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 and private 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 regenerated after it is lost. You need to archive the verification public key to verify the old digital signature.

A key is a parameter entered in an algorithm for converting plaintext into ciphertext or ciphertext into plaintext. Keys are divided into symmetric keys and asymmetric keys. Reading functional cryptography: secretkey)-secret key; Privatekey)-private key; Publickey)-public key.