Within Kerberos, which part is the single point of failure?

Within Kerberos, which part is the single point of failure?

A.
The Ticket Granting Ticket

B.
The Realm

C.
The Key Distribution Center

D.
The Client-Server session key

Explanation:
C is the correct answer because the KDC is the only service within Kerberos that can authenticate subjects. If the KDC losses availability, then ticket granting tickets will not be issued and no new authentications may take place.

Incorrect Answers and Explanations: A, B, and D: A is incorrect because the TGT is received by the subject from the KDC. B is incorrect because the realm is a Kerberos network that shares authentication. D is incorrect because new C-S session keys can be issued.