PHP Excel Password not working

I want to secure my xlsx file .
I exported my xlsx file using PHPExcel . which is been downloaded successfully. 

but i want to open this file as secured. set to open

Code:

$objPHPExcel->getSecurity()->setLockWindows(true);
$objPHPExcel->getSecurity()->setLockStructure(true);

$objPHPExcel->getSecurity()->setWorkbookPassword('secret');

Code:

$objPHPExcel->getActiveSheet()->getProtection()->setSheet(true);
$objPHPExcel->getActiveSheet()->getProtection()->setSort(true);
$objPHPExcel->getActiveSheet()->getProtection()->setInsertRows(true);
$objPHPExcel->getActiveSheet()->getProtection()->setFormatCells(true);

$objPHPExcel->getActiveSheet()->getProtection()->setPassword('password');

both are not working. I do know why. Kindly help me to solve the problem