According to the provisions of the Electronic Signature Law, let's take us as an example to talk about the conditions that an electronic signature needs to meet: In China, the Ministry of Industry and Information Technology has promulgated the Administrative Measures for Electronic Authentication Services, which stipulates that "if an electronic signature needs third-party authentication, it shall be provided by a legally established electronic authentication service provider".

According to the United Nations Model Law on Electronic Commerce, an electronic signature is data in electronic form contained in, attached to or logically associated with a data message, which can be used to verify the identity of the signatory related to the data message.

And indicate that the signatory approves the information contained in the data message; The European Union's Electronic Signature Directive stipulates that "electronic signature" generally refers to "data in electronic form connected or logically connected with other electronic records and used as authentication methods."

The sender encrypts the file with the public key of the receiver issued by CA, and signs the file with its own key. When the recipient receives the file, he first analyzes the signature with the sender's public key to prove that the file is indeed sent by the sender. Then use your own private key to decrypt the file and read it.

Electronic signature is the general name of modern authentication technology. According to the Uniform Electronic Transactions Act of the United States, "electronic signature" refers to "an electronic sound, symbol or program associated with or logically associated with an electronic record, which is signed or adopted by someone for signing an electronic record".