(Delphi DLL) Google Authenticator Algorithm

Example code implementing the Google Authenticator algorithm.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Crypt2;

...

procedure TForm1.Button1Click(Sender: TObject);
var
secretBase32: PWideChar;
crypt: HCkCrypt2;
otp: PWideChar;

begin
// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// Generating TOTP Base32 Secret: 
// When you enable 2FA with a TOTP-based authenticator app, Google will provide you with a QR code
// that you can scan using the app. This QR code contains a TOTP base32 secret.
// You can also choose to view and copy the secret manually.

secretBase32 := 'JBSWY3DPEHPK3PXP';

// Do the following to calculate the 6-digit decimal Google authenticator token for a base32 secret,
// given the current system date/time.
crypt := CkCrypt2_Create();
otp := CkCrypt2__totp(crypt,secretBase32,'base32','0','',30,6,-1,'sha1');

Memo1.Lines.Add('6-digit decimal token = ' + otp);

CkCrypt2_Dispose(crypt);

end;