MD5加密方法

//传进要加密的字符串，返回一个MD5串，然后进行对比

        public static String GetMD5Str(String info)
        {
            try
            {
                byte[] res = System.Text.Encoding.Default.GetBytes(info);
                MD5CryptoServiceProvider md = new MD5CryptoServiceProvider();
                byte[] result = md.ComputeHash(res);
                byte[] hash = md.ComputeHash(result);
                StringBuilder sbuilder = new StringBuilder();
                for (int i = 0; i < hash.Length; i++)
                {
                    int v = hash[i] & 0xFF;
                    if (v < 16) sbuilder.Append("0");
                    sbuilder.Append(Convert.ToString(v, 16).ToUpper());
                }
                return sbuilder.ToString();
            }
            catch
            {
                return null;
            }
        }