True Redaction vs. Black Box Overlay: Why Your PDFs Might Not Be Secure

2025-11-30•True Redact Team

You've carefully drawn black boxes over sensitive information in your PDF. It looks redacted. But is the data actually gone? In many cases, the answer is a shocking no.

The Black Box Illusion

Many common PDF tools—including some versions of Adobe Acrobat—offer annotation features that appear to redact content but actually just overlay it. The original text remains in the file and can be extracted by:

  • Copying and pasting the "redacted" area
  • Opening the PDF in a text editor
  • Using PDF extraction tools
  • Examining the PDF's internal structure

Real-World Failures

This isn't a theoretical risk. High-profile redaction failures include:

  • The Manafort Case (2019): Lawyers accidentally revealed sensitive information by using improper redaction in court filings
  • TSA Security Manual (2009): A government document with "redacted" screening procedures was fully recoverable
  • Countless FOIA Releases: Improperly redacted government documents regularly expose confidential information

What True Redaction Looks Like

Proper redaction permanently removes data from the document. This means:

  • The underlying text is deleted, not just covered
  • Metadata is cleaned or removed
  • Hidden layers and embedded content are addressed
  • The PDF is flattened to prevent layer manipulation

How to Test Your Redaction

Before sharing any redacted document, verify the redaction is permanent:

  1. Copy test: Try to select and copy text from the redacted area
  2. Search test: Use Ctrl+F to search for terms you redacted
  3. Text extraction: Use a PDF-to-text converter and check the output
  4. Metadata check: Examine document properties for hidden information

The True Redact Approach

True Redact performs permanent, forensic-grade redaction:

  • Text is completely removed from the document structure
  • PDFs are flattened to eliminate hidden layers
  • OCR text layers are regenerated without sensitive content
  • Metadata is cleaned automatically

When you redact with True Redact, the data is gone—permanently and irreversibly.