DESCryptoServiceProvider 加密解密

public static class Extend
{
        //注意：这里的密钥sKey必须能转为8个byte，即输入密钥为8半角个字符或者4个全角字符或者4个汉字的字符串
        public static string strKey = "bingTest";
        public static string strIV = "strTstIV";

        // 加密
        public static string Encrypt(string str)
        {
            byte[] buffer = Encoding.UTF8.GetBytes(str);
            MemoryStream ms = new MemoryStream();
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            CryptoStream encStream = new CryptoStream(ms, des.CreateEncryptor(Encoding.UTF8.GetBytes(strKey), Encoding.UTF8.GetBytes(strIV)), CryptoStreamMode.Write);
            encStream.Write(buffer, 0, buffer.Length);
            encStream.FlushFinalBlock();
            //加密之后转为Base64字符串
            string res64 = Convert.ToBase64String(ms.ToArray());
           //将Base64字符串转为byte数组
            var res64Tobt = Convert.FromBase64String(res64);
            string result = string.Empty;
            //byte数组转16进制字符串，如果加密的字符串需要在URL中传输的话，不然Base64字符串有特殊字符会被浏览器去掉，例如：+会变为空格
            for (int i = 0; i < res64Tobt.Length; i++)
            {
                result += string.Format("{0:x2}", res64Tobt[i]);
            }
            return result;
        }

        // 解密
        public static string Decrypt(string str)
        {
            string result = string.Empty;
            int str_lth = str.Length / 2;
            byte[] strbt = new byte[str_lth];
            //16进制字符串转byte数组
            for (int i = 0; i < str_lth; i++)
            {
                strbt[i] = Convert.ToByte(str.Substring(i * 2, 2), 16);
            }
            //byte数组转Base64字符串
            string bas64 = Convert.ToBase64String(strbt);
            //将Base64字符串转为byte数组
            byte[] buffer = Convert.FromBase64String(bas64);
            MemoryStream ms = new MemoryStream();
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            CryptoStream encStream = new CryptoStream(ms, des.CreateDecryptor(Encoding.UTF8.GetBytes(strKey), Encoding.UTF8.GetBytes(strIV)), CryptoStreamMode.Write);
            encStream.Write(buffer, 0, buffer.Length);
            encStream.FlushFinalBlock();
            result = Encoding.UTF8.GetString(ms.ToArray());
            return result;
        }
    }