encrypt pdf

How to Encrypt a PDF

by Hung Nguyen

You can also read this article in Portuguese, Spanish and Vietnamese.

Password protect PDF files with ... the Smallpdf Protect tool. Not all heroes wear capes!

PDF files are great to use, as they cannot be edited. However, you may not even want others to view the content of your files at times. For such cases, you can lock your PDF files entirely with a password.

Standard PDF password lockers are usually unreliable, and the unencrypted passwords can be easily removed with an online password remover software (admittedly, we have one ourselves).

weak password

What an unencrypted password looks like.

To prevent such cases, you can rely on our Protect PDF tool. We lock your PDF files with robust 128-bit AES encryption. With this, it's almost impossible to open the files without the correct password. The tool itself is pretty much self-explanatory, but here are the instructions on how to encrypt a PDF anyway.

How to encrypt a PDF with Smallpdf:

  • Upload your PDF to encrypt it via the Protect PDF tool.

  • Enter your password - and DON'T forget it!

  • Click 'Encrypt PDF' and let the encryption begins.

  • Download your locked PDF.

encrypt pdf file with smallpdf

128-bit AES encryption for the strongest of all passwords!

Is the process secure?


All files and passwords that are transferred via our online platform are done through secure SSL connections. Furthermore, all files that are uploaded and processed will be deleted after an hour. The passwords that you type into the tool to encrypt your files are also never saved either.

As Smallpdf operates online, you can access our platform via your favorite internet browser (Firefox, Edge, Safari, Chrome, etc.). Similarly, it doesn't matter if you are on a Windows, Linux or Mac, you can always access Smallpdf. Our site is online, all year long!

Can Smallpdf unlock these files?


Not at all. The files are so strongly encrypted that you need to know the exact password to unlock them. Because of this, make sure to write these passwords down. Or better yet, just set a unique password that only you can remember!

How to encrypt a PDF can't get any simpler with the aid of Smallpdf. Our tools are free to use, twice an hour. As such, there's no excuse not to lock your files when they need to. In case you wish to password protect files in other formats, you can always convert them to PDF format to use our tool for the encryption.

Aside from how to encrypt a PDF file, do you have any other questions on how to securely handle your PDF files? Our team is always available to help via our Helpdesk.

Hung Nguyen
Hung Nguyen
Content Marketing Manager