According to "Electronic Signature Law", when electronic signature data is used for electronic signature, it belongs to the electronic signer. When signing, the electronic signature production data is only controlled by the electronic signer.

The electronic signature is signed with the private key of the digital certificate, so the digital certificate should be exclusively controlled by the electronic signer, which is in line with the electronic signature law. Moreover, you said that many people have to issue different certificates to the parties to the contract with one certificate, which is obviously illegal.

Article 1 This Law is formulated in order to standardize electronic signatures, establish the legal effect of electronic signatures and safeguard the legitimate rights and interests of the parties concerned.

Article 2 The term "electronic signature" as mentioned in this Law refers to the data contained in a data message to identify the identity of the signer and show that the signer approves its contents.

The term "data message" as mentioned in this Law refers to information generated, sent, received or stored by electronic, optical, magnetic or similar means.

Article 3 In civil activities, the parties may agree on the use or non-use of electronic signatures and data messages in contracts or other documents and documents.

A document in the form of electronic signature or data message agreed by the parties shall not be denied its legal effect just because it is in the form of electronic signature or data message.