1. Hash calculation

is to convert an input of any length into a fixed-length output through a hash algorithm, and the output is the hash value. To put it simply, it is a summary function that compresses any length to a fixed length.

2. Public key and private key

(1) Private key

Private key encryption is also called symmetric encryption, which is used to encrypt and decrypt information. The same key is used to encrypt and decrypt data. The advantage is that the encryption/decryption speed is fast and it is suitable for encrypting and decrypting large amounts of data. The disadvantage is that it is difficult to manage.

Single-key encryption method refers to using the same secret key for encryption and decryption, also known as symmetric encryption and secret-key encryption. Since both encryption and decryption parties use the same encryption method, this method is inherently insecure.

(2) Public key

Asymmetric encryption. This encryption method requires two secret keys: a public key and a private key. The public key and the private key are in pairs. Encryption with a certain private key requires the corresponding public key to decrypt; encryption with a certain public key requires the corresponding private key to decrypt.

The asymmetric encryption method has good confidentiality, but encryption and decryption take a long time and are slow.

3. Signature verification

For the received message, a signature process is performed locally, and the signature generated by the local signature is compared with the received signature value. If they are the same, the signature verification is successful.

4. Digital envelope encryption

For sensitive information, use a randomly generated private key for symmetric encryption. At the same time, in order to ensure the security of the stacked secret key, a public key certificate is used to asymmetrically encrypt the symmetric private key to obtain a digital envelope.

5. Digital envelope decryption

Perform the reverse operation of digital envelope encryption on the received digital envelope to obtain the plaintext of sensitive information, which is digital envelope decryption.

6. Digital certificate

A series of data that marks the identity of each communicating party in network communication, similar to ID cards in real life. It is issued by an authoritative organization. People can use it to identify each other on the Internet. The certificate format follows the ITUTX.509 international standard.