Pascal (Lazarus/Delphi)

Add a Detached Signature (Header Placement Control)

Demonstrates the Chilkat Mime.AddDetachedSignature2 method, which creates the same multipart/signed structure as AddDetachedSignature, with a second argument controlling whether the existing message header fields are transferred to the new outer entity.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: Signing wraps the content in a new outer multipart/signed, which raises the question of where the message-level headers (Subject, From, To) should live. This variant lets you choose: transfer them up to the outer entity so the signed message looks like a normal email, or leave them on the inner part. Transferring is typical for email; the finer control matters when the signed entity is embedded in a larger structure.

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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.Mime;

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

procedure RunDemo;
var
  success: Boolean;
  mime: TMime;
  pfxPassword: string;
  cert: TCert;
  transferHeaderFields: Boolean;

begin
  success := False;

  mime := TMime.Create;
  success := mime.SetBodyFromPlainText('This message will be signed.');
  if (success = False) then
    begin
      WriteLn(mime.LastErrorText);
      Exit;
    end;
  //  Load the signing certificate (which must have access to its private key) from a PFX file.
  //  The PFX password should come from a secure source rather than being hard-coded.
  pfxPassword := 'myPfxPassword';
  cert := TCert.Create;
  success := cert.LoadPfxFile('qa_data/signer.pfx',pfxPassword);
  if (success = False) then
    begin
      WriteLn(cert.LastErrorText);
      Exit;
    end;

  //  AddDetachedSignature2 is the same as AddDetachedSignature, but the 2nd argument controls whether
  //  the existing message header fields are transferred to the new outer multipart/signed entity.
  transferHeaderFields := True;
  success := mime.AddDetachedSignature2(cert,transferHeaderFields);
  if (success = False) then
    begin
      WriteLn(mime.LastErrorText);
      Exit;
    end;

  success := mime.SaveMime('qa_output/signed.eml');
  if (success = False) then
    begin
      WriteLn(mime.LastErrorText);
      Exit;
    end;
  WriteLn('Detached signature added (headers transferred).');


  mime.Free;
  cert.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.