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Redaction Checker

A PDF redaction is only secure if the text under the black box is actually deleted. Drawing a box over text, or marking a redaction without applying it, leaves the words in the file, where anyone can copy, search, or extract them.

PDF
Drop a redacted PDF here or click to browse
or paste from clipboard (Ctrl+V) · PDF
Files stay in your browser. Nothing is uploaded.

How to check if a PDF redaction is secure

  1. Add the redacted PDF

    Drop the PDF on the tool, click to browse, or paste it from your clipboard. The check starts on its own.

  2. Read the verdict

    The tool reports how many leaks it found, grouped by page with a small preview that outlines each one, plus a File group for properties and old versions.

  3. Review what leaked

    Each leak shows what kind it is and the exact text anyone could recover, such as a name under a black box or the author email in the properties.

  4. Download a safe copy

    Click Download safe copy to save a new PDF where leaking pages are flattened to images with the hidden areas painted over, and every hidden extra is gone.

Why use this tool

Finds text under boxes

Every page is drawn and each line of text is compared with what is actually visible, so words covered by a black box or written in white on white are caught and read back to you.

Catches unapplied redactions

Areas marked for redaction but never applied still hold the original text. The tool lists them along with the words underneath.

Checks the hidden extras

Comments, document properties such as the author, attached files, hidden layers, text parked outside the page, and earlier saved versions are all reported.

Recovers removed text from old versions

When a file was saved on top of an earlier version, the tool opens that earlier version and lists lines that no longer appear in the current one.

One-click safe copy

Pages with leaks become images with the leak areas painted over; clean pages are copied as they are. The new file has no properties, attachments, layers, or history.

Nothing leaves your browser

The PDF is read, checked, and rebuilt on your device. It is never uploaded, which matters when the whole point is that it is confidential.

About this tool

Most failed redactions look perfect on screen. Someone draws a black rectangle over a name, prints to PDF, and sends it. The rectangle hides the words from the eye, but the text is still in the file underneath it, so selecting, copying, searching, or extracting the page brings it straight back. The same goes for redactions that were marked but never applied, white text on a white page, comments left in the margin, and the author name stored in the document properties.

This tool runs the checks a careful recipient would. It draws every page and compares each piece of text with the pixels where that text should appear. If the area is one flat colour, the text exists but cannot be seen, and the tool reports it with the recovered words. It also lists unapplied redaction marks, comments, text placed outside the page, attached files, hidden layers, and document properties, and it counts earlier saved versions inside the file. When an earlier version holds lines the current one dropped, those lines are shown too.

If anything is found, Download safe copy builds a new PDF. Pages with leaks are rendered to images at twice the normal resolution with every leak area painted over, so nothing underneath survives; pages without leaks are copied with their text intact. The copy carries no properties, no metadata block, no attachments, no layers, and no earlier versions. To strip only the properties and keep the text selectable, use remove PDF metadata. To see every word a PDF still contains, try PDF to text, and for photos, the EXIF remover clears location and camera data.

Frequently asked questions

How does the redaction checker work?
It draws each page and samples the pixels where every piece of text sits. Visible text always puts ink in that area. If the area is one flat colour instead, the text is in the file but hidden, under a box or in invisible ink. It also reads annotations, document properties, attachments, layers, and the file structure for earlier versions.
Is my PDF uploaded anywhere?
No. The file is read, checked, and rebuilt entirely in your browser. Nothing is sent to a server, so a confidential document never leaves your device.
What kinds of PDF does it accept?
Any standard PDF, one file at a time. A PDF that needs a password to open cannot be read. Scanned PDFs with no text layer are accepted; there is simply no hidden text to find, and the tool says so.
What does the safe copy change?
Pages with leaks become images with the leak areas painted over, so their text can no longer be selected or searched. Pages with form fields are rendered the same way. Other pages keep their selectable text. The new file drops document properties, the metadata block, attachments, layers, comments, and every earlier version.
Are there limits?
Long PDFs work, but every page is drawn, so a document of several hundred pages can take a minute. Text inside images is not read, and hidden text is judged from how the page looks, so a word under a solid box is caught while a word under a photo or a pattern may not be.
Why does it list the author or the program that made the file?
Document properties travel with the file and often name the person, company, or software behind it. They are not visible on the page, which is exactly why they leak. The safe copy removes them, or you can clear them alone with the metadata remover.

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