Check .doc and .docx for active file encryption

function.php

/**
* Check or the file is password protected based on the top file contents.
*
* @param string $absolutePath
* @return bool
*/
public function checkFileEncryption($absolutePath)
{
    $content = utf8_encode(file_get_contents($absolutePath));
    if (mb_substr($content, 0, 2) == "ÐÏ") {
    
        // DOCX/XLSX 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;
        }
        
        // DOC 2005-
        if (mb_substr($content, 0x20B, 1) == "\x13") {
            return true;
        }
    }
    return false;
}