How to redact a PDF securely (and why a black box is not enough)
Bad redaction has leaked secrets from governments and companies. The classic mistake: drawing a black box over the text. The text is still underneath and anyone can recover it.
Why a black box is dangerous
A black rectangle is just a visual layer. The original text remains in the PDF content stream and can be extracted by copying it or with tools like pdftotext and "fake redaction" detectors.
Destructive redaction: the right way
Secure redaction removes the text bytes from the document, not just covers them. In Docuul, the redact tool deletes the text from the content stream and also draws the black box: hidden and unrecoverable.
- Open your PDF in the editor.
- Enable the Redact tool.
- Drag a rectangle over the sensitive information.
- Download the PDF: the text no longer exists in the file.
FAQ
Can redacted text be recovered?
No, with destructive redaction the text is removed from the file, not just covered.
Should I also clean metadata?
Yes, review the document metadata to avoid extra leaks.