Which elements are commonly considered core components of a Public Key Infrastructure (PKI)?

• A. Issuing policy, encryption algorithm, network firewall, vulnerability scanner
• B. Certificate Authority, Registration Authority, Certificates, Distribution
• C. Client software, server software, database, load balancer
• D. Public key, private key, hash function, digital signature

Answer: (B)

PKI is about trusted management of digital certificates and the relationships among the entities that issue, verify, and distribute them. The essential pieces are the Certificate Authority, which signs and issues certificates binding a public key to an identity; the Registration Authority, which verifies identities and handles certificate requests on behalf of the CA; the certificates themselves, which are the digital documents containing the identity, public key, and metadata, signed by the CA; and the distribution mechanism, including how certificates and revocation information are published so relying parties can access and trust them. Together, these elements create the trust chain and lifecycle management that PKI provides.

The other options mix in items that are not PKI’s core components. An issuing policy and encryption algorithm relate to governance and cryptographic choices rather than the PKI’s structural parts, and firewall or vulnerability scanning tools are general security infrastructure rather than PKI components. A basic IT stack like client software, server software, databases, and load balancers describes deployment anatomy rather than PKI’s trust-centric framework. Lastly, public and private keys, hash functions, and digital signatures are cryptographic primitives used within PKI, but they aren’t the organizational components that define the PKI architecture itself.