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. Generally speaking, the identification of electronic signatures is from a technical point of view. It mainly refers to the security measures to identify the identities of both parties to the transaction and ensure that the transaction data content is not tampered with through specific technical solutions. In a broad sense, electronic signature includes not only our usual "asymmetric key encryption", but also computer passwords, biometric handwriting recognition, fingerprint recognition, and emerging eye-iris perspective recognition and facial pattern recognition. As the most mature "digital signature" at present, electronic signature technology is made of "asymmetric" cryptographic technology of public key and key.