use CGI;
 my $q = new CGI;
 my $Key= $ENV{PATH_INFO};

  unless ( substr($Key,0,1) eq 'Z' ) {
      print $q->header,
            $q->start_form(-action => $ENV{SCRIPT_NAME}."/H" . $ENV{QUERY_STRING}),
            " ... autenticate form ...";
      print $q->redirect();
  }
  print $q->header;
  print " ... autenticated data ... ";