What is the role of a Certificate Authority in public key infrastructure?

• A. To issue and verify digital certificates
• B. To encrypt user data
• C. To perform encryption and decryption
• D. To manage user passwords

Answer: (A)

The role of a Certificate Authority (CA) in public key infrastructure (PKI) is primarily to issue and verify digital certificates. A digital certificate is a credential that binds a public key to the identity of an individual, organization, or device. It serves as a means for users to trust that the public key contained within the certificate belongs to the entity it claims to represent.

When a CA issues a digital certificate, it performs a thorough verification process to ensure that the requesting party is legitimate. This enhances the trustworthiness of the entity's public key because it has been validated by a trusted third party—the CA. The CA also maintains a revocation list that informs users when certificates are no longer valid, providing ongoing verification of the authenticity of the certificates it has issued.

This function is critical in ensuring secure communications, as users rely on the digital certificates to establish secure connections, verify identities, and facilitate secure transactions over the internet. Hence, the correct answer emphasizes the CA's essential responsibility within the PKI ecosystem.