unicode - MD5 Hashing in Delphi 2009

Question

In borland delphi 7 and even in delphi 2007 everything worked, but in delphi 2009 it just returns the wrong hash!

I use wcrypt2 script (http://pastebin.com/m2f015cfd)

Just have a look:

string : "123456"

hash:

Delphi 7 : "e10adc3949ba59abbe56e057f20f883e" - real hash.
Delphi 2007 : "e10adc3949ba59abbe56e057f20f883e" - real hash too.
And... Delphi 2009 : "5fa285e1bebe0a6623e33afc04a1fbd5" - WTF??

I've tried a lot of md5 scripts, but delphi 2009 does the same with all of them. Any help? Thanks.

Answer 1

Your library is not Unicode aware. Just passing it an AnsiString won't be enough because it probably uses strings internally to store data.

You could try to update that library, wait for the author to update it, or just use the MessageDigest_5.pas that ships with Delphi 2009. It is in the sourceWin32soapwsdlimporter folder, which you will need to either add to your path, or explicitly include it in your project.

Here is some sample code using it in Delphi 2009:

uses Types, MessageDigest_5;

procedure TForm16.Edit1Change(Sender: TObject);
var
  MD5: IMD5;
begin
  MD5 := GetMD5;
  MD5.Init;
  MD5.Update(TByteDynArray(RawByteString(Edit1.Text)), Length(Edit1.Text));
  Edit2.Text := LowerCase(MD5.AsString);
end;

And you are in business:

MD5(123456) = e10adc3949ba59abbe56e057f20f883e

You could wrap it in a simple function call if you wanted to. It is important you cast to a RawByteString before casting to a TByteDynArray since the RawByteString cast drops all the extra Unicode characters. Granted if the edit contains Unicode characters then you could end up with bad data.

Keep in mind that GetMD5 is returning an interface, so it is reference counted, etc.

Merry Christmas!