這裏采用的加解密使用base64轉碼方法，ECB模式，PKCS5Padding填充，密碼必須是16位，否則會報錯！

　　模式：Java的ECB對應C#的System.Security.Cryptography.CipherMode.ECB

　　填充方法：Java的PKCS5Padding對應C#System.Security.Cryptography.PaddingMode.PKCS7

　　Java和C#版的加解密是互通的，也就是能相互加解密，編碼明確指定了采用UTF-8，有需要其他編碼方法的請自行擴展

Java版

package nb.tmall.util;

import java.security.NoSuchAlgorithmException;
 
import java.security.SecureRandom;

import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;

import sun.misc.*;

@SuppressWarnings("restriction")
public class EncryptUtil {

    public static String aesEncrypt(String str, String key) throws Exception {
        if (str == null || key == null) return
 
 null;
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(key.getBytes("utf-8"), "AES"));
        byte[] bytes = cipher.doFinal(str.getBytes("utf-8"));
        return new BASE64Encoder().encode(bytes);
    }

    public static
 
 String aesDecrypt(String str, String key) throws Exception {
        if (str == null || key == null) return null;
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(key.getBytes("utf-8"), "AES"));
        byte[] bytes = new BASE64Decoder().decodeBuffer(str);
        bytes = cipher.doFinal(bytes);
        return new String(bytes, "utf-8");
    }
}

C#版

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

namespace CSharp.Util.Security
{
   
        /// <summary>
        ///  AES 加密
        /// </summary>
        /// <param name="str"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public static string AesEncrypt(string str, string key)
        {
            if (string.IsNullOrEmpty(str)) return null;
            Byte[] toEncryptArray = Encoding.UTF8.GetBytes(str);

            System.Security.Cryptography.RijndaelManaged rm = new System.Security.Cryptography.RijndaelManaged
            {
                Key = Encoding.UTF8.GetBytes(key),
                Mode = System.Security.Cryptography.CipherMode.ECB,
                Padding = System.Security.Cryptography.PaddingMode.PKCS7
            };

            System.Security.Cryptography.ICryptoTransform cTransform = rm.CreateEncryptor();
            Byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

            return Convert.ToBase64String(resultArray, 0, resultArray.Length);
        }

        /// <summary>
        ///  AES 解密
        /// </summary>
        /// <param name="str"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public static string AesDecrypt(string str, string key)
        {
            if (string.IsNullOrEmpty(str)) return null;
            Byte[] toEncryptArray = Convert.FromBase64String(str);

            System.Security.Cryptography.RijndaelManaged rm = new System.Security.Cryptography.RijndaelManaged
            {
                Key = Encoding.UTF8.GetBytes(key),
                Mode = System.Security.Cryptography.CipherMode.ECB,
                Padding = System.Security.Cryptography.PaddingMode.PKCS7
            };

            System.Security.Cryptography.ICryptoTransform cTransform = rm.CreateDecryptor();
            Byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

            return Encoding.UTF8.GetString(resultArray);
        }
    }
}

Java、C#雙語版配套AES加解密示例