9 Replies Latest reply on Jul 15, 2011 6:23 AM by marta tempo

    help decrypting a PDF

    marta tempo

      I am running Windows 7, 64-bit and Adobe Reader X.  A colleague mailed me a CD with a compressed/ZIP folder containing individual PDF files encrypted with a password (for security - the files contain proprietary info).  I was given the password in a separate email.   I can unzip the folder and see the individual PDF files - their names, date and time created, size, and opposite each file in the "password" column it says "yes".   I cannot open any of the PDF's.  Double-clicking each file does not prompt me for the password.  Using File, Open, does not work.  Tried File, remove password, and I get a dialog box with a place to type a password, but after typing the password I was given, I get an error message saying the file cannot be opened.  From within Adobe reader, if I navigate to the files, then try using File, Open, I still cannot open these PDFs.  Any ideas?

        • 1. Re: help decrypting a PDF
          Bernd Alheit Adobe Community Professional & MVP

          Using File, Open, does not work.

          What happens when you try this?

          • 2. Re: help decrypting a PDF
            waflgnog Level 1



            Did you really unzip the PDF files to e.g. a folder on your local hard disk or did you only open the archive using e.g. WinZip without actually having extracted the files?


            I guess the ZIP archive is password protected, not each individual PDF file in it. So, you should try to extract the files to your hard disk and then you might be prompted for the password.


            BTW, that password column you mentioned seems to be a proof for my guesswork

            • 3. Re: help decrypting a PDF
              marta tempo Level 1

              Thank you for your input.  I did wonder if I had really extracted these PDF files or not.  I did expect a password prompt to show up when I first chose "extract" from the menu, but I only get an error message.


              According to the Help menu, to extract these compressed, password protected files from the compressed folder, I should do one of these two things:


              "Locate the compressed folder that you want to extract files or folders from.

              Do one of the following:


              1) To extract a single file or folder, double-click the compressed folder to open it. Then, drag the file or folder from the compressed folder to a new location.


              2) To extract the entire contents of the compressed folder, right-click the folder, click Extract All, and then follow the instructions."


              I have tried both of these options and neither works.  When I use the "extract" command, I get a couple of error dialog boxes, depending on what command I chose (extract or extract all):

              Either - "Windows cannot complete the extraction. The destination file could not be created."

              Or - "an unexpected error is keeping you from copying the file.  If you continue to receive this error, you can use error code search for help with this problem."  Error code is: 0x8004005 Unspecified Error.


              So I am stumped.  When  I highlight one of the PDF files, then go to the File drop down menu (Windows 7 Explorer), there is a "password" link that opens up another box in which to type a password, but I just get an error code again that says: "File skipped unknown compression method."


              Again, thanks for anyone's input!

              • 4. Re: help decrypting a PDF
                waflgnog Level 1

                First of all, I doubt that this is an issue with Adobe Reader.


                Please ask your colleague how he built the archive, i.e. which program (version) and options he used. Maybe the Windows integrated "ZIP program" is not able to decrypt a password protected archive, e.g. created with WinZip or 7-zip and using strong encryption.

                • 5. Re: help decrypting a PDF
                  Claudio González Most Valuable Participant

                  Marta, sorry for butting in and asking what may be an impertinent question, but I am not at all sure that you have copied the zipped file to your hard disk before attempting decompressing it and opening the files. Have you?

                  • 6. Re: help decrypting a PDF
                    marta tempo Level 1

                    NO Prob about the question.  I have copied the compressed

                    folder-containing-pdf files onto my hard drive and taken the CD that they

                    were on out of my CPU.  On my hard drive, I can open the compressed folder

                    and "see" all the PDF files - their names, their size, the time they were

                    created, and a column titled "password" has a "yes" next each and every one

                    of these 250 files.  I cannot "extract" or open these files further from

                    here.  As I said, I can right click the folder and chose "extract all" and I

                    get an error message (detailed in a just posted reply), or I can right click

                    the individual PDF files and try extracting them separately, and I still get

                    an error message.


                    I have put this same disk into an older computer we have, running Vista and

                    Adobe Reader 9 or 8 maybe, and I get the exact same problem and the exact

                    same error messages when trying to open or extract these password-protected


                    • 7. Re: help decrypting a PDF
                      Claudio González Most Valuable Participant

                      Then I would follow wstoll's last advise.

                      • 8. Re: help decrypting a PDF

                        The error is the result of encrypting the files with AES-256 (not supported by Windows) instead of ZipCrypto (supported by Windows).


                        You can download 7-zip from 7-zip.org for free and extract the files.

                        • 9. Re: help decrypting a PDF
                          marta tempo Level 1

                          Thanks to everyone for the ideas about decrypting these files.   We've decided to meet in person so that I can pick up a new disk with non-encrypted files on it.

                          John1400, when I see the person who encrypted the files, I'll ask him if he used AES-256 to encrypt.  It would be nice to be able to confirm what the problem was.