Why do certificate Authorities (CA) add value to the security of electronic commerce transactions?

CAs maintain the Certificate Revocation List (CRL), which is a published list of digital certificates that have been revoked before their expiration date due to compromise, mis-issuance, or other reasons. This list is critical to e-commerce security because it allows browsers, servers, and other relying parties to check whether a certificate presented during a transaction is still valid and trustworthy, preventing the use of compromised credentials.

CAs never maintain or store the private keys of transaction parties; private keys are generated by the entity themselves and must remain secret and under the sole control of the key owner to preserve the integrity of asymmetric cryptography.

CAs verify the identity of certificate applicants and sign their public keys, not their private keys; verifying a private key would be a security violation since private keys must never be disclosed to any third party.

CAs do not provide a secure communication channel to transaction parties; secure channels are established through protocols such as TLS/SSL, which use the certificates issued by CAs but are separate from the CA's own functions.