Index
- Preliminary information
- How to open password protected PDF files for free
- How to open password protected PDF files online
- App to open password protected PDF files
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 should know that, depending on the type of protection applied to PDFs, the password used for them can be of two different types: there is the owner password which protects files against printing or modification and the user password which, on the other hand, prevents the opening of documents by those who do not know the exact keyword.
The owner password can be bypassed quite simply, usually it only takes a few seconds, 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 e 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 doesn't have a graphical interface and must be used from the command line, but don't worry: it's pretty intuitive.
To download QPDF to a PC Windows, go to the page dedicated to the program on the SourceForge website and click on the button Download Latest Version present in high to sinistra.
When the download is complete, extract theZIP 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 key Shift on the keyboard, right click on the folder bin present in the folder where you extracted QPDF and select the item Open command window here give the menu to compare.
Now that you see the Command Prompt window on the screen, enter the string qpdf --decrypt input.pdf output.pdf (instead of input.pdf e output.pdf you have to type the full path of the PDF to be unlocked and the output file to be obtained) and press the key Submit on the keyboard. After doing this, you will get an unlocked version of the PDF in the folder you indicated for the output file.
Se, invece, stai 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 terminal. So, first open the Terminal, selecting the relevant one icon (Quella with the nether finest in the riga di codice) found in the folder Other of Launchpad.
After displaying the Terminal window on your 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 key Submit on the keyboard and by entering the Password Mac administration. Then, to install QPDF, enter the command brew install qpdf, always followed by pressing the Submit.
When installation is complete, enter the command qpdf --decrypt input.pdf output.pdf in the Terminal (instead of input.pdf e output.pdf you have to type the paths of the input and output files) and, within 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, open source 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 link Download(pdfcrack-xx.zip, xxk) located in the right sidebar.
Once the download is complete, open theZIP archive obtained, extract the contents into a folder of your choice and start the Command Prompt, facendo click sul Start button (I cheer with the windows flag) che trovi nella part in fund to sinistra della taskbartyping "Prompt" in the displayed search field and selecting the relevant colleague in the list.
Once the Command Prompt window appears on the screen, issue the command CD "[PDFCrack folder]" (instead of [PDFCrack folder] you must enter the complete path of the folder where you extracted PDFCrack) followed by pressing the key Submit on the keyboard. Next, enter the pdfcrack command "file.pdf" (in place of file.pdf you have to enter the complete path and name of the file to be decrypted), always pressing the key Submit.
Once this is done, PDFCrack will begin to "attack" the document to look for its password. When this is identified, you will see the writing appear found user-password, followed by the password needed to open the file.
Se, invece, stai using MacOS, to use PDFCrack visit the page dedicated to the program on the SourceForge website and click on the button Download Latest Version, placed at the top.
Once the download is complete, open the archive tar.gz obtained and extract the contents into a folder of your choice. Then open the terminalby selecting the relevant icon (Quella with the nether finest in the riga di codice) found in the folder Other of Launchpad and issue the command cd [PDFCrack folder] (instead of [PDFCrack folder] you must enter the complete path of the folder where you extracted PDFCrack), followed by pressing the key Submit on the keyboard. Then, enter the command “make f Makefile, always followed by pressing the key Submit.
Once the above steps have been completed, open a new Terminal window, enter the command [PDFCrack folder] / pdfcrack -u "file.pdf" (instead of [PDFCrack folder] you have to enter the full path to the folder where you extracted PDFCrack and instead of file.pdf you have to enter the full path and name of the file to decrypt), press the key Submit on the keyboard and you will 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 installed on Windows, you can open user password protected PDF files by contacting Free PDF Unlocker: it is a free software, easy to use and able to perfectly fulfill the purpose for which it is set up, creating a copy of the document that is given “at meal” free from any kind of limitation.
To download it to your computer, visit the program's website and click on the button Download, located at the bottom, then select the link Download your file.
Once the download is complete, open the .exe file obtained and click the button Yes in the window that appears on the desktop. Next, click on the button first Next, three consecutive times and then on those install e Finish. If you see a warning that you need to install the Microsoft. NET Framework 3.5, you also agree to this, as it is essential for the correct functioning of the program.
Then start the program by clicking on the relevant one collegamento which was added to the Start menu and, once the Free PDF Unlocker window is displayed on the desktop, click on the button Add File located at the top, to select the file to unlock.
Then press the button KATEGORIEN, to indicate the location on the PC where you want to save the output file and start the procedure by clicking on the button Unlock 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
You do not want or cannot download new programs to your computer and would therefore like to understand if there are tools for open password protected PDF files online? Of course, yes and below you will find some of the best ones.
Soda PDF Online
The first, among the web tools, that I want to advise you to try is Soda PDF Online: this is a service that provides several useful functions for working on PDF documents, including, of course, a tool for unlocking PDFs protected against printing and modifications. 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's servers are removed within a maximum period of 24 hours.
To use Soda PDF Online, go to the service web page and drag the PDF of your interest to it. Alternatively, click on the button Choose file and upload the files "manually". You can also get your PDFs from Google Drive or dropbox, by first clicking on the buttons with i logos of services.
Ad upload avvenuto, fai clic sul pulsador Unlock and wait for the password to be removed from the PDF. Then click on the button Download and View in Browser, to start the download procedure of the final document and open it online, through 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 changes 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, eventually, 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 going to act in the browser window. Alternatively, click on the button Select PDF file and select "manually" the document, or take it from Google Drive or from dropboxby clicking the relevant buttons.
When upload is complete, click on the button Unlock PDF appeared below and wait for the download of the document without password to be completed. If the download does not start automatically, click on the button Download the unlocked PDFs to "force it". Alternatively, you can save the final file to Google Drive, dropbox or you can share theURL 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 a few Whatsapp which you can use to open password-protected PDF files using your smartphone or tablet, both on Android that of iOS. Find listed what I believe to be the best in the category right below.
PDF Utilities (Android)
Stai using a smartphone or tablet Android, I recommend that you consider using PDF Utilities: this is a free app that allows you to delete the password used to protect PDFs from content modification. 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 button Install. Then, start the app by tapping on the button apri comparso sullo schermo oppure selecting the relative icon which has been added to the home screen.
Now that you see the main application screen, tap the button with the three lines horizontally located at the top left and select the option Remove write-protection give the menu check if you press.
At this point, award your bottone Select and select the PDF you are interested in going to act, first granting the app the necessary permissions to access the files on the device.
Then, click on the button Home and wait a few moments for the application to process the document. Afterwards, a new unlocked file will be created and saved in the same location as the original one.
PDF Unlocker (iOS)
If you are using a iOS, I suggest you use the app instead PDF Unlocker. It's 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, keep in mind that you need to know the password used to protect the document.
To download and install it on iPhone or iPad, visit the relevant section on the App Store, press the button Get, quindi quello Install and authorize the download via Face ID, touch ID o Password Apple ID. Then click on the button apri appeared on the screen to start the app, or select the relevant one icon which has been added to the home screen.
Now that you see the main screen of the application, click on the button Home, quindi quello Choose File and select il PDF document in relation to which you are interested in going to act. Afterwards, tap on the button Upload File.
Therefore, type the Password used to protect the PDF in the appropriate field and press the button Convert File. Once the PDF is unlocked, click on the button Download File that you see appear on the display and indicate the location where you want to save the document without password, or the app where you want to export it.
How to open password protected PDF files
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