哈希算法：完整性、密码存储与数字签名

import crypto from 'crypto';

function calculateSHA256(input) {
  const hash = crypto.createHash('sha256');
  hash.update(input);
  return hash.digest('hex');
}

const data = '你好, 世界!';
const hash = calculateSHA256(data);
console.log(`SHA-256 哈希值: ${hash}`);

import hashlib

def calculate_sha256(input_string):
    sha256_hash = hashlib.sha256()
    sha256_hash.update(input_string.encode('utf-8'))
    return sha256_hash.hexdigest()

data = "你好, 世界!"
hashed_data = calculate_sha256(data)
print(f"SHA-256 哈希值: {hashed_data}")

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class HashingExample {
    public static String calculateSHA256(String input) {
        try {
            MessageDigest digest = MessageDigest.getInstance("SHA-256");
            byte[] encodedhash = digest.digest(input.getBytes(StandardCharsets.UTF_8));
            return bytesToHex(encodedhash);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    private static String bytesToHex(byte[] hash) {
        StringBuilder hexString = new StringBuilder(2 * hash.length);
        for (byte b : hash) {
            String hex = Integer.toHexString(0xff & b);
            if (hex.length() == 1) {
                hexString.append('0');
            }
            hexString.append(hex);
        }
        return hexString.toString();
    }

    public static void main(String[] args) {
        String data = "你好, 世界!";
        String sha256 = calculateSHA256(data);
        System.out.println("SHA-256 哈希值: " + sha256);
    }
}