public function configure( $useDigits, $useSmalls, $useLarges, $useSigns, $strength ){
		if( !( $useDigits || $useSmalls || $useLarges || $useSigns ) )
			throw InvalidArgumentException( 'Atleast one type of characters must be enabled' );
		$this->useDigits	= $useDigits;
		$this->useSmalls	= $useSmalls;
		$this->useLarges	= $useLarges;
		$this->useSigns		= $useSigns;
		$this->strength		= $strength;
	}