Binary Data in Delphi

Some Chilkat ActiveX methods accept binary byte arrays and/or return binary byte arrays. In Delphi, these are OleVariant’s. The CkData object, found in the ChilkatUtil.dll, can be used as a helper to pass binary data to and receive the binary data results from these methods.

ChilkatUtil.dll can be downloaded from http://www.chilkatsoft.com/preRelease/ChilkatUtil.zip

Here is an RSA ActiveX example that loads RSA binary encrypted data from a file, decrypts it and saves the binary output to a file. The point of this example is to show how the CkData object is instantiated, and how it can be used to load data from a file, save it to a file, pass it to a method, and receive the binary data returned by a method:

unit Unit1;
	
interface
	
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls,
  CHILKATRSALib_TLB, CHILKATUTILLib_TLB;
	
type
  TForm1 = class(TForm)
    Button1: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
	
var
  Form1: TForm1;
	
implementation
	
{$R *.dfm}
	
procedure TForm1.Button1Click(Sender: TObject);
var
rsa: TChilkatRsa;
<strong>encData: TCkData;</strong>
<strong>decData: TCkData;</strong>
	
success: Integer;
privateKey: String;
	
begin
rsa := TChilkatRsa.Create(Self);
	
// Create the CkData objects:
<strong>encData := TCkData.Create(Self);</strong>
<strong>decData := TCkData.Create(Self);</strong>
	
success := rsa.UnlockComponent(’Anything for 30-day trial’);
if (success <> 1) then
  begin
    ShowMessage(’RSA component unlock failed’);
  end;
	
// Omitting the private key, which would typically be an XML string…
  privateKey := ‘…’;
	
rsa.ImportPrivateKey(privateKey);
	
// Load a binary file into encData
encData.LoadFile(’rsa_encrypted_data.dat’);
	
// Pass the contents of encData to DecryptBytes, and load the result into decData
decData.LoadBinary(rsa.DecryptBytes(encData.GetBinary(),1));
	
// Save the decrypted data to a file:
decData.SaveToFile(’decrypted_data.dat’);