{{Short description|Type of cryptographic protocol}}
An '''authentication protocol''' is a type of computer [[communications protocol]] or [[cryptographic protocol]] specifically designed for transfer of [[authentication]] data between two entities. It allows the receiving entity٠entity to authenticate the connecting entity (e.g. Client connecting to a Server) as well as authenticate itself to the connecting entity (Server to a client) by declaring the type of information needed for authentication as well as syntax.<ref>{{cite web|url = https://www.sans.org/reading-room/whitepapers/authentication/overview-authentication-methods-protocols-118|title = An Overview of Different Authentication Methods and Protocols|date = 23 October 2001|access-date = 31 October 2015|website = www.sans.org|publisher = SANS Institute|last = Duncan|first = Richard}}</ref> It is the most important layer of protection needed for secure communication within computer networks.
