

By reading technology there are optical, capacitive, ultrasonic and thermal scanners. Optical scanners photograph the finger and are cheap to produce, capacitive ones measure the charge difference on papillary ridges and are more protected from forgery, ultrasonic ones penetrate under the skin and work even with wet fingers. Thermal scanners record the temperature difference between the ridges and valleys of the pattern. For ACS and banks, scanners with high recognition accuracy, a response speed of less than a second and protection against spoofing attempts are chosen.

How biometric identification works

The process consists of registration and verification. During registration, the fingerprint is read several times, characteristic points (minutiae) are extracted from it and a template is created, which is stored in a protected repository — the local database of the terminal or the ACS server. During verification, the presented finger is scanned again, the template is compared with the saved one and, if there is a match, access is allowed. Unlike passwords, biometrics cannot be forgotten, but templates must be stored in accordance with personal data requirements: usually it is not the image itself that is stored, but the mathematical template of the pattern.

Advantages and limitations

The advantages are high speed (fractions of a second), the impossibility of remembering or transferring biometrics, and combination with cards and PIN for two-factor authentication. The limitations are recognition failure with damaged skin or wet hands, the need to control devices against forgery and the processing of biometric data strictly by law with the consent of the owner. The false rejection rate (FRR) and false acceptance rate (FAR) differ between models, and for banking systems, models with a low FAR are important. Scanners are combined with passport readers when accepting clients and with working time tracking terminals.

Where fingerprint scanners are used

Fingerprint scanners are used at checkpoints and vaults, where strict access control is needed, in working time tracking systems, and at bank workstations to log into the system and confirm operations. They work as part of an ACS: an employee presents a fingerprint instead of a card or together with it. To protect operations, a bank may require biometric confirmation of sensitive actions, and client biometrics are used in remote service with consent. The choice of a specific scanner depends on the required accuracy, installation conditions and integration with the security system.