Hash of a file

Code to determine a file hash. It returns an unique id from a file. The idea is to read the file in binary mode and calculate an MD5 hash.

md5 calculation (source)

protected internal string MD5HashString(string sTextToHash)
   {
     MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
     byte[] byValue;
      byte[] byHash;

      // Neues CryptoServiceProvider Objekt erzeugen
      byValue = System.Text.Encoding.UTF8.GetBytes(sTextToHash);
      // Berechne den Hash und schreibe ein Array von Bytes zurück
      byHash = md5.ComputeHash(byValue);
      // Provider löschen
      md5.Clear();
      // Gibt einen Base 64 codierten String mit dem Hashwert zurück
      return Convert.ToBase64String(byHash);
    }

full example

#region . hashing methods

private static string CalculateHashFromFile(string filename)
{
	// hash generation from file

	// read file bytes
	byte[] bytes = File.ReadAllBytes(filename);

	// md5 calculation
	MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
	byte[] output = md5.ComputeHash(bytes);
	string hash = Convert.ToBase64String(output);

	// returning
	return hash;
}

#endregion