Digital signatures mainly go through the following processes: the information sender uses a one-way hash function (HASH function) to generate a message summary; the message sender uses his own private key to sign the message summary; the message is sent The sender sends the message itself and the signed message digest together; the message receiver generates a new message digest for the received message itself by using the same one-way hash function (HASH function) used by the message sender, and then uses the message The sender's public key verifies the message digest to confirm the identity of the message sender and whether the message has been modified. Digital encryption mainly goes through the following processes: When the information sender needs to send information, he first generates a symmetric key and uses the symmetric key to encrypt the message to be sent; the information sender uses the public key of the information receiver to encrypt the above symmetric key. Key; the information sender combines the results of the first and second steps and sends them to the information receiver, which is called a digital envelope; the information receiver uses his own private key to decrypt the encrypted symmetric key, and then uses this symmetric The key decrypts the ciphertext encrypted by the sender and obtains the real original text. Although the processes of digital signature and digital encryption both use public key systems, the implementation processes are exactly the opposite, and the key pairs used are also different. The digital signature uses the sender's key pair. The sender uses his own private key to encrypt, and the receiver uses the sender's public key to decrypt. This is a one-to-many relationship. Anyone who has the sender's public key Anyone with the key can verify the correctness of the digital signature. Digital encryption uses the recipient's key pair, which is a many-to-one relationship. Anyone who knows the recipient's public key can send encrypted information to the recipient. Only the only person who has the recipient's private key can Decrypt the information. In addition, digital signatures only use asymmetric key encryption algorithms, which can ensure the integrity, identity authentication and non-repudiation of sent information, while digital encryption uses a combination of symmetric key encryption algorithms and asymmetric key encryption algorithms. method, which can ensure the confidentiality of sent information.