Before a PDF leaves the building: the hidden-data check
4 min read
Files reviewed only for their visible content sometimes cause trouble through what isn't visible. The check takes one minute.
What a PDF quietly records
Beyond the page content, a PDF has a document info area: author, title, producing software, creation and modification timestamps, filled in automatically. A PDF exported from Word commonly carries the author's account name — often a full real name or a corporate ID.
Usually harmless — until the document is supposed to be anonymous: sealed bids, review materials, whistleblowing documents. Document info is visible in the PDF Info tool or your viewer's document properties.
Covered is not deleted
Drawing a black rectangle over sensitive text is not redaction. The text underneath is fully intact, and selecting and copying the covered area reveals it verbatim. Incidents caused by exactly this have made the news repeatedly, involving both companies and government bodies.
The test is trivial: drag-select over the covered area. If text gets selected, it is not gone. Real fixes: delete the content in the source document and re-export, or convert the page to an image so no text data survives.
Stray pages from file reuse
Reused files produce their own incidents: a cover page addressed to the previous recipient, or internal review notes still attached at the end. One pass through the page thumbnails before sending catches these.
Found one? The delete-pages tool removes it in seconds.
The one-minute outbound checklist
For any document leaving your organization, check these four.
- Document info (author/title) contains no name that shouldn't be exposed
- Text under any blacked-out area genuinely cannot be selected
- No page in the file is meant for a different recipient
- The filename itself leaks nothing (internal project codenames, etc.)