The principle of symmetric encryption is that the data sender turns plaintext (original data) and encryption key into complex encrypted ciphertext after processing by special encryption algorithm. After receiving the ciphertext, if the receiver wants to interpret the original text, it needs to use the encryption key and the inverse algorithm of the same algorithm to decrypt the ciphertext, so as to restore it to readable plaintext.

The principle of asymmetric encryption is that Mr. Party A forms a pair of keys and uses one of them as the public key. Party B who has obtained the public key encrypts the information to be encrypted with the key and sends it to Party A; Party A uses another corresponding private key to decrypt the encrypted information, thus realizing the transmission of confidential data.

The differences between symmetric encryption and asymmetric encryption are: different keys, different security and different digital signatures.

First, the keys are different.

1, symmetric encryption: symmetric encryption and decryption use the same key.

2. Asymmetric encryption: Asymmetric encryption and decryption do not use the same key, and encryption and decryption need two keys.

Second, the security is different.

1. symmetric encryption: If you use symmetric encryption to transmit encrypted files through the network, you may be eavesdropped no matter how you tell the other party the key.

2. Asymmetric encryption: Because asymmetric encryption contains two keys, and only the "public key" can be made public, the receiver only needs to decrypt it with his own private key, which can well avoid the security problems in the process of key transmission.

Third, digital signatures are different.

1. Symmetric encryption: Symmetric encryption cannot be used for digital signature and digital authentication.

2. Asymmetric encryption: Asymmetric encryption can be used for digital signature and digital authentication.