Signature key and encryption key. Because public keys have two different uses, they need to be configured with digital signature/verification respectively in practical applications. The key pair and key pair used for data encryption/decryption, here called signature key pair and encryption key pair respectively, have different requirements for key management due to their different uses. A signature key pair consists of a signature private key and a verification public key. The signature private key is the proof of the sender's identity and has the effect of official seal in daily life. In order to ensure its uniqueness, the signature private key can never be backed up and archived, and only a new key pair needs to be generated after it is lost.