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Language: Design Patterns
Expertise: Beginner

Oct 30, 1998

Question:
How do you protect an application with a password and store it in the application's exe-file?

Answer:
You'd have to hard code the password in. Then in the FormCreate method of your main form, you'd do something like this:

procedure TForm1.FormCreate(Sender: TObject);
var
  pwrd : String;
  PassOK : Boolean;
begin
  Counter := 1;
  PassOK := False;
  while (Counter < 4) do begin
    InputQuery('Type in a password',
               'You have ' + IntToStr(4 - Counter) + ' tries left',
               pwrd);
    if (pwrd = 'MyPassword') then begin
      PassOK := True;
      Break;
    end;
      Inc(Counter);
  end;

  if NOT PassOK then begin
    ShowMessage('Exceeded maximum number of tries. ' +
                'Press OK to terminate.');
    Application.Terminate;
  end;
end;

This simple password validation gives the user three tries to come up with the correct password. You could be more elaborate by using a resource file with a string resource that is read at run time.