What is public key and private key?

Public key and private key are a key pair obtained through an encryption algorithm (a public key and a private key, that is, asymmetric encryption). The public key can encrypt the session and verify the digital signature, and only the corresponding private key can decrypt the session data, thus ensuring the security of data transmission. The public key is the public part of the key, and the private key is the non-public part that is kept by the user. The key pair obtained by the encryption algorithm can be guaranteed to be unique in the world. When using a key pair, if you encrypt a piece of data with one of the keys, you can only decrypt the data using the other key in the key pair. For example, data encrypted with a public key must be decrypted with the corresponding private key; if encrypted with a private key, it must also be decrypted with the corresponding public key, otherwise the decryption will fail.