Which of the following is a principal PKI component?

• A. Public Key Certificates
• B. Certificate Revocation Lists
• C. Certificate Authority
• D. Public/Private Key Pairs

Answer: (C)

In PKI, trust is anchored in the entity that validates identities and signs certificates. The Certificate Authority serves as this trusted anchor: it verifies who you are or what you claim to be, then signs a certificate that binds your identity to your public key. Once your certificate is signed by the CA, others can verify it using the CA’s public key, establishing a chain of trust. The CA’s role is fundamental because, without a trusted CA signing and issuing certificates, no one can reliably confirm that a given certificate belongs to the stated entity.

Public Key Certificates are the actual certificates that contain the identity, the public key, and metadata; they rely on the CA to be trusted, but they aren’t the trust anchor themselves. Certificate Revocation Lists are used to indicate certificates that should no longer be trusted, which supports maintaining trust but doesn’t establish it. Public/Private Key Pairs are the cryptographic material used for encryption and signing, but they don’t by themselves establish identity or trust; they’re the tools that the CA signs into certificates.