private function compareHash( $hash1, $hash2 ) {
		$result = strlen( $hash1 ) ^ strlen( $hash2 );
		$len = min( strlen( $hash1 ), strlen( $hash2 ) ) - 1;
		for ( $i = 0; $i < $len; $i++ ) {
			$result |= ord( $hash1{$i} ) ^ ord( $hash2{$i} );
		}
		return $result == 0;
	}