AES加密和Base64混合加密

/// <summary>
        /// AES加密方法(AES加密和Base64混合加密)
        /// </summary>
        /// <param name="toEncrypt"></param>
        /// <returns></returns>
        public static string Encrypt(string content, string InsureKey)
        {
            string toEncrypt = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(content, "MD5").ToLower();

            //指定InsureKey做MD5加密并作截取(C#截取8到16)获得加密的key作为密钥
            string key = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(InsureKey, "MD5").Substring(8, 16).ToLower();

            byte[] keyArray = UTF8Encoding.UTF8.GetBytes(key);
            byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

            RijndaelManaged rDel = new RijndaelManaged();
            rDel.Key = keyArray;
            rDel.Mode = CipherMode.ECB;
            rDel.Padding = PaddingMode.PKCS7;

            ICryptoTransform cTransform = rDel.CreateEncryptor();
            byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
            return Convert.ToBase64String(resultArray).Replace("+", "%2B");
        }