An authentication protocol is a type of computer communications protocol or cryptographic protocol specifically designed for transfer of authentication data between two entities.

In information security, message authentication or data origin authentication is a property that a message has not been modified while in transit (data integrity) and that the receiving party can verify the source of the message.

An authentication server provides a network service that applications use to authenticate the credentials, usually account names and passwords, of their users.

Security protocol for data integrity.

a notion with several definitions.

Verification using unique biological characteristics.