Which entity issues digital certificates?

• A. Certificate Authority (CA)
• B. Registration Authority (RA)
• C. Certificate Revocation List (CRL)
• D. Hierarchical Trust Model

Answer: (A)

In public key infrastructure, the certificate that binds a public key to an identity is issued by the certificate authority, the trusted party that signs certificates to attest legitimacy. The CA uses its private key to create a digital signature on the certificate, which others can verify using the CA’s public key, establishing trust in the binding between the identity and the key. The registration authority helps by handling enrollment and identity verification on behalf of the CA, but it does not issue certificates on its own. A certificate revocation list is a list published by the CA of certificates that are no longer trusted, not a issuing entity. A hierarchical trust model describes how trust is arranged across potential multiple CAs (root and intermediate) rather than a single issuer. So, the entity that issues digital certificates is the certificate authority.