"Digital signature" is an electronic password composed of a series of symbols and codes generated by some cryptographic operation, rather than a handwritten signature or seal. This kind of electronic signature can also be technically verified, and its verification accuracy is incomparable to that of general manual signature and stamp verification. "Digital signature" is a kind of electronic signature method with the most common application, the most mature technology and the strongest operability in e-commerce and e-government. It uses standardized procedures and scientific methods to identify signers and approve electronic data content. It can also verify whether the original text of the file has changed during transmission, and ensure the integrity, authenticity and non-repudiation of the transmitted electronic file. Thanks to the technology of Internet e-commerce system, customers who shop online can get the information of businesses and enterprises very conveniently and easily, but at the same time, it also increases the risk of abusing some sensitive or valuable data.

In order to ensure the security and confidentiality of online electronic transactions and payments, and prevent fraud in the process of transactions and payments, it is necessary to establish a trust mechanism on the Internet. This requires that both buyers and sellers involved in e-commerce must have legal identities and can be effectively and correctly verified online.

Digital certificate is an authoritative electronic document. It provides a way to verify your identity on the Internet, similar to the driver's license or ID card in daily life. It is authorized by the authority-CA Certificate.

Authority) center, which people can use to identify each other in Internet communication. Of course, CA, as an authoritative, fair and reliable third party, plays an important role in the process of digital certificate authentication.