MIME S/MIME Signing Algorithm Properties

See more MIME Examples

Demonstrates the properties that control S/MIME signing: SigningAlg (the RSA signature scheme, PKCS1-V1_5 or RSASSA-PSS), SigningHashAlg (the message-digest algorithm), Micalg and Protocol (the micalg and protocol parameters of a multipart/signed Content-Type), and UseXPkcs7 (whether historical x-pkcs7 media-type names are used). The properties are configured before creating a detached signature.

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;

begin
  success := False;

  mime := TMime.Create;
  success := mime.SetBodyFromPlainText('This message will be signed.');
  if (success = False) then
    begin
      WriteLn(mime.LastErrorText);
      Exit;
    end;

  //  SigningAlg is the RSA signature scheme.  The default is PKCS1-V1_5; set RSASSA-PSS (or pss) for
  //  RSASSA-PSS.
  mime.SigningAlg := 'PKCS1-V1_5';

  //  SigningHashAlg is the message-digest algorithm.  The default is sha256.
  mime.SigningHashAlg := 'sha256';

  //  Micalg and Protocol are the micalg and protocol parameters written into a multipart/signed
  //  Content-Type header field.  They are normally set automatically, but can be controlled here.
  mime.Micalg := 'sha-256';
  mime.Protocol := 'application/pkcs7-signature';

  //  UseXPkcs7 controls whether newly created S/MIME media types use the historical x-pkcs7 names.
  mime.UseXPkcs7 := False;

  //  Load a signing certificate (with private key access) from a PFX.  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;

  //  Create the detached signature using the algorithms configured above.
  success := mime.AddDetachedSignature(cert);
  if (success = False) then
    begin
      WriteLn(mime.LastErrorText);
      Exit;
    end;

  WriteLn('Signed with SigningAlg=' + mime.SigningAlg + ' SigningHashAlg=' + mime.SigningHashAlg);


  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.