An electronic signature is a form of electronic signature using a digital certificate. The premise of an electronic signature is to have a digital certificate.
A digital certificate is an electronic document issued by a trusted third-party authority (called a certificate authority or CA) to verify the authenticity and integrity of a digital signature. A digital certificate contains the signer's public key and other identity information, and is digitally signed by a certificate authority to ensure the credibility of the certificate.
When performing an electronic signature, the signer uses his own private key to digitally sign the file, and then attaches the public key in the digital certificate to the file along with the signature. The recipient can use the public key in the signer's digital certificate to verify the authenticity and integrity of the signature to determine whether the file has been tampered with.
The role of the digital certificate is to ensure the identity of the signer and the credibility of the signature, so before the electronic signature, the signer needs to obtain a valid digital certificate. This usually requires applying to a certificate authority, and going through identity verification and other procedures to ensure the legitimacy of the certificate.