How to prevent people from modifying your PDF files?

Learn how to secure your PDFs online by adding a password and encrypting them.

We are sending and sharing PDFs regularly, but have you ever considered how secure your PDF files really are? And did you know that you can password protect a PDF? This underutilized PDF feature is useful when you need to, for example, send an important email or sign a relevant form.

In just a few clicks, you can prevent others from editing data, or set file permissions to restrict activities, such as printing and copying.

Find out why it is a good idea to protect your documents, but also how to password protect a PDF file and disable it from being modified.

Why do you have to Protect PDF Files?

There has always been a need to protect sensitive data, and thus documents containing such data. In today's digital age, it is expected that we can protect our digital documents from unauthorized access and inappropriate use. For many people and especially for businesses, documents are a fundamental resource. They contain key information such as projects, plans, reports, contracts, and the like. Some documents represent intellectual property and require a higher level of protection and access to the document, as well as the disposal of its contents.

That is why it is important to password protect a PDF against unauthorized use, as well as against data leakage of sensitive documents or threats to the confidentiality and integrity of the data in the document.

Encryption is a good way to prevent an unauthorized person from viewing the contents of your confidential PDF file. Restricting access to a certain number of users is, however, just one of the approaches to document protection.

How does password protection work?

Password security

What protects a document is encryption. It ensures that only those you have shared the password with can get access to your file's content. Older versions of the PDF standard allow for encryption with 128-bit RC4, while with newer versions we use 128 and 256-bit AES encryption.

A strong encryption algorithm, combined with a strong password, will prevent unauthorized access to the file and your data will be protected. Simply create an open password and our PDF protection tool will do the rest.

Protecting certain elements of the document

If you would like to share the PDF file publicly, but you want to prevent the others from performing any unwanted actions on your document – it is also possible to protect certain elements of the document.

With our free online tool, you have the choice to protect the PDF document against:

  • Printing the content,
  • Copying the content,
  • Modifying the content.

There are two kinds of passwords that could be applied to a PDF file:

  • Open Password
  • Permission Password

An open password allows you to prevent unauthorized access to the file. By setting a password to your PDF file, unauthorized users will not be able to open or access your PDF.

Permission password can be used to limit the functionality of the PDF. It protects the PDF and at the same time prevents individuals from printing, copying, or modifying it. In other words, a user having an open password can get access to view the file, but will not be able to edit the file without having a permission password.

As an optional setting, you can select the „Rasterize“ option to prevent others from editing the document or revealing potential hidden areas, as all contents will be merged into one, non-searchable layer.


  • If you restrict usage rights and only specify a permission password, some programs might ignore these restrictions. We would recommend you choose an open password to encrypt and additionally secure your PDF.
  • Keep in mind that without the correct password you will not be able to open, edit, or remove the protection from your own PDF. Make sure you do not forget it!

How to Password Protect a PDF

Files shared, saved, or sent via the Internet are always at risk. The moment you consider the contents of a PDF confidential, the next step should always be to protect your document by adding a password and encrypting it. The available online tool such as PDF2Go's - Protect PDF, offer you the free solution to this problem! It will provide reliable password protection for your PDF files.

Easily create a password-protected PDF by following the next few steps:

  1. Go to our Protect PDF tool and upload your PDF file.
  2. Enter and repeat an open password.
  3. Choose what users of your PDF are not allowed to do (restrict actions to PDF by preventing printing, copying, or modifying of the document).
  4. Enter and repeat a permission password.
  5. Click on "Start".
  6. Download your new password-protected file!

How to remove password protection online?

If you do not have a program installed to remove passwords from PDF documents, PDF2Go’s – PDF Unlocker is an excellent online tool that you can use to easily remove password protection from a PDF file. We can only unlock your PDF if you already know the password.


  1. Go to and use our Unlock PDF tool.
  2. Upload your protected PDF and enter the password it is protected with.
  3. All you need to do next is to click on “Set Password”. This will remove the password from your PDF.

Will I be able to edit the PDF again?

After successfully unlocking and removing your PDF password, you will be able to edit content or extract images from the unprotected PDF file without any restriction. To do this, you would just have to convert the PDF file into one of the editable formats (Word, Excel, PowerPoint). After making your edits, by using our PDF converter, you can convert it back to PDF again.