Pascal (Lazarus/Delphi)

Sign JSON to Create CAdES P7S Bytes

See more CAdES Examples

Demonstrates how to sign JSON using a certificate + private key from a .p12/.pfx to create a CAdES P7S byte array. 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.Cert,
  Chilkat.JsonObject,
  Chilkat.Crypt2;

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

procedure RunDemo;
var
  success: Boolean;
  crypt: TCrypt2;
  cert: TCert;
  jsonSigningAttrs: TJsonObject;
  cadesP7s: TBytes;
  originalJson: string;

begin
  success := False;

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

  crypt := TCrypt2.Create;

  cert := TCert.Create;
  success := cert.LoadPfxFile('qa_data/pfx/cert_test123.pfx','test123');
  if (success <> True) then
    begin
      WriteLn(cert.LastErrorText);
      Exit;
    end;

  //  Tell the crypt component to use this cert.
  success := crypt.SetSigningCert(cert);
  if (success <> True) then
    begin
      WriteLn(crypt.LastErrorText);
      Exit;
    end;

  //  The CadesEnabled property applies to all methods that create PKCS7 signatures. 
  //  To create a CAdES-BES signature, set this property equal to true. 
  crypt.CadesEnabled := True;

  crypt.HashAlgorithm := 'sha256';

  jsonSigningAttrs := TJsonObject.Create;
  jsonSigningAttrs.UpdateInt('contentType',1);
  jsonSigningAttrs.UpdateInt('signingTime',1);
  jsonSigningAttrs.UpdateInt('messageDigest',1);
  jsonSigningAttrs.UpdateInt('signingCertificateV2',1);
  crypt.SigningAttributes := jsonSigningAttrs.Emit();

  //  By default, all the certs in the chain of authentication are included in the signature.
  //  If desired, we can choose to only include the signing certificate:
  crypt.IncludeCertChain := False;

  //  Create the CAdES-BES attached signature, which contains the original data.
  crypt.Charset := 'utf-8';

  cadesP7s := crypt.OpaqueSignString('{ "abc": 123}');
  if (crypt.LastMethodSuccess = False) then
    begin
      WriteLn(crypt.LastErrorText);
      Exit;
    end;

  //  Verify the signature and extract the original JSON:
  originalJson := crypt.OpaqueVerifyString(cadesP7s);
  if (crypt.LastMethodSuccess = False) then
    begin
      WriteLn(crypt.LastErrorText);
      Exit;
    end;

  WriteLn('Original JSON: ' + originalJson);

  WriteLn('Success!');


  crypt.Free;
  cert.Free;
  jsonSigningAttrs.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.