How to Lock a PDF File? Top 8 Ways

PDF files are widely used to share documents, reports, and other information across different platforms. One important feature of a PDF file is the ability to restrict access. You can lock PDF file with a password to prevent anybody from opening the file, or you can limit certain actions like printing, editing, copying, etc. as per your choice.

In this guide, we will cover multiple methods to lock a PDF file. Whether it’s about locking a PDF file from editing, copying, printing, or unauthorized access, you can find the best methods here.

Table of Contents:

• Types of PDF Locking
• How to Lock PDF File Using Adobe
  • From Editing
  • From Copying
  • From Printing
• How to Lock PDF File Online
• How to Lock PDF File Using Software
  • With Document Open Password
  • With Restrictions – Editing, Copying, Printing
  • Lock Multiple PDF Files at Once
• Best Practices
• Conclusion

Types of PDF Locking:

There are two primary types of PDF locking:

1. Lock PDF with Document Open Password:

This is a type of PDF security where a password is required to open the PDF file. You cannot open and access the PDF file without knowing the correct password. This is a necessary step for the owner of the document to ensure that only authorized individuals can view the content.

2. Lock PDF with Document Restriction Password:

This type of security password is helpful in restricting certain actions on the PDF document. The types of PDF restrictions you can apply to your PDF files include:

• Copying: Stops users from copying text or images from the PDF.
• Printing: Restricts the ability to print the PDF document.
• Document Assembly: Prevents users from assembling multiple programs and documents into a single PDF file.
• Content Copying for Accessibility
• Page Extraction: Prevents users from extracting the content of a PDF document
• Commenting: Prevents users from adding, deleting, or modifying the comments in a PDF
• Filling of Form fields: Prevents users from filling form fields in a PDF document
• Signing: Prevents users from signing or approving the document
• Creation of Template Pages: Prevents users from creating new template pages in a PDF.
• Editing: Any changes that you make in a PDF file come under Editing. You can restrict all of such actions at once by locking a PDF file from editing.

How to Lock PDF File Using Adobe Acrobat Pro DC

Adobe Acrobat Pro DC offers comprehensive features for securing your PDF files. Here’s how to lock a PDF file using this software:

1. Open the PDF file in Adobe Acrobat Pro DC.
2. Go to the “Protect” tab in the top menu or in the Tools section.
3. Choose “Encrypt,” and then select “Encrypt with Password“.
4. Set the desired password and choose the restrictions you want to apply.
5. Save the document to apply the password and restrictions.

Now, we will go through the methods to lock a PDF file from editing, printing and copying using Adobe Acrobat Pro DC.

I. How to Lock PDF File from Editing

Lock PDF from editing using Adobe Acrobat DC:

1. Launch Adobe Acrobat Pro DC and open the PDF file you want to lock from editing.
2. Click on the “Protect” tab in the top menu.
3. From the dropdown menu, select “Encrypt“.
4. In the submenu, click on “Encrypt with Password“.
5. Check the box next to “Restrict editing and printing of the document. A password will be required to change these permissions“.

6. Enter a strong password in the “Password” field. Make sure to use a unique and complex password.
7. Ensure that “Changes Allowed” is set to “None” to disable editing in PDF file.

8. Click “OK” and confirm the password when prompted.

9. After setting the password and permissions, save the PDF file. The PDF file is now locked from editing. Anyone attempting to make changes will be prompted for the password.

Also Read: How to Edit a Locked PDF document?

II. How to Lock PDF File from Copying

Lock PDF from copying using Adobe Acrobat DC:

1. Launch Adobe Acrobat Pro DC and open the PDF file you want to lock from copying.
2. Click on the “Lock” icon on the left side.
3. From here, select “Permission details“.
4. In the Security method, choose the Password security option.

5. Check the box next to “Restrict…….” in the “Permissions” section (Copying comes under Changes Allowed, that’s why we choose this option here).

6. Enter a strong password in the “Password” field. Make sure to use a unique and complex password.
7. Ensure that “Changes Allowed” is set to “None” to disable copying in PDF file.
8. Click “OK” and confirm the password when prompted.
9. After setting the password and permissions, save the PDF file. The PDF file is now locked from editing. Anyone attempting to make changes will be prompted for the password.

Also Read: How to copy Content from protected PDF

III. How to Lock PDF File from Printing

Lock PDF from Printing using Adobe Acrobat DC:

1. Launch Adobe Acrobat Pro DC and open the PDF file you want to lock from printing.
2. Click on the “Protect” tab in the top menu.
3. From the dropdown menu, select “Encrypt“.
4. In the submenu, click on “Encrypt with Password“.
5. Check the box next to “Restrict editing and printing of the document. A password will be required to change these permissions”.
6. Enter a strong password in the “Password” field. Make sure to use a unique and complex password.
7. Ensure that “Printing Allowed” is set to “None” to disable printing in PDF file.

8. Click “OK” and confirm the password when prompted.

9. After setting the password and permissions, save the PDF file. The PDF file is now locked from printing.

Also Read: How to bypass PDF print restrictions?

How to Lock PDF File Online

You can also protect your PDF file using several online platforms. One such example is Smallpdf. Here’s how you can lock a PDF file online:

1. Go to the online website.
2. Choose the “Protect PDF” tool.
3. Upload your PDF file.
4. Set the password and restrictions as needed.
5. Click on “Encrypt PDF” to secure the file.
6. Download the locked PDF.

How to Lock PDF Files Using PDF Lock Software

This software allows you to password-protect your PDF files in a few easy steps. It uses the familiar options of Adobe Acrobat which makes it easy to use, and ensures that the Output file is compatible with Adobe and other PDF editors. The software is available for demo purposes to help you test the features. The demo version will lock PDF files but apply a watermark to them.

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You can use the software to lock PDF files with both document-open and permissions passwords. We have separated both scenarios into two sections for your convenience.

How to Lock PDF Files with Document-Open Password

1. Run the full version of the software on your Windows system.

2. Click on ‘Add File’ button to add one or more PDF files into the software.

3. Once the file(s) have been added, you can set the destination path to save the locked PDF.

4. Check mark the “Apply Document Open Password” option to lock the PDF files with a password.

5. Enter a password in the given boxes.
6. Now, apply the encryption method to encrypt the PDF file. RC4x128 is the standard encryption that all PDF applications support.

7. Click on the ‘Lock‘ button to start the process of locking the PDF file(s).

8. Congratulations, the process is complete. You can see the locked PDF files in the destination folder.

9. When you try to open the locked PDF file, you will get a prompt to enter the password.

Lock PDF Files from Copying, Editing & Printing Permissions

1. Run the full version software on your system.

2. Add the PDF files that you want to lock from copying, editing and printing using ‘Add Files’ button.

3. After that, change the destination folder where you want to save the locked PDF files.

4. In the next window, click on “Apply Document Restrictions” and choose the “Not allowed” option from the dropdown list of Printing. This will lock the PDF files from printing.

5. You can choose “Not Allowed” for Changes to protect the PDF content from editing and copying.

6. Finally, set a unique and strong password for the locked PDF files.

7. Next, set the encryption type to encrypt the PDF file. RC4x128 is the standard encryption that all PDF applications support.

8. Click on the ‘Lock’ button to lock the PDF files.

9. Once the PDF files are locked, you can view them in the destination folder.

Also Read: How to remove permissions from PDF file?

How to Lock Multiple PDF Files At One Time

Locking multiple PDF files simultaneously can save time. Adobe Acrobat Pro DC does not provide any method to do this. But, you can make use of PDF Lock software to process multiple files at once. Here is how the process goes:

1. Download, install and run the PDF Lock software on your PC.

2. Click on the Add Files button and select multiple PDF files that you want to lock.
3. You can also add a folder containing multiple PDF documents using the Add Folder button.

4. Once you have all the PDF documents added, go to the next window and apply whatever type of password you want to set.
5. Finally, click the Lock button to encrypt all the PDF files successfully.

Also Read: How to Unprotect Multiple PDF Files?

Best Practices for PDF Security

• Make sure that the password is unique and strong so that it is harder to guess.
• You can keep backup of your PDF files before locking them. It is always good to have a copy of the original PDF file just in case you forget the password.
• Do not share passwords through insecure applications to prevent unauthorized access to your PDF files.
• Latest versions of PDF editor applications provide better encryption methods, so keep them updated.
• You can choose between multiple encryptions methods in PDF lock software to lock PDF file.

Final Words

In order to safeguard sensitive information in a PDF file, you can lock it with a password. In fact, you can control how you lock PDF file. It can be a password-protected file that allows only authorized users to open the document or a locked PDF that prevents copying, printing, and editing. You can also lock multiple PDF files at one time using PDF Locker software. So, choose whether you want to use Adobe Acrobat Pro DC, an online tool or a third-party software to lock your PDF files.