Electronic signature, like the digital certificate we use, is a means of identity verification, which generally refers to all electronic forms attached to electronic documents and logically associated with them. It can be used to identify the identity of the signer of electronic documents, ensure the integrity of documents, and show that the signer agrees with the factual contents stated in electronic documents. Electronic signature, a form of expression of electronic signature Generally speaking, electronic signature includes two different forms of expression: signature and seal, and seal is a form of expression of electronic signature.