各种语言MD5计算方法

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Python

import hashlib

# 字符串
s = "hello".encode("utf-8")
print(hashlib.md5(s).hexdigest())

# 文件
def md5_file(path, bufsize=8192):
    h = hashlib.md5()
    with open(path, "rb") as f:
        for chunk in iter(lambda: f.read(bufsize), b""):
            h.update(chunk)
    return h.hexdigest()

# print(md5_file("path/to/file"))

Node.js (运行时)

const crypto = require('crypto');

// 字符串
const s = 'hello';
console.log(crypto.createHash('md5').update(s, 'utf8').digest('hex'));

// 文件
const fs = require('fs');
function md5File(path) {
  const hash = crypto.createHash('md5');
  return new Promise((resolve, reject) => {
    fs.createReadStream(path)
      .on('data', d => hash.update(d))
      .on('end', () => resolve(hash.digest('hex')))
      .on('error', reject);
  });
}
// md5File('path/to/file').then(console.log);

浏览器端：Web Crypto 不支持 MD5。需用第三方库（如 SparkMD5）。

<script src="https://cdn.jsdelivr.net/npm/spark-md5@3/dist/spark-md5.min.js"></script>
<script>
  console.log(SparkMD5.hash('hello')); // 字符串
</script>

Java (JDK)

import java.security.*;
import java.nio.file.*;
import java.io.*;

public class MD5Demo {
  static String toHex(byte[] b){ StringBuilder sb=new StringBuilder(); for(byte x:b) sb.append(String.format("%02x", x)); return sb.toString(); }

  public static void main(String[] args) throws Exception {
    // 字符串
    MessageDigest md = MessageDigest.getInstance("MD5");
    md.update("hello".getBytes("UTF-8"));
    System.out.println(toHex(md.digest()));

    // 文件
    System.out.println(md5File(Paths.get("path/to/file")));
  }

  static String md5File(Path p) throws Exception {
    MessageDigest md = MessageDigest.getInstance("MD5");
    try (InputStream is = Files.newInputStream(p)) {
      byte[] buf = new byte[8192];
      int n;
      while ((n = is.read(buf)) > 0) md.update(buf, 0, n);
    }
    return toHex(md.digest());
  }
}

C# (.NET)

using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;

class Program {
  static void Main() {
    // 字符串
    using var md5 = MD5.Create();
    var hash = md5.ComputeHash(Encoding.UTF8.GetBytes("hello"));
    Console.WriteLine(Convert.ToHexString(hash).ToLower());

    // 文件
    // Console.WriteLine(MD5File("path/to/file"));
  }

  static string MD5File(string path){
    using var md5 = MD5.Create();
    using var fs = File.OpenRead(path);
    return Convert.ToHexString(md5.ComputeHash(fs)).ToLower();
  }
}

Go

package main

import (
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"io"
	"os"
)

func main() {
	// 字符串
	sum := md5.Sum([]byte("hello"))
	fmt.Println(hex.EncodeToString(sum[:]))

	// 文件
	// fmt.Println(md5File("path/to/file"))
}

func md5File(path string) (string, error) {
	f, err := os.Open(path)
	if err != nil { return "", err }
	defer f.Close()
	h := md5.New()
	if _, err := io.Copy(h, f); err != nil { return "", err }
	return hex.EncodeToString(h.Sum(nil)), nil
}

PHP

<?php
// 字符串
echo md5("hello"), PHP_EOL;

// 文件
// echo md5_file("path/to/file"), PHP_EOL;

Ruby

require 'digest'

# 字符串
puts Digest::MD5.hexdigest("hello")

# 文件
# puts Digest::MD5.file("path/to/file").hexdigest

Kotlin (JVM)

import java.security.MessageDigest
import java.io.FileInputStream

fun ByteArray.toHex() = joinToString("") { "%02x".format(it) }

fun main() {
    val md = MessageDigest.getInstance("MD5")
    println(md.digest("hello".toByteArray()).toHex())

    // 文件
    // println(md5File("path/to/file"))
}

fun md5File(path: String): String {
    val md = MessageDigest.getInstance("MD5")
    FileInputStream(path).use { fis ->
        val buf = ByteArray(8192)
        while (true) {
            val n = fis.read(buf)
            if (n < 0) break
            md.update(buf, 0, n)
        }
    }
    return md.digest().toHex()
}

Swift (Apple 平台，CommonCrypto)

注意：Swift 的 CryptoKit 不支持 MD5；用 CommonCrypto。

import Foundation
import CommonCrypto

func md5(_ s: String) -> String {
    let data = Data(s.utf8)
    var digest = [UInt8](repeating: 0, count: Int(CC_MD5_DIGEST_LENGTH))
    data.withUnsafeBytes { CC_MD5($0.baseAddress, CC_LONG(data.count), &digest) }
    return digest.map { String(format: "%02x", $0) }.joined()
}

print(md5("hello"))

// 文件
func md5File(url: URL) throws -> String {
    let bufSize = 8192
    var ctx = CC_MD5_CTX()
    CC_MD5_Init(&ctx)
    let fh = try FileHandle(forReadingFrom: url)
    while autoreleasepool(invoking: {
        let data = fh.readData(ofLength: bufSize)
        if data.count > 0 {
            data.withUnsafeBytes { _ = CC_MD5_Update(&ctx, $0.baseAddress, CC_LONG(data.count)) }
            return true
        } else { return false }
    }) {}
    var digest = [UInt8](repeating: 0, count: Int(CC_MD5_DIGEST_LENGTH))
    CC_MD5_Final(&digest, &ctx)
    return digest.map { String(format: "%02x", $0) }.joined()
}

Rust

// Cargo.toml 添加： md5 = "0.7"
fn main() {
    let digest = md5::compute("hello");
    println!("{:x}", digest);
}

// 文件
use std::fs::File;
use std::io::{self, Read};
fn md5_file(path: &str) -> io::Result<String> {
    let mut file = File::open(path)?;
    let mut ctx = md5::Context::new();
    let mut buf = [0u8; 8192];
    loop {
        let n = file.read(&mut buf)?;
        if n == 0 { break; }
        ctx.consume(&buf[..n]);
    }
    Ok(format!("{:x}", ctx.compute()))
}

C（基于 OpenSSL）

#include <stdio.h>
#include <string.h>
#include <openssl/md5.h>

void to_hex(const unsigned char* d, unsigned int len){
    for(unsigned int i=0;i<len;i++) printf("%02x", d[i]);
    printf("\n");
}

int main(){
    const char* s = "hello";
    unsigned char out[MD5_DIGEST_LENGTH];
    MD5((const unsigned char*)s, strlen(s), out);
    to_hex(out, MD5_DIGEST_LENGTH);
    return 0;
}

C++（基于 OpenSSL）

#include <iostream>
#include <iomanip>
#include <openssl/md5.h>
#include <string>

int main() {
    std::string s = "hello";
    unsigned char out[MD5_DIGEST_LENGTH];
    MD5(reinterpret_cast<const unsigned char*>(s.data()), s.size(), out);
    std::ios::fmtflags f(std::cout.flags());
    for (int i=0;i<MD5_DIGEST_LENGTH;i++)
        std::cout << std::hex << std::setfill('0') << std::setw(2) << (int)out[i];
    std::cout << std::endl;
    std::cout.flags(f);
    return 0;
}

Bash / Shell

# GNU/Linux
echo -n "hello" | md5sum | awk '{print $1}'

# macOS
echo -n "hello" | md5

# OpenSSL 通用
echo -n "hello" | openssl md5 | awk '{print $2}'
# 文件
# md5sum path/to/file           # Linux
# md5 path/to/file              # macOS
# openssl md5 path/to/file      # 通用

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统一校验

所有示例对字符串 "hello" 的 MD5 都应输出：

5d41402abc4b2a76b9719d911017c592