public static string MD5Encrypt(string str)
{
MD5 md5 = MD5.Create();
byte[] fromData = Encoding.Default.GetBytes(str);
byte[] targetData = md5.ComputeHash(fromData);
StringBuilder byteString = new StringBuilder();
for (int i = 0; i < targetData.Length; i++)
{
byteString.AppendFormat("{0:x2}", targetData[i]);
}
return byteString.ToString();
}