See GitHub authentication code, MFA
Authentication (from Greek: αὐθεντικός authentikos, "real, genuine", from αὐθέντης authentes, "author") is the act of proving an assertion, such as the identity of a computer system user. In contrast with identification, the act of indicating a person or thing's identity, authentication is the process of verifying that identity.
Authentication is relevant to multiple fields. In art, antiques, and anthropology, a common problem is verifying that a given artifact was produced by a certain person, or in a certain place (i.e. to assert that it is not counterfeit), or in a given period of history (e.g. by determining the age via carbon dating). In computer science, verifying a user's identity is often required to allow access to confidential data or systems. It might involve validating personal identity documents.