Pascal (Lazarus/Delphi)

Google Authenticator Algorithm

See more Encryption Examples

Example code implementing the Google Authenticator algorithm. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Crypt2;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  secretBase32: string;
  crypt: TCrypt2;
  otp: string;

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 := TCrypt2.Create;
  otp := crypt.Totp(secretBase32,'base32','0','',30,6,-1,'sha1');

  WriteLn('6-digit decimal token = ' + otp);


  crypt.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.