C#.NET与JAVA互通之AES加密解密V2024

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本文主要讨论了C#和Java中的AES加密解密的使用方法及其注意点。文章首先概述了C#中AesUtil类中的加解密方法，包括CBC模式和ECB模式的加密解密。然后，对Java中的AesUtil类也进行了相应的介绍，并对比了两者的差异。 1. **C# AES 加密解密** - C# 中的AesUtil类提供了丰富的AES加密解密方法，包括CBC模式和ECB模式。 - 明文转换成byte数组时，双方需约定编码方式。 - 密文转成字符串时，也是双方协议好的编码方式。 - 对于不同的密钥长度(AES128, AES256)，C# 有专门的实现方法。 2. **Java AES 加密解密** - Java 中的AesUtil类同样实现了AES加密解密，但略有不同。 - 与C#类似，密文转成字符串也是通过编码方式实现的。 - Java 使用PKCS5Padding填充方式，而C# 使用PKCS7Padding。 3. **AES KEY 变种** - 文章还提到了AES KEY可以有不同的变体，例如MD5哈希后的值，或者其他算法处理后的密钥。 - 在C#中，可以通过截取前16位作为AES128，或者进行MD5哈希后得到AES256。总的来说，本文详细介绍了C#和Java中AES加密解密的处理流程和注意问题，为开发者在使用这两种语言时提供了一定的参考。

正文

视频：

注意点：

1. KEY 和 IV 从字符串转byte数组时，双方要约定好编码，一般是UTF8。

2.明文从字符串转byte数组时，双方要约定好编码，一般是UTF8，也可以GB2312，但不能Encoding.Default。

3.加密后的结果，从byte数组转字符串时，双方要约定好编码，一般是Base64字符串。

4.NET 的PKCS7Padding 对应 JAVA 的：PKCS5Padding
5. AES128指的是密钥长度为16个字符串（16Byte * 8 = 128 bit），AES256指的是密钥长度为32个字符串（32Byte * 8 = 256 bit）。

6.AES KEY 的变种（MD5 HASH 后，正好是AES256，或截取前16位作为AES128）

一、C#.NET：

AesUtil：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;

namespace CommonUtils
{
    /// <summary>
    /// AES 工具类，2024-06-07，runliuv。
    /// </summary>
    public static class AesUtil
    {

        /// <summary>
        /// AES CBC 解密
        /// </summary>
        /// <param name="decryptStr">要解密的串,base64字符串</param>
        /// <param name="aesKey">密钥</param>
        /// <param name="aesIV">IV</param>
        /// <returns></returns>
        public static string AesDecryptCBC(string decryptStr, string aesKey, string aesIV)
        {

            byte[] byteKEY = Encoding.UTF8.GetBytes(aesKey);
            byte[] byteIV = Encoding.UTF8.GetBytes(aesIV);

            byte[] byteDecrypt = Convert.FromBase64String(decryptStr);

            var _aes = new RijndaelManaged();
            _aes.Padding = PaddingMode.PKCS7;
            _aes.Mode = CipherMode.CBC;

            _aes.Key = byteKEY;
            _aes.IV = byteIV;

            var _crypto = _aes.CreateDecryptor();
            byte[] decrypted = _crypto.TransformFinalBlock(
                byteDecrypt, 0, byteDecrypt.Length);

            _crypto.Dispose();

            return Encoding.UTF8.GetString(decrypted);
        }

        /// <summary>
        /// AES CBC 解密，输入输出都是byte[]，方便用各种编码转换成字符串
        /// </summary>
        /// <param name="byteDecrypt"></param>
        /// <param name="byteKEY"></param>
        /// <param name="byteIV"></param>
        /// <returns></returns>
        public static byte[] AesDecryptCBC(byte[] byteDecrypt, byte[] byteKEY, byte[] byteIV)
        {

            var _aes = new RijndaelManaged();
            _aes.Padding = PaddingMode.PKCS7;
            _aes.Mode = CipherMode.CBC;

            _aes.Key = byteKEY;
            _aes.IV = byteIV;

            var _crypto = _aes.CreateDecryptor();
            byte[] decrypted = _crypto.TransformFinalBlock(
                byteDecrypt, 0, byteDecrypt.Length);

            _crypto.Dispose();

            return decrypted;
        }

        /// <summary>
        /// AES CBC 加密，输出base64字符串。
        /// </summary>
        /// <param name="content"></param>
        /// <param name="aesKey"></param>
        /// <param name="aesIV"></param>
        /// <returns></returns>
        public static string AesEncryptCBC(string content, string aesKey, string aesIV)
        {

            byte[] byteKEY = Encoding.UTF8.GetBytes(aesKey);
            byte[] byteIV = Encoding.UTF8.GetBytes(aesIV);

            byte[] byteContnet = Encoding.UTF8.GetBytes(content);

            var _aes = new RijndaelManaged();
            _aes.Padding = PaddingMode.PKCS7;
            _aes.Mode = CipherMode.CBC;

            _aes.Key = byteKEY;
            _aes.IV = byteIV;

            var _crypto = _aes.CreateEncryptor();
            byte[] decrypted = _crypto.TransformFinalBlock(
                byteContnet, 0, byteContnet.Length);

            _crypto.Dispose();

            return Convert.ToBase64String(decrypted);
        }

        /// <summary>
        /// AES CBC 加密，输入输出都是byte[]，方便用各种编码转换成字符串
        /// </summary>
        /// <param name="byteContnet"></param>
        /// <param name="byteKEY"></param>
        /// <param name="byteIV"></param>
        /// <returns></returns>
        public static byte[] AesEncryptCBC(byte[] byteContnet, byte[] byteKEY, byte[] byteIV)
        {

            var _aes = new RijndaelManaged();
            _aes.Padding = PaddingMode.PKCS7;
            _aes.Mode = CipherMode.CBC;

            _aes.Key = byteKEY;
            _aes.IV = byteIV;

            var _crypto = _aes.CreateEncryptor();
            byte[] decrypted = _crypto.TransformFinalBlock(
                byteContnet, 0, byteContnet.Length);

            _crypto.Dispose();

            return decrypted;
        }


        public static string AesEncryptECB(string content, string aesKey)
        {

            byte[] byteKEY = Encoding.UTF8.GetBytes(aesKey);

            byte[] byteContnet = Encoding.UTF8.GetBytes(content);

            var _aes = new RijndaelManaged();
            _aes.Padding = PaddingMode.PKCS7;
            _aes.Mode = CipherMode.ECB;

            _aes.Key = byteKEY;
            

            var _crypto = _aes.CreateEncryptor();
            byte[] decrypted = _crypto.TransformFinalBlock(
                byteContnet, 0, byteContnet.Length);

            _crypto.Dispose();

            return Convert.ToBase64String(decrypted);
        }

        public static string AesDecryptECB(string decryptStr, string aesKey)
        {

            byte[] byteKEY = Encoding.UTF8.GetBytes(aesKey);

            byte[] byteDecrypt = Convert.FromBase64String(decryptStr);

            var _aes = new RijndaelManaged();
            _aes.Padding = PaddingMode.PKCS7;
            _aes.Mode = CipherMode.ECB;

            _aes.Key = byteKEY;

            var _crypto = _aes.CreateDecryptor();
            byte[] decrypted = _crypto.TransformFinalBlock(
                byteDecrypt, 0, byteDecrypt.Length);

            _crypto.Dispose();

            return Encoding.UTF8.GetString(decrypted);
        }

    }
}

HashUtil

using System;
using System.Collections.Generic;
using System.Linq;
using System.Security.Cryptography;
using System.Text;

namespace CommonUtils
{
    public static class HashUtil
    {

        public static string GetMd5(string src)
        {
            MD5 md =   MD5.Create();
            byte[] bytes = Encoding.UTF8.GetBytes(src);
            byte[] buffer2 = md.ComputeHash(bytes);
            string str = "";
            for (int i = 0; i < buffer2.Length; i++)
            {
                str = str + buffer2[i].ToString("x2");
            }
            return str;

        }

        public static IDictionary<string, string> ModelToDic<T1>(T1 cfgItem)
        {
            IDictionary<string, string> sdCfgItem = new Dictionary<string, string>();

            System.Reflection.PropertyInfo[] cfgItemProperties = cfgItem.GetType().GetProperties(System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public);
            foreach (System.Reflection.PropertyInfo item in cfgItemProperties)
            {
                string name = item.Name;
                object value = item.GetValue(cfgItem, null);
                if (value != null && (item.PropertyType.IsValueType || item.PropertyType.Name.StartsWith("String")) && !string.IsNullOrWhiteSpace(value.ToString()))
                {
                    sdCfgItem.Add(name, value.ToString());
                }
            }

            return sdCfgItem;
        }

        public static IDictionary<string, string> AsciiDictionary(IDictionary<string, string> sArray)
        {
            IDictionary<string, string> asciiDic = new Dictionary<string, string>();
            string[] arrKeys = sArray.Keys.ToArray();
            Array.Sort(arrKeys, string.CompareOrdinal);
            foreach (var key in arrKeys)
            {
                string value = sArray[key];
                asciiDic.Add(key, value);
            }
            return asciiDic;
        }

        public static string BuildQueryString(IDictionary<string, string> sArray)
        {

            //拼接 K=V&A=B&c=1 这种URL

            StringBuilder sc = new StringBuilder();

            foreach (var item in sArray)
            {
                string name = item.Key;
                string value = item.Value;
                if (!string.IsNullOrWhiteSpace(value))
                {
                    sc.AppendFormat("{0}={1}&", name, value);
                }

            }

            string fnlStr = sc.ToString();
            fnlStr = fnlStr.TrimEnd('&');

            return fnlStr;
        }

    }
}

.NET 使用：

using CommonUtils;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    internal class Program
    {
        static void Main(string[] args)
        {
            try
            {
                //.NET 的PKCS7 对应 JAVA 的：PKCS5Padding
                TestAesCbc();

                TestAesECB();

                //JAVA加密，.NET 解密
                string javaStr = "FfRdTUVCFSknpYNXoMHQOAQNEqkHY1uU19u/3wWH6Js=";
                Console.WriteLine("JAVA加密后的字符串：" + javaStr);
                string aesKey = "1234567890123456";//AES KEY 与 JAVA 保持一致
                string decryptedStr = AesUtil.AesDecryptECB(javaStr, aesKey);
                Console.WriteLine("自加，自解：" + decryptedStr);


                //有的AES加密，不是直接把字符串当KEY使用，而是把原密钥 MD5 HASH后，作为AES 的KEY。
                TestAesKeyTrap();
            }
            catch (Exception ex)
            {
                Console.WriteLine("ex！" + ex.Message);
            }
            Console.WriteLine("结束！");
            Console.ReadKey();
        }

        static void TestAesCbc()
        {
            Console.WriteLine("-- TestAesCbc --" );
            string aesKey = "1234567890123456";//16位或32位
            string aesIV = "abcdefghABCDEFGH";

            string aa = "这边是 .net aes 加密";
            Console.WriteLine("待加密字符串：" + aa);
            string encryptedStr = AesUtil.AesEncryptCBC(aa, aesKey, aesIV);
            Console.WriteLine("加密字符串：" + encryptedStr);
            //自加，自解
            string decryptedStr = AesUtil.AesDecryptCBC(encryptedStr, aesKey, aesIV);
            Console.WriteLine("自加，自解：" + decryptedStr);
        }

        static void TestAesECB()
        {
            Console.WriteLine("-- TestAesECB --");

            string aesKey = "1234567890123456";//16位或32位

            string aa = ".net aes 加密";
            Console.WriteLine("待加密字符串：" + aa);
            string encryptedStr = AesUtil.AesEncryptECB(aa, aesKey);
            Console.WriteLine("加密字符串：" + encryptedStr);
            //自加，自解
            string decryptedStr = AesUtil.AesDecryptECB(encryptedStr, aesKey);
            Console.WriteLine("自加，自解：" + decryptedStr);
        }

        /// <summary>
        /// AES KEY 的变种（MD5 HASH 后，正好是AES256，或截取前16位作为AES128）
        /// </summary>
        static void TestAesKeyTrap()
        {
            Console.WriteLine("-- TestAesECB --");

            string orgKey = "HelloWorld";//不够16位或32位
            //string aesKey = "HelloWorld";//不够16位或32位

            string aesKey = HashUtil.GetMd5(orgKey).ToLower().Substring(16);
            Console.WriteLine("GetMd5后的长度：" + aesKey.Length.ToString());

            string aa = ".net aes 加密";
            Console.WriteLine("待加密字符串：" + aa);
            string encryptedStr = AesUtil.AesEncryptECB(aa, aesKey);
            Console.WriteLine("加密字符串：" + encryptedStr);
            //自加，自解
            string decryptedStr = AesUtil.AesDecryptECB(encryptedStr, aesKey);
            Console.WriteLine("自加，自解：" + decryptedStr);
        }
    }
}

二、JAVA：

AesUtil：

package org.runliuv;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;

public class AesUtil {

    private static final String charset = "UTF-8";

    /**
     * 加密
     * @param content
     * @param key
     * @param iv
     * @return
     * @throws Exception
     */
    public static String AesEncryptCBC(String content, String key, String iv)
            throws Exception {

        //明文
        byte[] contentBytes = content.getBytes(charset);

        //AES KEY
        byte[] keyBytes = key.getBytes(charset);
        SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");

        //AES IV
        byte[] initParam = iv.getBytes(charset);
        IvParameterSpec ivParameterSpec = new IvParameterSpec(initParam);

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, keySpec, ivParameterSpec);
        byte[] byEnd = cipher.doFinal(contentBytes);

        //加密后的byte数组转BASE64字符串
        String strEnd = Base64.getEncoder().encodeToString(byEnd);
        return strEnd;
    }

    /**
     * 解密
     * @param content
     * @param key
     * @param iv
     * @return
     * @throws Exception
     */
    public static String AesDecryptCBC(String content, String key, String iv)
            throws Exception {
        //反向解析BASE64字符串为byte数组
        byte[] encryptedBytes = Base64.getDecoder().decode(content);

        //AES KEY
        byte[] keyBytes = key.getBytes(charset);
        SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");

        //AES IV
        byte[] initParam = iv.getBytes(charset);
        IvParameterSpec ivParameterSpec = new IvParameterSpec(initParam);

        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, keySpec, ivParameterSpec);
        byte[] byEnd = cipher.doFinal(encryptedBytes);

        //加密后的byte数组直接转字符串
        String strEnd = new String(byEnd, charset);
        return strEnd;
    }

    public static String AesEncryptECB(String content, String key)
            throws Exception {

        //明文
        byte[] contentBytes = content.getBytes(charset);

        //AES KEY
        byte[] keyBytes = key.getBytes(charset);
        SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");

        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, keySpec);
        byte[] byEnd = cipher.doFinal(contentBytes);

        //加密后的byte数组转BASE64字符串
        String strEnd = Base64.getEncoder().encodeToString(byEnd);
        return strEnd;
    }

    public static String AesDecryptECB(String content, String key)
            throws Exception {
        //反向解析BASE64字符串为byte数组
        byte[] encryptedBytes = Base64.getDecoder().decode(content);

        //AES KEY
        byte[] keyBytes = key.getBytes(charset);
        SecretKeySpec keySpec = new SecretKeySpec(keyBytes, "AES");

        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, keySpec);
        byte[] byEnd = cipher.doFinal(encryptedBytes);

        //加密后的byte数组直接转字符串
        String strEnd = new String(byEnd, charset);
        return strEnd;
    }

}

java使用：

package org.runliuv;

/**
 * Hello world!
 *
 */
public class App 
{
    public static void main( String[] args )
    {

        try
        {
            TestAesCbc();

            TestAesECB();

            //.net aes cbc 加，JAVA 解密
            String netStr="Mrs6Ufo2Y4ulWiksFSWFnUNKVSO5COruAlgQ5ws7FL0=";
            System.out.println("-- .net 加密后的内容：" + netStr);
            String aesKey = "1234567890123456";//与.net 保持一致
            String aesIV = "abcdefghABCDEFGH";//与.net 保持一致

            String decryptedStr = AesUtil.AesDecryptCBC(netStr, aesKey, aesIV);
            System.out.println(".net aes cbc 加，JAVA 解密：" + decryptedStr);

        }catch (Exception ex){

            System.out.println( "ex！"+ex.getMessage() );
        }
        System.out.println( "结束！" );
    }

    static void  TestAesCbc(){

        try {
            System.out.println("-- TestAesCbc --" );

            //16位 (32位,jdk8 老版本，需要放JAR包才支持32位的)
            String aesKey = "1234567890123456";
            String aesIV = "abcdefghABCDEFGH";

            String aa = "java aes 加密，2024-06-07。";
            System.out.println("待加密字符串：" + aa);
            String encryptedStr = AesUtil.AesEncryptCBC(aa, aesKey, aesIV);
            System.out.println("加密字符串：" + encryptedStr);
            //自加，自解
            String decryptedStr = AesUtil.AesDecryptCBC(encryptedStr, aesKey, aesIV);
            System.out.println("自加，自解：" + decryptedStr);

        }catch (Exception ex){

            System.out.println( "ex！"+ex.getMessage() );
        }

    }

    static void  TestAesECB(){

        try {
            System.out.println("-- TestAesECB --" );

            //16位 (32位,jdk8 老版本，需要放JAR包才支持32位的)
            String aesKey = "1234567890123456";

            String aa = "java aes 加密，2024-06-07。";
            System.out.println("待加密字符串：" + aa);
            String encryptedStr = AesUtil.AesEncryptECB(aa, aesKey);
            System.out.println("加密字符串：" + encryptedStr);
            //自加，自解
            String decryptedStr = AesUtil.AesDecryptECB(encryptedStr, aesKey);
            System.out.println("自加，自解：" + decryptedStr);

        }catch (Exception ex){

            System.out.println( "ex！"+ex.getMessage() );
        }

    }
}