How to open password protected PDF files

Go in a hurry. Before going to the office you want to print a PDF received by email but, at the very best, you realize that you can’t do it because the file is protected by a password against changes. And now? Well, use one of the resources to open password-protected PDF files that you find in this guide of mine and you will see that you will be able to cope with it in no time.

In the following lines, in fact, you will find a bunch of programs, online services and apps useful for the purpose in question, usable without the slightest problem through those that are the most popular operating systems, all completely free (at least basic). How do you say? This seems to be interesting but, not being you particularly expert in new technologies, are you afraid that the resources to be used are too complex for you? Well, know that you are wrong … and very wrong too! The tools I’m going to talk to you about, in fact, can be exploited without the slightest effort by anyone, even those who, a bit like you, don’t really consider themselves a great expert in IT and new technologies.

Then? May I know what are you still standing there? Make yourself comfortable, take a few minutes of free time just for you and immediately start concentrating on reading what is written below. I sincerely hope that, in the end, you can feel very happy and satisfied with what you have learned. Now, however, just chat and let’s take action. Happy reading and good “work”.

Index

• Preliminary information
• How to open password-protected PDF files for free
  • QPDF (Windows / macOS / Linux)
  • PDFCrack (Windows / macOS)
  • Free PDF Unlocker (Windows)
• How to open password-protected PDF files online
  • Soda PDF Online
  • iLovePDF
• App to open password-protected PDF files
  • PDF Utilities (Android)
  • PDF Unlocker (iOS)

Preliminary information

Before getting to the heart of the topic, going to explain how to open password-protected PDF files, it is my duty to make some clarifications regarding the implementation of this procedure.

You must know that, depending on the type of protection applied to PDFs, the password used for the same can be of two different types: there is the owner password which protects the files against printing or modification and the user password which, instead, prevents the opening of documents by those who do not know the exact keyword.

The owner password can be bypassed quite simply, usually a few seconds are enough, while the user password is much more difficult to bypass. In this second case, in fact, it is necessary to carry out a brute force attack on the document, thus trying all the possible combinations of characters until the right one is found, which can take hours, or even days.

How to open password-protected PDF files for free

Having made the necessary clarifications above, let’s get to the point and let’s find out, concretely, how to open password-protected PDF files using some special free programs, for Windows, macOS and Linux. To find out more, please continue reading: you will find them indicated below.

QPDF (Windows / macOS / Linux)

The first program I want to recommend is  QPDF, which is free, open-source and works on both Windows and macOS and Linux. It is very effective and only unlocks PDFs that are protected from printing and editing. Unfortunately it does not have a graphical interface and must be used from the command line, but don’t worry: it is quite intuitive.

To download QPDF on a Windows PC, go to the page dedicated to the program on the SourceForge website and click on the Download Latest Version button at the top left.

When the download is complete, extract the ZIP archive obtained in any folder and start QPDF using the Command Prompt, directing it directly to the folder that contains the program: to do this, hold down the Shift key on the keyboard, right-click on the bin folder present in the folder where you extracted QPDF and select the item Open command window here from the menu that appears.

Now that you see the Command Prompt window on the screen, enter the string qpdf –decrypt input.pdf output.pdf(instead of input.pdf and output.pdf you have to type the full path of the PDF to be unlocked and the output file to be obtained) and hit the Enter key on the keyboard. After doing this, you will get an unlocked version of the PDF in the folder you indicated for the output file.

If, on the other hand, you are using macOS, to download and install QPDF you have to rely on Homebrew, a free and open source package manager that allows you to install various types of software from the Terminal. So, first of all open the Terminal, selecting the relative icon (the one with the black window and the line of code ) that you find in the Other folder of the Launchpad.

After displaying the Terminal window on the desktop, to install Homebrew, issue the command  /usr/bin/ruby -e “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)”, followed by pressing the Enter key on the keyboard and entering the Mac administration password. Then, to install QPDF, enter the command brew install qpdf, always followed by pressing the Enter key.

When the installation is complete, enter the command in the Terminal qpdf –decrypt input.pdf output.pdf(instead of input.pdf and output.pdf you have to type the paths of the input and output files) and, in a short time, you will get an unlocked version of the PDF of your interest. It was easy, wasn’t it?

PDFCrack (Windows / macOS)

If you need to open a PDF file protected by a user password (therefore opening password), one of the best tools you can rely on is PDFCrack: it is a no-cost program, running on Windows and macOS, of an open-source nature and very effective. Even in this case, however, we are in the presence of a resource that can be used only and exclusively from the command line.

To download it on Windows, go to the program’s website and click on the Download link  ( pdfcrack-xx.zip, xxk) located in the right sidebar.

When the download is complete, open the ZIP archive obtained, extract the contents in a folder of your choice and start the Command Prompt, by clicking on the Start button (the one with the Windows flag ) that you find in the bottom-left part of the toolbar applications, by typing  “prompt” in the displayed search field and selecting the relevant link in the list.

Once the Command Prompt window is displayed on the screen, issue the command  CD “[cartella PDFCrack]”(instead of [PDFCrack folder] you must enter the full path of the folder where you extracted PDFCrack) followed by pressing the Enter key on the keyboard. Subsequently, enter the command pdf crack “file.pdf”(instead of file.pdf you must enter the complete path and the name of the file to be decrypted), always pressing the Enter key.

Once this is done, PDFCrack will start “attacking” the document to look for its password. When this is found, you will see found user-password appear, followed by the password needed to open the file.

If, on the other hand, you are using macOS, to use PDFCrack visit the page dedicated to the program on the SourceForge website and click on the Download Latest Version button at the top.

Once the download is complete, open the tar.gz archive obtained and extract the contents in a folder of your choice. Then open the Terminal, selecting the relative icon (the one with the black window and the line of code ) that you find in the Other folder of the Launchpad and issue the command  (instead of [PDFCrack folder] you have to enter the complete path of the folder in which you PDFCrack extract), followed by pressing the Enter key on the keyboard. Then, enter the command “make, always followed by pressing the Enter key .cd [cartella PDFCrack]f Makefile

Once the above steps have been completed, open a new Terminal window, enter the command  [cartella PDFCrack]/pdf crack -u “file.pdf”(instead of [PDFCrack folder] you must enter the complete path of the folder where you extracted PDFCrack and instead of file.pdf you must enter the path complete and the name of the file to be decrypted), press the Enter key on your keyboard and you will be able to know the password of your PDF.

Free PDF Unlocker (Windows)

If you prefer to contact a program with a user interface and if you use a PC with Windows installed, you can open the PDF files protected by a user password by contacting Free PDF Unlocker: it is free software, easy to use and able to fulfill perfectly for the purpose for which it is in charge, creating a copy of the document that is given to him “at meal” free from any type of limitation.

To download it to your computer, visit the program’s website and click on the Download button, located at the bottom, then select the Download your file link.

When the download is complete, open the .exe file obtained and click the Yes button in the window that appears on the desktop. Subsequently, click first on the Next button, three consecutive times and then on that Install and Finish. If you see a warning appearing that Microsoft .NET Framework 3.5 must be installed, you also agree to this, as it is essential for the program to function correctly.

Next, start the program by clicking on the relative link that has been added to the Start menu and, once the Free PDF Unlocker window is displayed on the desktop, presses the Add File button at the top, to select the file to be unlocked.

Then press the Browse button to indicate the location on the PC where you want to save the output file and start the procedure by clicking on the Unlock button located at the top. At the end of the process, if the password is identified, it will be shown on the screen.

How to open password-protected PDF files online

Don’t want or can’t download new programs to your computer and would like to know if there are any tools to open password-protected PDF files online? But of course yes and below you will find some of the best.

Soda PDF Online

The first, among the Web tools, that I want to advise you to try is Soda PDF Online: it is a service that provides several useful functions to intervene on PDF documents, including, of course, also a tool for unlocking protected PDFs. against press and changes. It is free, can be used from any operating system and browser and there is no registration required. It should also be noted that all files uploaded to the service servers are removed within a maximum period of 24 hours.

To use Soda PDF Online, go to the service’s web page and drag the PDF of your interest to it. Alternatively, click on the Choose file button and upload the files “manually”. You can also get your PDFs from Google Drive or Dropbox by first clicking on the buttons with the service logos.

Once uploaded, click the Unlock button and wait for the password to be removed from the PDF. Then, click on the Download and View button in the browser, to start the download procedure of the final document and open it online, using the special viewer offered by the service.

iLovePDF

Another good online service you can refer to is iLovePDF. It’s free, allows you to create, edit, convert and unlock PDFs that are protected against printing and modifications and works from any browser and operating system, without registration. It allows you to upload files with a maximum size of 100 MB and protects the privacy of users by removing, within a few hours, the documents that are uploaded to its servers. It should be noted that, if necessary, it is possible to subscribe to one of the paid plans (starting from 6 euros/month) to access extra functions, such as increasing the maximum size for uploading files to 1 GB.

To use the service, go to its home page and drag the document you are interested in to go to act in the browser window. Alternatively, click on the Select PDF file button and select “manually” the document, or download it from Google Drive or  Dropbox, by clicking on the relevant buttons.

Once the upload is complete, click on the Unlock PDF button that appears below and wait for the download of the document without a password to be completed. If the download does not start automatically, press the Download unlocked PDF button to “force it”. Alternatively, you can save the final file on Google Drive, Dropbox or you can share the URL with other users by clicking on the appropriate buttons located on the right.

App to open password-protected PDF files

To conclude, I would like to point out some apps that you can use to open password-protected PDF files using your smartphone or tablet, both on Android and iOS. Find listed what I believe to be the best in the category right below.

PDF Utilities (Android)

If you’re using a smartphone or tablet Android, you should consider the use of PDF Utilities: This is a free app that lets you delete the password used to protect PDF from content editing. Note that it also allows you to edit documents by removing and adding pages.

To download and install it on your device, visit the relevant section on the Play Store and press the Install button. Then, start the app, by tapping the Open button that appeared on the screen or by selecting the relative icon that has been added to the home screen.

Now that you see the main application screen, tap on the button with the three lines horizontally located at the top left and select the Remove write-protection option from the menu that opens.

At this point, press the Select button and select the PDF you are interested in taking action, first granting the app the necessary permissions to access the files on the device.

Then, press the Start button and wait a few moments for the application to process the document. Later, a new unlocked file will be created and saved in the same location as the original one.

PDF Unlocker (iOS)

If you are using an iOS-based device, I suggest you use the PDF Unlocker app instead. It is free, easy to use and allows you to intervene on password-protected documents that cannot be viewed through other apps as they must first be unlocked. In that case, however, note that you need to know the password used to protect the document.

To download and install it on your iPhone or iPad, visit the relevant section on the App Store, press the Get button, then click the Install button and authorize the download via Face ID, Touch ID or Apple ID password. Then, press the Open button that appears on the screen to start the app, or select the relative icon that has been added to the home screen.

Now that you see the main application screen, click on the Start button, then on the Choose File button and select the PDF document you are interested in taking action. Afterwards, tap on the Upload File button.

Type, therefore, the password used to protect the PDF in the appropriate field and press the Convert File button. Once the PDF is unlocked, press the Download File button that you see appear on the display and indicate the location where you want to save the document without a password or the app where you want to export it.