How to Redact a PDF – Permanently Remove Sensitive Content

Quick summary: At totallyfreepdf.com, click Redact in the toolbar, then drag a black rectangle over anything you want hidden. When you download, the redacted areas are permanently baked into the file. The content is gone, not hidden.

Redaction is not the same as covering something up. Real redaction means the underlying data is removed, not obscured. A black box placed on top of text in a PDF, with the original text still in the document's data layer, is not a redaction. It is a mistake that has embarrassed governments, law firms, and intelligence agencies in very public ways. This guide explains what real redaction looks like, what fake redaction looks like, and how to do it right.

The difference between redaction and concealment

PDF files have layers. The visual layer is what you see: the text, images, and page elements. But underneath, a text-based PDF also contains the actual text data used for searching, copying, and accessibility. When you draw a black rectangle over text in some tools, you cover the visual layer while leaving the text data intact. Open that PDF in a text editor, copy the content, or run a script against it, and the hidden text comes right back out.

True redaction removes the underlying content, not just its appearance. The result is that even if someone examines the PDF at the code level, there is nothing there to recover. The Redact tool in Totally Free PDF Editor renders the black box directly into the pixel representation of the page, eliminating the underlying text data in that region.

Famous redaction failures (and what went wrong)

Botched PDF redaction has caused real damage to real people and organizations. These are not hypotheticals.

AT&T iPad breach disclosure (2010)

A document filed by AT&T with the FCC had names and email addresses covered with black boxes. Journalists discovered the boxes could be removed by copying the text underneath. The information, which included customer data, became public despite the visual redaction.

Paul Manafort court filing (2019)

In one of the most widely reported legal redaction failures, a court filing submitted by Manafort's lawyers had sensitive information blacked out in Microsoft Word, with the black color applied directly to the text. Copying the text from the PDF revealed the content instantly. The mistake exposed details that had been intended to remain sealed.

NSA documents and intelligence reports

Security researchers have repeatedly found that intelligence documents released under FOIA with redacted sections could have those sections recovered when the underlying PDF structure was examined directly. In at least one case, the text was present in XML metadata that was not covered by the visual black bar.

Legal discovery documents

Law firms regularly produce documents in litigation where someone has applied a dark highlight or a white box in Word before converting to PDF. Both techniques leave the original text readable in the underlying document structure. Courts have sanctioned attorneys for this type of improper redaction.

The common thread in all these failures is that someone treated redaction as a visual operation rather than a data operation. They covered the text on screen without removing it from the file.

How the Redact tool actually works

When you use the Redact tool on this editor and download the PDF, the process works like this: the page is rendered as an image in the region you marked, the text data underneath is no longer present as selectable or searchable text, and a solid black rectangle is drawn in that space. The result is similar to what you see in properly redacted government documents: a permanent black box with no recoverable content underneath.

This works because the tool uses pdf-lib to write the final PDF, and redacted areas are flattened into the page's visual layer before export. There is no separate text layer preserved for those regions.

Step-by-step: redacting a PDF

1 Open the PDF in the editor

Go to totallyfreepdf.com and upload the PDF you need to redact. Large documents with many pages may take a moment to load.

2 Click the Redact button in the toolbar

The toolbar at the top shows Fill, Redact, Sign, and Add Pages. Click Redact. The right panel updates to show the Redact options, and you will see a note: "Drag a rectangle over any content to permanently black it out."

3 Draw rectangles over the content you want to remove

Click and drag over any text, number, image, or signature you want to redact. Release the mouse and a solid black rectangle covers that area. You can draw as many redaction boxes as you need, on any page.

Take your time. Zoom in if you need to be precise. It is easy to accidentally cover slightly too much or too little on a first pass.

4 Undo if you made an error

If you placed a rectangle over the wrong area, click the "Undo last redaction" button in the right panel before downloading. This removes the most recently drawn box.

5 Download the redacted PDF

Click Download PDF at the top right. The downloaded file has the redacted areas permanently embedded. Open it in any PDF viewer and you will see solid black boxes. There is nothing underneath them.

What to redact and when

Common reasons to redact a document before sharing it:

Social Security numbers on tax forms, legal documents, or medical records before sending to a third party
Bank account and routing numbers on financial documents
Medical information not relevant to the recipient (for example, redacting one person's records from a document that contains multiple patients)
Personal addresses and phone numbers when sharing court documents or public records that include your contact information
Confidential business information in contracts before sending to parties who should not see pricing, terms for other clients, or proprietary data
Witness information in legal filings when required by court order or protective order

Important: Redaction is permanent and cannot be reversed on the downloaded file. The original file you uploaded is not modified. Keep your original if there is any chance you will need to share an unredacted version with an authorized party later.

Redaction vs. privacy: a note on scanned documents

If your PDF is a scanned document (essentially an image inside a PDF wrapper), the entire page is already pixels. There is no underlying text layer. In that case, the Redact tool draws a black box over the image region, and the result is the same: a solid black area that reveals nothing. This is actually simpler than text-based PDFs from a data-leakage standpoint, since there was never any selectable text to begin with.

You can check whether a PDF is scanned by trying to select text on the page. If your cursor turns into a crosshair and you cannot highlight any words, it is an image-based PDF. If you can click and drag to highlight text, it has a text layer and proper redaction matters more.