Protecting Privacy: How to Properly Redact PDF Documents

Classified documents will eventually see the light of day, but it will take some time before they do. In most cases, it can take at least 10 years, but in others, it can take up to 25.

Until a document gets the classification, you may be able to share it if you redact it. Redaction refers to those black lines hiding certain sections of text that include sensitive information. If you share via digital document, then you need to know how to redact a PDF.

PDFs are a great way to share documents. So, let’s look at some key tips if you need to redact a PDF without Adobe.

How to Redact a PDF

First, you’re going to need some sort of PDF editing software, such as pdfpig. Make sure this is a tool that doesn’t collect any personal user data. You should probably avoid trying to redact a PDF online. 

Make sure the software you choose comes with a redact tool. This will be different from just a highlighter or black marker brush. It should allow you to easily hide sections of text just by clicking and dragging.

Ensure 100% Opacity

Opacity refers to how transparent a color is. 100% capacity means there is no transparency, and therefore you can’t see through the color. Redaction should always be done with 100% opacity.

Even if the opacity is set at 99%, someone can easily see through it. All it takes is some light-level editing in Photoshop and they can read the text as plainly as day.

Cover the Text Entirely

It’s key to cover all of the text completely. Nothing should stick out, not even the bottom of a Q or the dot of an I. Leaving anything to the imagination could compromise the sensitive info in a document.

There have been many, many cases where someone tries to black out text in a PDF, but they leave part of the letters exposed. Anyone can then do some simple forensic analysis to determine what the hidden line says.

Disallow Edits

Some PDF tools save multiple versions of a document. That way, you can recover an older version if you make a mistake. The last thing you want to do is share this document with its previous, unredacted versions.

Make sure to disable any versioning and send only non-versioned documents. Just to be safe, export the document from the PDF editor. This should usually save a single document with no compromising metadata.

Use Secure Data Removal

It’s not safe to simply delete a sensitive document and go about your day. Your recycling bin or trashcan is an unencrypted folder that anyone can access. Even deleted items are easy to recover with the right software.

Instead, you need secure data deletion. This usually comes in the form of a shredding tool, such as Bleachbit, which securely erases it. Via some computer wizardry, it becomes next to impossible for a bad actor to find it in your hard drive’s unused data sections.

Redact Your PDFs Today

Now you know how to redact a PDF, and do so with the ultimate privacy in mind. Make sure to use 100% opaque and full-coverage redaction tools. Avoid sharing previous versions and securely delete any documents that require it.

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