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How to Secure a PDF Document Using PDFpen

Securing PDF documents is important. When you don’t secure your PDFs, you risk other people seeing, printing, modifying, sharing, and leaking your and your customers’ information.

You don’t need to work for a spy agency to care: No matter what your job or industry, a data breach is always bad.

So how do you secure your PDFs? PDFpen and PDFpenPro have two handy security features you can use: redaction and password protection.


Man reads redacted newspaper.
Redacted. Photo: Nada News by Pepe Medina. CC BY-NC-ND 2.0.

Redaction is the process by which PDFpen obscures and completely deletes text for security purposes.

If you want to share a document that contains classified info, it’s always prudent to redact it. 

Note that redacting is different from:

a) Placing a black rectangle over sensitive text.
b) Changing the background of the text to black.

The methods above simply hide the text as opposed to permanently removing it. That means that to see it, all someone needs to do is copy and paste the blacked-out text. Incredibly, this is what happened in a high-profile court case, as described in this VICE article.

True redaction – the type you can accomplish with PDFpen – replaces text with blank space or a black box. 

Using redaction

To redact text using PDFpen, follow these steps:

  1. Select the text you want to redact.
  2. In the menu, choose Format > Redact text.
  3. Choose Redact Text – Block if you want the text blacked out.
  4. Choose Redact Text – Erase if you want a blank space in place of the text.

Using “Redact All”

To remove sensitive information that repeats itself throughout a lengthy document, search for it and mark it for automatic redaction:

  1. Choose Edit > Find > Find and Redact.
  2. Type the text you want to redact.
  3. Choose a Redaction Style (Block/Erase).
  4. Click “Redact All.”

Password protection

Password-protected PDF.
Password-protected PDF. Photo by Wesley Fryer. CC BY-NC-ND 2.0.

Password-protecting your PDFs can prevent outsiders from opening or performing actions on your documents, depending on the type of password you set.

There are two types:

  • A user password encrypts the document so that only those with the password can view it.
  • An owner password allows viewing but permission settings can restrict modifying, copying saving, and/or printing. 

To summarize, when you set a user password, you restrict access. When you set an owner password, you manage permissions. A PDF can have the two types of passwords.

Secure a PDF document with a user password  

To set a user password, follow these steps:

  1. Choose File > Duplicate (Command+Shift+S). In the new document, choose File > Save (Command+S). Or use File > Save As (Command+Option+Shift+S).
  2. At the bottom of the Save dialog, select an Encryption option. We recommend Strong.
  3. Enter a password in the Password field.
  4. Re-enter the same password in the Verify field.
  5. Click Save.

Secure a PDF File with an owner password  (PDFpenPro)

To set an owner password, follow these steps:

  1. Open the Inspector window to and select the Document Permissions tab by clicking on the lock icon. 
  2. Click the Add button. A pop-up window will appear. 
  3. Enter a password in the Password field, and then re-enter it in the Verify field. Click OK to finish.
  4. Select your permissions. 
  5. Choose File > Save to apply these settings.

Note: The default encryption of document permissions is AES-128. To change this, add a user password. The permissions encryption will take on the same encryption level as the user password. 

To keep in mind when securing PDFs

Open door.
Open door. Photo by emdot. CC BY 2.0.

Password-protecting a PDF document doesn’t make it 100% secure.

With time and dedication, a hacker can crack PDF encryption. There are also PDF editing applications out there that actually don’t respect user permissions. That’s definitely not the case with trustworthy PDF editing applications such as Adobe Reader, Preview, and PDFpenPro.

Does that mean setting passwords is useless?

Not at all. As Michael E. Cohen says, “Just because someone can smash in a locked door is no reason to prop the door open.”

So do secure your PDFs. Download a free trial of PDFpen today to try our encryption feature.