CA authentication, that is, electronic authentication service, refers to the activities of providing authenticity and reliability verification for all parties involved in electronic signature.

A certificate authority (CA) is an organization that issues digital certificates. It is the authority responsible for issuing and managing digital certificates. As a trusted third party in e-commerce transactions, it is responsible for verifying the legitimacy of public keys in public key systems. CA is the issuing authority of certificate and the core of PKI. CA is the authority responsible for issuing certificates, authenticating certificates and managing issued certificates. It is necessary to formulate policies and specific steps to verify and identify the user's identity and sign the user's certificate to ensure the identity of the certificate holder and the ownership of the public key.