If the input contents are exactly the same, then encryption with SHA-256 function can always get the same final encryption result. Officially, SHA-256 function has these characteristics, which makes us interested in it. Because in the following content, we have to apply the concept of key frequently, so let's summarize the essence of it here.
Introduction:
The key can be simply understood as the input parameter of an algorithm, for example, there is a string number of 520 13 14, so we need to encrypt it now, where f can be understood as our encryption algorithm, that is, SHA-256 algorithm, and 2 here can be simply considered as our encryption key.
If the encryption key is different from the decryption key, then this encryption method is called asymmetric encryption. In the asymmetric encryption method, the encryption key is called the private key and the decryption key is called the public key. Only the encryptor knows the private key, and the public key is public, which can be decrypted by others.
The public key is generally calculated by inputting the private key into an algorithm. The public key can be derived from the private key, but not vice versa. Therefore, we can optimize the digital signature we discussed earlier, but as you can surely guess, it is not enough. A front-end should not only meet the requirements of communication, but also meet the important characteristics of authentication.