private string MD5Calc(string str)
{
string s = "";
MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
byte[] bytes = System.Text.Encoding.UTF8.GetBytes(str);
byte[] buffer = md5.ComputeHash(bytes);
for (int i = 0; i < buffer.Length; i++)
{
s += buffer[i].ToString("X2");
}
return s;
}