Which statement best describes the role of a Certificate Authority regarding public keys?

Which statement best describes the role of a Certificate Authority regarding public keys?

• A. It encrypts all traffic between client and server
• B. It registers the domain name
• C. It verifies that the public key actually belongs to the claimed website
• D. It assigns IP addresses to websites

Answer: (C)

A Certificate Authority exists to prove that a public key truly belongs to the website it's paired with. It checks that the requester controls the domain (and sometimes validates organizational identity) and then signs a certificate that binds that domain to a specific public key. When your browser connects, it trusts certificates from trusted CAs and validates that the certificate is legitimate and issued for the site you’re visiting. If the certificate checks out, the site proves it owns the corresponding private key, and a secure TLS connection can be established with the correct keys. The other ideas aren’t accurate descriptions of what a CA does: it doesn’t encrypt all traffic itself—encryption is negotiated during the TLS handshake using session keys; it isn’t responsible for registering domain names; and it doesn’t assign IP addresses to websites.

A Certificate Authority exists to prove that a public key truly belongs to the website it's paired with. It checks that the requester controls the domain (and sometimes validates organizational identity) and then signs a certificate that binds that domain to a specific public key. When your browser connects, it trusts certificates from trusted CAs and validates that the certificate is legitimate and issued for the site you’re visiting. If the certificate checks out, the site proves it owns the corresponding private key, and a secure TLS connection can be established with the correct keys.

The other ideas aren’t accurate descriptions of what a CA does: it doesn’t encrypt all traffic itself—encryption is negotiated during the TLS handshake using session keys; it isn’t responsible for registering domain names; and it doesn’t assign IP addresses to websites.