17         $sString = 
"ox{$sString}id";
 
   19         $sKey = $this->
_formKey($sKey, $sString);
 
   21         $sString = $sString ^ $sKey;
 
   22         $sString = base64_encode ( $sString );
 
   23         $sString = str_replace( 
"=", 
"!", $sString );
 
   38         $iKeyLength = (strlen( $sString ) / strlen( $sKey )) + 5;
 
   40         return str_repeat( $sKey, $iKeyLength );