Pascal (Lazarus/Delphi)

Remove All S/MIME Security Layers (UnwrapSecurity)

Demonstrates the Chilkat Mime.UnwrapSecurity method, which removes supported S/MIME security layers and restores the underlying MIME content. It takes no arguments and handles both layer orders: signed-then-encrypted and encrypted-then-signed.

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: A message can be both signed and encrypted, in either order, producing nested S/MIME wrappers. UnwrapSecurity peels them all off in one call — verifying signatures and decrypting as it goes — so you do not have to detect the layering and call Verify and Decrypt in the right sequence yourself. Decryption still requires the recipient's certificate and private key to be configured.

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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.Mime;

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

procedure RunDemo;
var
  success: Boolean;
  mime: TMime;

begin
  success := False;

  //  Demonstrates the Mime.UnwrapSecurity method, which removes supported S/MIME security layers and
  //  restores the underlying MIME content.  It takes no arguments and handles both layer orders
  //  (signed-then-encrypted and encrypted-then-signed).

  mime := TMime.Create;
  success := mime.LoadMimeFile('qa_data/secured.eml');
  if (success = False) then
    begin
      WriteLn(mime.LastErrorText);
      Exit;
    end;

  //  A single call peels off the signature and/or encryption layers.  (Decryption requires the
  //  appropriate certificate/private key to be configured first.)
  success := mime.UnwrapSecurity();
  if (success = False) then
    begin
      WriteLn(mime.LastErrorText);
      Exit;
    end;

  WriteLn('Security layers removed. Content-Type is now: ' + mime.ContentType);


  mime.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.