Digital certificate adopts public key system (such as RSA). Each user sets a private key that only he knows, and uses it to decrypt and sign; At the same time, a public key is set and shared by a group of users for encryption and signature verification.

Using digital certificates, you can confirm the following two points:

(1) The guarantee information was sent by the signer himself, and the signer cannot and cannot deny it.

(2) Ensure that the information has not been modified from publication to receipt, and that the published information is true.