What a Word file or PDF reveals about you
A document says a good deal more than what is written on it. It is a well-known problem in law firms, newsrooms and government.
What a .docx carries
Word keeps a properties block that fills itself in:
- Who created it and who last modified it, using the account name.
- The company configured in that Office installation.
- Total editing time and the number of revisions.
- Creation and last-modified timestamps, down to the second.
What a PDF carries, and the usual mistake
A PDF stores metadata in two places: a properties dictionary and an XMP block in XML. Many tools clear only the first and call it done, leaving XMP with a second copy of the author, the software and the dates.
That is precisely the flaw the previous version of KillEXIF had, and one of the reasons for this rewrite.
And the timestamps of the archive itself
A .docx, .xlsx or .odt is really a compressed archive. Every part inside carries its own timestamp accurate to two seconds, which is enough to reconstruct when you were working even if the properties are clean. They also tend to carry your system username and the file permissions.