In PKI, which entity is responsible for signing certificates and establishing trust?

In PKI, which entity is responsible for signing certificates and establishing trust?

• A. Certificate Authority
• B. DNS
• C. Firewall
• D. VPN

Answer: (A)

Public Key Infrastructure relies on a trusted Certificate Authority to bind identities to public keys by signing digital certificates. The CA verifies who you are or what you claim to be, then uses its private key to sign the certificate. Anyone who trusts that CA can verify the certificate’s signature with the CA’s public key (which lives in the client’s trust store). This creates a chain of trust: the certificate asserts the public key belongs to a specific entity, and the CA’s signature confirms that assertion. Without the CA’s signing, there’s no trusted way to confirm who a certificate belongs to. DNS, on the other hand, maps names to IP addresses and has no role in issuing or signing certificates. A firewall is a network security device that controls traffic, not a certificate authority. A VPN creates a secure tunnel for traffic but doesn’t issue certificates or establish trust by itself.

Public Key Infrastructure relies on a trusted Certificate Authority to bind identities to public keys by signing digital certificates. The CA verifies who you are or what you claim to be, then uses its private key to sign the certificate. Anyone who trusts that CA can verify the certificate’s signature with the CA’s public key (which lives in the client’s trust store). This creates a chain of trust: the certificate asserts the public key belongs to a specific entity, and the CA’s signature confirms that assertion. Without the CA’s signing, there’s no trusted way to confirm who a certificate belongs to.

DNS, on the other hand, maps names to IP addresses and has no role in issuing or signing certificates. A firewall is a network security device that controls traffic, not a certificate authority. A VPN creates a secure tunnel for traffic but doesn’t issue certificates or establish trust by itself.