How to sign password-protected PDFs

Nowadays, you can use an electronic signature, or eSignature, to sign your important documents, including secured PDFs. 

Secure PDF files are protected by a password, encryption, or both.

The easiest way to sign them is to enter the password or decryption key and use your choice of software to add your signature. 

For some documents, you may need extra permission to edit PDFs. In this case, you either need to get the permission details from the document’s owner or remove the password. 

Let’s look closer at how to add digital signatures to PDF documents on a range of devices.

What is a secured PDF?

A secured PDF is a password-protected or encrypted PDF.

Their security settings restrict who can access and change them, making them ideal for legal and commercial contracts. 

Locked PDF files use:

  • A password. There are two types of passwords you can use to protect a PDF: open or permissions. “Open” passwords only let you view the secure PDF, while “permissions” passwords let you change the settings and edit the PDF.
  • Encryption: You can also encrypt a PDF with an algorithm and use a decryption key to unlock it. 

We’re going to focus on how to digitally sign password-protected PDFs.

How to sign a secured PDF without a password on Windows

First, let’s explain how to add a signature to PDF documents in Windows without a password.

There are three methods.

1. Using Google Chrome

To sign your secure PDF in Google Chrome, take the following steps:

  1. Open File Explorer and right-click your password-protected PDF. Click Open with and choose Google Chrome. Your PDF will open as a web page.
  2. Press Ctrl + P on your keyboard to open the Print dialog box.
  3. From the Destination menu, choose Save as PDF. Choose a file name and location, and click Save to save an unlocked version of your PDF.
  4. Add your signature to the document using your favorite document-signing solution.

2. Using Google Drive

You can sign locked PDF files in Google Drive using the following method:

  1. Upload your secure PDF to your Google Drive account.
  2. Right-click your PDF document and click Open with > Google Docs.
  3. Next, click Share and export>Save as and choose PDF document (.pdf)
  4. Click OK to resave the file without password security. You can now sign the document using your choice of software.

3. Unlocking PDFs online

Another way to unlock PDFs is to use an online tool.

There are many free tools to choose from, so make sure you check the reviews before settling on a solution. 

Once you’ve chosen a tool, you can upload your protected PDF document and follow the instructions to remove the password.

You can then resave the PDF and add your signature. 

How to sign a secured PDF document on Mac

Now, how to electronically sign a secured PDF on Mac. There are two main methods:

1. Using Preview

To sign your secure files in Preview, take the following steps:

  1. Right-click your secure PDF and click Open with > Preview.
  2. Enter the PDF’s password, then press Enter to open the file.
  3. Click File > Save and uncheck the Encrypt option in the Save dialog box. 
  4. Click Save, and then add your signature using Preview or your favorite software.

2. Using Safari

You can also unlock your file in Safari on macOS by doing the following.

  1. Open Safari and press Command + O on your keyboard.
  2. Select your secure PDF and click Open.
  3. Enter the password to unlock the PDF.
  4. Next, press Command + P to open the Print dialog box. Click the PDF drop-down menu and choose Save as PDF.
  5. Choose a location and file name, then click Save. You can now eSign the PDF.

How to sign a secured PDF on Android

If you want to sign your secure PDF on your Android device, follow these steps:

  1. Open your Files app and go to Documents.
  2. Find the PDF you want to open and long-tap it to bring up the list of options for that file. 
  3. Tap More > Open with and choose Drive PDF Viewer.
  4. Enter the password for your PDF document and tap Open.
  5. Tap the Save to Drive symbol (the Google Drive logo with “+” on it). 
  6. Enter your desired document name, then tap Save. Now, sign your PDF. 

How to sign a secured PDF on iOS

If you have an iOS device, you can sign your file using the following steps:

  1. Open the Files app and tap on your secured PDF.
  2. Enter the PDF’s password, then tap Go.
  3. Tap the three-dot menu in the top-right corner of your screen. Select Change Password, then tap Remove Password.
  4. Sign the PDF.

How to sign a secured PDF in Adobe Acrobat Reader

The final method we’re going to look at is how to digitally sign a secured PDF in the Adobe PDF reader: 

  1. Right-click your PDF form. Click Open with, then choose Adobe Acrobat Pro or Adobe Acrobat Reader DC (whichever you use).
  2. Click Tools > Protect > Encrypt and choose Remove Security.
  3. Save the document, then open it again and click the sign button in the toolbar. You can also click Tools > Fill & Sign.
  4. Choose Add Signature and create your electronic signature
  5. Select Apply and click the area you want to add your signature. Then, save your signed document.

Signing PDFs is as simple as it gets

You should now know what a secured PDF document is, and how to unlock one.

It’s then a simple matter of using your preferred document solution to add your signature.

However, as we mentioned, this can render the signature invalid in some contexts.

You’re much better using a solution like PandaDoc, which offers a range of tools to access, sign, and share documents.

We’re ESIGN and UETA compliant, and provide an electronic certificate with every signed document.

Plus, unlike the above options, our electronic audit trail means you know exactly who signed what, and when.

Start a free 14-day trial with PandaDoc today and learn how easy signing secure PDFs can be!