How to Unlock a Secure PDF?

How to unlock a secured pdf

In this guide, I will show you how to unlock a secure pdf. Keep reading!

File encryption is more common nowadays. Almost all companies are used to using PDF to store business data and even encrypt their files to assure security from any type of unauthorized access. There are three types of encryption, 40, 128, and 256 bits. The safest encryption is 256 bit and it is also the hardest to crack.

 So, this article will give detailed information about how to unlock a secure pdf file so that you can use the file after removing the password.

What is a password protected PDF?

PDF is the short form of Portable Document Format. It is a world-wide used format created by Adobe. This format has very fascinating features such as it is not easy to edit directly, and its characters will not be garbled; no matter where the user opens the file.

That’s why businesses, schools, etc. are very fond of using this format to store and send their data from one system to another. Therefore, those PDF files are made password protected. The owner of the PDF file can enable the password to secure the PDF.

In a password protected PDF the password can be of two types; owner password and the user password.

Owner Password

To prevent people from copying, editing, and printing a PDF, the password is required. However, sometimes no password is required to view the PDF file, but you’ll find all those functions are locked out if the owner has selected to protect the document. That is called an owner password. It depends upon the owner for locking the functions while creating the password.

If you want to edit, copy, or print the password-protected PDF file then you need to know the owner password.

User Password

PDFs are useful for various reasons, but the PDFs with password protection are even more useful so that only those can view or go through the file having the password with them. The password required to view a PDF file is called the user password.

It is very essential to know the user password to unlock a PDF that is secured. By having this password you can access the file but can’t be edited because the user password can’t have the edit rights like owner password.

How can I remove the password from a password-protected PDF?

There are various ways of removing a password to unlock PDF files, but in this article, we will discuss the three most straightforward methods that can be easily performed by any user.

Using PDF password Refixer

To unlock a secure PDF file, you need to carry out the following steps exactly the way it will be mentioned.

Step 1. First and foremost you have to download a PDF password remover software named PDF password RefixerIsumsoft password Refixer is one of the most useful software and hence helps you to unlock PDF files.

Guide to Unlock a Secured PDF using PDF password RefixerStep 2. After downloading and installing, you will have to open the software. It has an interface as mentioned here:

Guide to Unlock a Secured PDF using PDF password Refixer

Step 3. Click on the ‘Open’ menu and select the desired PDF file which is password protected (Refer to the picture).

Guide to Unlock a Secured PDF using PDF password Refixer

Step 4. After selecting the desired file, you will have to choose the path of the document and add the path to the software. (As the path highlighted in the next pic).

Guide to Unlock a Secured PDF using PDF password Refixer

Step 5. Then after confirming the path, you will have to select the password attack type and also select the relevant option such as proper Range and Length of the password. (Refer to next pic to get an idea of attack type and for selection of appropriate length and range).

Guide to Unlock a Secured PDF using PDF password Refixer

Note: This software can initiate four types of attacks on the password to obtain the actual password. So the four types of attacks are discussed below:


Brute Force is the most straightforward attacking process to extract the password of the encrypted PDF file. By this process, the software tries to retrieve the password by working on every character combination one by one. This type takes a lot of time if a long password is applied.

For example, for a one-letter password, it checks all the 26 characters, and for two letters it calculates 26*26=676 combinations.


Mask attack is a useful attacking process if you remember a part of the password. This attack is slightly better than brute attack as it takes less time to track down the password.

For example, if you know the last two letters of a password then you can use this instead of Brute force as the latter would take much more time than Mask attack.


Through the dictionary attack, the software matches the entire expected password with the words in the dictionary. So the chances of password extraction are very high as most of the people choose words from the dictionary.


It is the most advanced and almost similar to brute force but it takes much less time to extract the original password as it does not consider meaningless combinations.

So through these four attack types, PDF password Refixer software initiates the PDF password removal technique and eventually generates the original password.

Step 1. After selecting the desired length and range click on “Start” to allow this PDF password remover to work on the file and eventually this software will display the actual password. (Refer to these pictures where the real password is revealed).

Guide to Unlock a Secured PDF using PDF password Refixer

Step 2. In this result, you can see that the actual password extracted by this PDF password remover software. Here in this example, the actual password is “an” which is correctly tracked down by this software.

Guide to Unlock a Secured PDF using PDF password Refixer

Step 3. While trying to unlock PDF file without any password, you will get a message which will tell you to enter the correct password to get access into the locked PDF file. 

Guide to Unlock a Secured PDF using PDF password Refixer

Step 4. As you will enter the correct password obtained from the PDF password remover software you will notice that the encrypted PDF will open.

Guide to Unlock a Secured PDF using PDF password Refixer

Using the Smallpdf tool

This method is more straightforward than the previous method as you can perform this method without any software. To execute this method, you only require your internet connection.

Follow the steps as mentioned below to unlock PDF file that is encrypted by a password

Step 1. At first, you have to go to site and select the “unlock PDF” option at the bottom right corner of the screen. 

Guide to Unlock a secured PDF: Using smallPDF

Step 2. After selecting the “unlock PDF” option, you will go to the main page where you have to upload the password-protected PDF file. 

Guide to Unlock a secured PDF Using smallPDF

Step 3. In the next step, you have to upload the password-protected file into the site so that the website can offer you the unlocked PDF file that you can download.

Guide to Unlock a secured PDF Using smallPDF

Guide to Unlock a secured PDF Using smallPDF

Step 4. But before downloading the unlocked PDF file, you will have to check the box that is marked in the picture.

Guide to Unlock a secured PDF Using smallPDF

Step 5. After checking the box, you will be able to download the unlocked PDF file directly to the computer. 

Guide to Unlock a secured PDF Using smallPDF

Step 6. The downloading process is shown in the next picture.

Guide to Unlock a secured PDF Using smallPDF

Step 7. After downloading the unlocked PDF file directly into the computer system, you will be able to open the file without any password. Therefore this PDF password removal process is straightforward to execute and can be performed without any software. The downloaded file is not password-protected, and so you can easily open it with a single click.

Guide to Unlock a secured PDF Using smallPDF

Here is your password-protected file which is now opened

Guide to Unlock a secured PDF Using smallPDF


We can assure the user if they go through this article properly, they will be able to remove any password combination as this article is a complete guide to teach everyone how to unlock a secure PDF file with the help of the most straightforward PDF password removal techniques. If you feel this article helpful please like, share, and follow our Facebook page and keep visiting our website for such tutorials and guides.

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