If there is information stored in the system for the signer, it can be directly filtered and viewed in the system. Simply put, electronic signature is the technology of directly signing and stamping electronic documents by using hash algorithm and encryption algorithm. In order to ensure the legal effect of the signed electronic document, the electronic document signed by electronic signature also needs to have the characteristics of recognizable signature identity and tamper-proof signature content.

In order to meet the requirements of confidentiality of electronic contract content and sender authentication, asymmetric encryption is adopted for electronic signature. When sending a contract, the sender of the contract encrypts the proposed electronic contract with his own private key and sends it. When receiving the contract, if the sender's public key can be used to decrypt it, it means that the document was sent by the sender himself.

After receiving the contract, how can the contract receiver confirm that it is the sender's public key?

Electronic signature with the help of CA (full name certificate authority) applies for the sender's public key and uses it to decrypt the electronic contract. Successful decryption means that the sender is himself. Confirm the identity of the document sender.