$objPHPExcel = PHPExcel_IOFactory::load($inputFileName);
which will try to identify the filetype automatically, and load the file using the appropriate loader in a single step
$inputFileType = PHPExcel_IOFactory::identify($inputFileName);
$objReader = PHPExcel_IOFactory::createReader($inputFileType);
$objPHPExcel = $objReader->load($inputFileName);
which identifies the reader to use for a the file, instantiates a reader of the identified type, then loads the file
re: "Cannot read encrypted file"
It's pretty self-explanatory: PHPExcel cannot read Excel files that are encrypted.