1. Information digest refers to the value calculated from the entire file as the digital signature object. Comparing the information summary calculated from the entire file can prove that the content of the file has not been tampered with.
2. Text data is composed of characters, and each character is assigned a number, which is called "character encoding".
3. Character sets generally include: ASCII character set, JIS character set, Shift-JIS character set, EUS character set, and Unicode character set.
4. Unencrypted text data is called "plaintext", and vice versa is "ciphertext".
5. The process of converting plaintext into ciphertext is "encryption", and vice versa is "decryption".
6. The number used for encryption and decryption is called the "key".
7. One of the encryption methods: XOR the code of each character with the key (logical exclusive OR operation) to convert the plaintext into ciphertext.
8. Generally, encryption technology with one key is called symmetric key encryption technology, also known as "secret key encryption technology". This encryption technology uses keys with the same value in the encryption and decryption processes.
9. Asymmetric encryption technology, also known as "public key encryption technology", uses two sets of values, one is the public key and the other is the private key.
10. Key creation steps
