Authentication protocol

[1] It is the most important layer of protection needed for secure communication within computer networks.

Stealing someone's identity is easy in the computing world - special verification methods had to be invented to find out whether the person/computer requesting data is really who he says he is.

The authentication process in this protocol is always initiated by the server/host and can be performed anytime during the session, even repeatedly.

The client uses the password and the string received as input to a hash function and then sends the result together with username in plain text.

More than 40 EAP-methods exist, the most common are: Complex protocols used in larger networks for verifying the user (Authentication), controlling access to server data (Authorization) and monitoring network resources and information needed for billing of services (Accounting).

The oldest AAA protocol using IP based authentication without any encryption (usernames and passwords were transported as plain text).

Remote Authentication Dial-In User Service (RADIUS) is a full AAA protocol commonly used by ISPs.

Credentials are mostly username-password combination based, and it uses NAS and UDP protocol for transport.