Digital certificate verification is carried out by security authentication application software, so the verifier must verify the certificate chain, that is, from the bottom of the trust domain of the other CA, query up layer by layer, trace back to the end of the trust chain, usually the root CA, and find the signature of the authoritative root CA, that is, complete the verification.

Verification needs to include the following contents: certificate integrity verification, that is, to confirm that this certificate has not been tampered with by others. This verification can be done by verifying the digital signature of the CA in the certificate. Certificate credibility verification is to confirm that the certificate is issued by a trusted CA.

A digital certificate is a series of numbers that represent the identity information of all communication parties in Internet communication. It provides a method to verify the identity of communication entities on the Internet. A digital certificate is not a digital ID card, but a seal or seal stamped by an identity authentication institution or a signature added to a digital ID card. It is issued by CA, also known as Certificate Authority Center. People can identify each other with digital certificates online.