Written by Amit Agarwal on Wednesday, January 24, 2007
How to Open Password Protected PDF Documents
There are sometimes genuine reasons to unlock or crack a password protected PDF file. You have the legal right to open the encrypted PDF document but forgot the password like in the case below.
Say one of your former colleague created some critical sales reports in PDF format but he is not working with the company anymore. In his absence, you have no option but to crack the PDF password in order to open, read or print these PDF files.
There are basically two types of PDF protection - the original PDF creator can either restrict opening the PDF file itself or he can restrict others from modifying, printing or copying text and graphics from the PDF file. Here are a few possible workarounds:
When there are Copying or Printing Restrictions..
Say you want to print a couple of pages from the PDF document but the document settings won't let you do that.
Open the document in Acrobat Reader or Foxit and capture the PDF page as an image using any free screen capture software. If there are multiple pages, you may try SnagIt since it can autoscroll and capture multiple pages of the document in one-go.
If you want to copy just a portion of text from some PDF page, use a screen capture tool with OCR features (like Kleptomania, Capture Text discussed here)
Alternatively, you can invest in commercial solutions like Advanced PDF Password Recovery from ElcomSoft and PDF Password Remover from Very PDF.
(These utilities may not recover the password for you - they'll just remove the restrictions from the password protected file)
When there are Document Opening Restrictions..
This is a very tricky case and there's no straight-forward solution to read PDF documents that are password-protected at the Open level.
The software will use methods like Brute Force, Key Search and Dictionary Attack to guess the password. They will try to use all possible character combinations as the password and so the process might take hours or even days and would really depend on your computer's processing power.
Advanced PDF Password Recovery Professional edition from ElcomSoft is a recommended option. When (if) the password is found, the program shows it, as well as the number of passwords which have been tested, and the program speed.
Legal Issues: - you maybe surprised to learn that these PDF password cracking software are absolutely legal and Microsoft even awarded ElcomSoft a Gold Certified Partner status.
Related: Remove Watermarks from Adobe PDF Documents
Reader Comments:
Written by Prasanna Narayanan at 24/1/07 6:03 PM
Is there a way like this to open password protected excel sheet
Written by Best Desi at 24/1/07 10:32 PM
Wow i dint know they are legal thanks for the info :) good as always.
Regards
Written by Anonymous at 27/1/07 9:45 PM
I have a PDF file that is protected with a password. It's actually a magazine scanned in PDF which I downloaded from some book warez site. I tried the brute force method to crack the pdf password but it's takign some time. Will post if the process is successful.
Written by Anonymous at 28/1/07 4:19 AM
You know those sites post the password in the item description/NFO file right?
Written by StandAlone at 28/1/07 10:28 AM
If the needs is printing the pdf document, i think we can use pdf-to-words converter.
Then we print it in words.
how it can be done?
we can use zamzar[dot]com or any commercial converter tools.
Written by brenton at 28/1/07 12:40 PM
Doesn't help for e-books that you happened to purchase on one copy of windows, and then had to do a reinstall. D: I hate DRM. :(
Written by D Nickull at 29/1/07 12:59 PM
Cracking with the brute force method will likely not work in your lifetime. PDF encryption in later versions uses the AES encryption algorithm in the 128 bit strength. I have written a few blog articles on this subject.
Written by Anonymous at 29/1/07 8:17 PM
On Mac OS X you can open your pdf in ColorSync and resave as pdf and it will remove any password protection. This does not work on pdfs that require password to open them. ColorSync is a free utility included with all versions of OS X.
Written by Anonymous at 29/1/07 9:33 PM
I had a document that didn't allow printing to any network printer or to Cute PDF. It would only print to a device on LPT1 and only if the print driver was not set to "print to file." The way I got around it in Windows was to set up an HP LaserJet 4 Postscript as my LPT printer but not have anything hooked to the printer port. I set the printer driver to raw and then printed the document. The raw postscript file will then be queued in C:\WINDOWS\system32\spool\PRINTERS . Grab that file, open it with Ghostscript, convert to PDF and BAM! you have a PDF with no DRM. Then do a little dance and feel crafty, baby, crafty!
Written by Anonymous at 30/1/07 3:23 PM
IF you just want to print a PDF document that does not allow printing instead of the screen capture method use a toold like omniprint that converts PDF documents to highres images and print those (or OCR those)
google "omniformat"
Written by Pavel at 5/2/07 3:54 PM
In addition of commercial tools
mentioned above I've found the almost free PDF password remover software - GuaPDF. The author just asks for a link to his site.
Written by Anonymous at 12/2/07 5:34 AM
@ D Nickull, who wrote
"Cracking with the brute force method will likely not work in your lifetime."
That would be true if the Password crackers were going after the raw document key* actually used to encrypt the PDF file. However the utilities cited in this article are going after the passwords which are considerably weaker. Most people choose passwords that are 6-8 characters in length and are printable ASCII which limits the keyspace and makes brute force searching computationally feasible.
BTW it doesn't matter for RC4 and AES the key derivation function for Password Security is the same.
Written by Navin at 18/2/07 12:58 AM
i m a mac user and i have a password protected pdf file how can i break the passwoed if i don't know the password plz help
Written by tom at 8/4/07 4:47 PM
you could also try opening the pdf with gsview and then converting to another pdf without protection (file > convert > pdfwrite). i've done this before using a time-protected pdf which had timed out (acrobat gave a green screen and the new pdf [after using gsview] was then viewable in acrobat).
you'll need to install ghostscript first, then gsview (search google for them).
Written by Anonymous at 29/5/07 2:45 PM
i have a pdf document which is password protected for opening. its a file created by my colleague and he has left the organization.now i am in commotion as it is pretty urgent and my job depends over it...can u help me????
Written by ravik at 20/6/07 8:32 PM
You can convert your pdf file to a ps file and then convert it back to a pdf file.
Linux comes with pdftops and pstopdf inbuilt commands. On Windows, you can use ghostscript or the GUI solution FreePDFXP which needs ghostscript to be installed anyway.
Written by tbone at 28/6/07 2:58 AM
I use Brava! Reader (it's FREE)to by-pass print restrictions of PDFs. What I do is open the protected PDF in Brava! Reader and reprint the file as a new PDF. It works everytime.
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