C#-MD5

//字符串
 try
{
 string inputM = "", outputM = "null";
 byte[] result = Encoding.Default.GetBytes(inputM);    //tbPass为输入密码的文本框
 MD5 md5 = new MD5CryptoServiceProvider();
 byte[] output = md5.ComputeHash(result);
 outputM = BitConverter.ToString(output).Replace("-", "");
 MessageBox.Show(outputM);
}
catch{}


文件
try
{
         FileStream file = new FileStream(fileName, FileMode.Open);
         MD5 md5 = new MD5CryptoServiceProvider();
         byte[] retVal = md5.ComputeHash(file);
         file.Close();
         StringBuilder sb = new StringBuilder();
         for (int i = 0; i < retVal.Length; i++)
         {
              sb.Append(retVal[i].ToString("x2"));
         }
         return sb.ToString();
}
catch (Exception ex)
{
       throw new Exception("GetMD5HashFromFile() fail,error:" + ex.Message);
}