AES加解密（C#和JAVA互通）

对接接口中遇到一个棘手的问题：甲方使用java开发，通过AES加密数据，我方使用C#开发，Java的代码和C#的代码无法互通。

        /// <summary>
        /// AES加密（128位，密码模式ECB，填充类型PKCS5Padding或者PKCS7Padding。注：ECB模式不需要初始化向量iv。）
        /// </summary>
        /// <param name="str"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public static string AES_Encrypt(string str, string key)
        {
            if (string.IsNullOrEmpty(str)) return null;
            Byte[] toEncryptArray = Encoding.UTF8.GetBytes(str);

            RijndaelManaged rm = new RijndaelManaged
            {
                Key = Convert.FromBase64String(key),
                Mode = CipherMode.ECB,
                Padding = PaddingMode.PKCS7
            };

            ICryptoTransform cTransform = rm.CreateEncryptor();
            Byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
            StringBuilder ret = new StringBuilder();
            foreach (byte b in resultArray.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            return Convert.ToBase64String(resultArray, 0, resultArray.Length);
        }

        /// <summary>
        /// AES解密（128位，密码模式ECB，填充类型PKCS5Padding或者PKCS7Padding。注：ECB模式不需要初始化向量iv。）
        /// </summary>
        /// <param name="toDecrypt"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        public static string AES_Decrypt(string toDecrypt, string key)
        {
            byte[] keyArray = Convert.FromBase64String(key); //将TestGenAESByteKey类输出的字符串转为byte数组
            byte[] toEncryptArray = Convert.FromBase64String(toDecrypt);
            RijndaelManaged rDel = new RijndaelManaged();
            rDel.Key = keyArray;
            rDel.Mode = CipherMode.ECB;        //必须设置为ECB
            rDel.Padding = PaddingMode.PKCS7;  //必须设置为PKCS7
            ICryptoTransform cTransform = rDel.CreateDecryptor();
            byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
            return UTF8Encoding.UTF8.GetString(resultArray);

        }