Which of the following elements is not included in a Public Key Infrastructure (PKI)?

A.
Timestamping

B.
Lightweight Directory Access Protocol (LDAP)

C.
Certificate revocation

D.
Internet Key Exchange (IKE)

Explanation:
Public key cryptography is one mechanism that is often used to fulfill the security requirements
necessary to conduct electronic transactions over public networks. PKI (public key infrastructure)
and cryptography based solutions are taking the lead in secure ecommerce. PKI addresses
nonrepudiation of identity using a dual-key encryption system that allows users to uniquely sign
documents with a digital signature. Public key cryptography uses pairs of keys, each pair consisting
of one public key and one private key. Information encrypted with one key in the pair can only be
decrypted with the other key. LDAP is issued to bring user information and Timestamping to track
changes over time. PKI also relies on certificated and CRL (Certificate Revocation list) to discard
compromised, expired digital certificates.