Explanation/Reference:
Explanation:
Internet Key Exchange (IKE) is not included in a Public Key Infrastructure (PKI). IKE is a key management protocol used in IPSec.
A PKI may be made up of the following entities and functions:
Certification authority

Registration authority

Certificate repository

Certificate revocation system

Key backup and recovery system

Automatic key update

Management of key histories

Timestamping

Client-side software

Incorrect Answers:
A: Timestamping is included in a Public Key Infrastructure (PKI).
B: Repository (certificate repository) is included in a Public Key Infrastructure (PKI).
C: Certificate revocation is included in a Public Key Infrastructure (PKI).
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, p. 839