It is the process of verifying a user´s identity.
Authentication is the verification of identity of a service user. The following basic methods for identifying identity are being used:
- depending on what the user knows (he knows the correct combination of user ID and password or PIN),
- depending on what the user has (some technical device that user owns – hardware key, smart card, private key, etc.),
- depending on what the user is (the user has biometric properties that can be checked – fingerprint, iris or retina image, etc.),
- depending on what the user can do (he can correctly answer a randomly generated control question).
For example
- enter the user name and the corresponding password,
- possession of a personal certificate and knowledge of its private key, etc.,
- putting an identification chip card,
- authentication using a previously stored fingerprint,
- scanning the iris,
- etc.
Today, a multi-factor authentication is often used, when more methods of authentication are combined.