According to the Electronic Signature Law of People's Republic of China (PRC), a reliable electronic signature has the same legal effect as a handwritten signature or seal. An electronic contract with legal effect has the following four elements: true identity (when electronic signature data is used for electronic signature, it belongs exclusively to the electronic signer). True will (when signing, the electronic signature production data is only controlled by the electronic signer). The signature has not been changed (any changes to the electronic signature after the signature can be found). The original text has not been changed (any changes in the content and form of the data message can be found after signing).