Opdateret: 21. mar. 2020
The exposure of sensitive information in the Paul Manafort court case last year is a notorious example of how easy it is to bungle redacting PDF documents.
During the trial of Manafort, President Trump’s former campaign chairman, his lawyers filed a response to allegations that Manafort had lied to prosecutors. In the response, the lawyers attempted to redact a sensitive passage. But just by copying and pasting the redacted paragraph, it was possible to read the blacked-out parts. They revealed Manafort’s relationship with Konstantin Kilimnik, a former associate with ties to Russia.
Such simple errors are not unusual – slip-ups like these happen all the time.
Let’s take a look at the common ways to redact PDF documents and why they are problematic.
Common Practices Can Lead to Mistakes
There are numerous ways to redact or black out text. On macOS, for example, you can draw black boxes on top of PDFs using the Preview app.
You can also redact in Word. By changing the background color to black – but not removing the text – you can then save the document as a PDF.
Unfortunately, these ways of redacting PDF documents are not in themselves secure. If you are using the Preview app, for instance, you need to “flatten” the PDF document after adding the boxes. Flattening basically means integrating added elements into the PDF so they became part of it. If you haven’t flattened your PDF, the recipient can move the redacted boxes around. They can highlight, copy paste and reveal the redactions when the file is opened in Preview or other PDF readers. This is possibly what happened in the Manafort case.
The same applies to a Word document saved as a PDF. You can still select text in a PDF reader program and copy paste it to an editor, such as Notepad. This will allow you to see the previously blacked-out information.
Failing to adequately redact PDF documents in these ways can expose you and your business to potential harm and embarrassment.
How to Avoid Reverse Redactions in PDF Documents
So, how do you redact PDFs so that they can’t be undone? As already mentioned, one way is to flatten your redacted PDF. This is easily achieved by printing it, re-scanning it and saving it. Or you can take a screenshot and convert the image file back to PDF. Either of these ways will work.
Using permanent marker pens on the printed-out document and then scanning it will also work.
But a word of caution: Optical Character Recognition (OCR) tech is now sophisticated enough to work out the words that have been blacked out by hand.
Perhaps the best way to redact, then, is to edit the document in a word processor and replace the parts you want to redact with “[REDACTED]”. In that way the recipient can’t work out a short redaction by counting the number of characters.
What If You Have Vast Numbers of Redactions in Your PDFs?
These methods are sure fixes if your redactions are limited and you have plenty of available personnel.
If, however, your redactions are extensive, time-consuming and resource-intensive, you’re better off investing in a secure redaction tool. Note, there are important features you need to be aware of when searching for redaction software.
Are you looking for a redaction tool that can effectively and securely edit your PDFs? Sign up for a demo here.