Which of the following is NOT part of the Kerberos authentication protocol? 

Answer options:

A. Symmetric key cryptography
B. Authentication service (AS)
C. Principals
D. Public Key

D

There is no such component within kerberos environment.Kerberos uses only symmetric encryption and does not make use of any public key component. The other answers are incorrect because : Symmetric key cryptography is a part of Kerberos as the KDC holds all the users` and services` secret keys. Authentication service (AS) : KDC (Key Distribution Center) provides an authentication service Principals : Key Distribution Center provides services to principals , which can be users , applications or network services. References: Shon Harris , AIO v3 , Chapter - 4: Access Control , Pages : 152-155.