What is the primary role of a Certificate Authority (CA) in digital security?

The primary role of a Certificate Authority (CA) in digital security is to act as a trusted third party that issues and signs digital certificates. A digital certificate serves as a proof of identity for individuals, organizations, or devices, allowing them to establish secure communications and transactions over the internet. When a CA signs a certificate, it validates the identity of the entity requesting the certificate, ensuring that users can trust that they are communicating with the legitimate owner of the certificate.

This process is crucial for public key infrastructure (PKI), where the CA's signature adds a layer of trust. By ensuring that only verified entities receive digital certificates, the CA helps prevent impersonation and ensures that the encryption keys associated with each certificate can be trusted. Consequently, this trust is foundational for secure web browsing, email, and other online services.

The other choices do not correctly define the central function of a CA. While some may touch on aspects of digital security, they do not encapsulate the essential role of a CA in signing and verifying identities within digital communications.