How to detect .doc password protection - php

Question

The following answer allows to detect password protected .docx files, after porting it to PHP: https://stackoverflow.com/a/14347730/1794894
$content = utf8_encode(file_get_contents($absolutePath));
if (mb_substr($content, 0, 2) == "ÐÏ") {
# DOC/XLS 2007+
$start = str_replace("\x00", " ", mb_substr($content, 0, 2000));
if (mb_strstr($start, 'E n c r y p t e d P a c k a g e') !== false) {
return true;
}
if ($extension == 'doc') {
return true;
}
}
How to also make a .doc specific check? Do .doc files also have a specific byte sequence? Or is it enough to only rely on the ÐÏ check at the first two characters of the file?
Or is the character at position 0x20B always equal to 0x13 in case of a password protected .doc?

Answer 1

Solved it based on the C# example from the post in the question.
We can not make use of a COM object, most servers do not run MS Word.
See Gist snippet: https://gist.github.com/rvanlaak/06ca1b65658a91240362

Answer 2

It should be something like this...
<?php
$word=new COM("word.application") or die("Cannot create Word object");
$word->Visible=false;
$word->WindowState=2;
$word->DisplayAlerts=false;
$doc = $word->Document->Open("/yourFile.doc");
$passwordProtect = $doc->Document->HasPassword;//true or false
$word->ActiveDocument->Close(false);
$word->Quit();
$word->Release();
$word=null;
?>
I can't test this code, hope it helps...