Which
of the following uses a Key Distribution Center (KDC) to authenticate a principle?
A.
CHAP
B.
PAP
C.
Kerberos
D.
TACACS
Explanation:
Kerberos uses a Key Distribution Center (KDC) to authenticate a principle.
Kerberos is a computer network authentication protocol that allows individuals communicating over
a non-secure network to prove their
identity to one another in a secure manner. Kerberos builds on symmetric key cryptography and
requires a trusted third party. Kerberos uses
as its basis the Needham-Schroeder protocol. It makes use of a trusted third party, termed a key
distribution center (KDC), which consists of
two logically separate parts:
Authentication Server (AS)
Ticket Granting Server (TGS)Kerberos works on the basis of tickets, which serve to prove the identity of users. The KDC maintains
a database of secret keys; each entity
on the network, whether a client or a server, shares a secret key known only to itself and to the KDC.
Knowledge of this key serves to prove
an entity’s identity. For communication between two entities, the KDC generates a session key,
which they can use to secure their
interactions.
Answer option D is incorrect. Terminal Access Controller Access-Control System (TACACS) is a
remote authentication protocol that is used to
communicate with an authentication server commonly used in UNIX networks. TACACS allows a
remote access server to communicate with an
authentication server in order to determine if the user has access to the network. TACACS allows a
client to accept a username and password
and send a query to a TACACS authentication server, sometimes called a TACACS daemon. It uses
UDP port 49 as the default port.
Answer option A is incorrect. Challenge Handshake Authentication Protocol (CHAP) is an
authentication protocol that uses a secure form of
encrypted authentication. Using CHAP, network dial-up connections are able to securely connect to
almost all PPP servers.
Answer option B is incorrect. Password Authentication Protocol (PAP) is the least sophisticated
authentication protocol, used mostly when a
client calls a server running an operating system other than Windows. PAP uses plain text
passwords.