9 Replies Latest reply: Aug 28, 2012 11:58 AM by Chris 1291 RSS

    How robust is PDF-Password protection? Does it also work for PDF/A?

    Chris 1291

      Several sources say that PDF passwords can be removed with appropriate software. Is this true?

      Can I also protect a PDF/A with a password? If not, how can I be sure that I can still open a regular password protected PDF in 10 years from now?

      Many thanks.

        • 1. Re: How robust is PDF-Password protection? Does it also work for PDF/A?
          Test Screen Name MVP

          PDF/A forbids document encryption, which means it forbids password protection. That is, I imagine, so you can be sure you can still open it in the future...!

          • 2. Re: How robust is PDF-Password protection? Does it also work for PDF/A?
            Alec Molloy Adobe Employee

            PDF passwords technically can be broken, but this would require a brute-force technique, which is very time consuming and cpu intensive.

             

            If you need to store PDF/A with a little more protection, perhaps try encrypting your drive?

            • 3. Re: How robust is PDF-Password protection? Does it also work for PDF/A?
              Chris 1291 Community Member

              Thanks for your prompt reply.

               

              What I meant: If PDF/A forbids document encryption, I need to use a regular PDF if I want password protection. But with a regular PDF, I wonder how confident I can be that the file can still be opened in 10 or 20 years from now.

               

              • 4. Re: How robust is PDF-Password protection? Does it also work for PDF/A?
                Chris 1291 Community Member

                @Alec

                 

                Very good idea! Thank you.

                 

                Does this mean that tools like this cannot do what they promise: [link removed - see Terms of Use 8.2]

                • 5. Re: How robust is PDF-Password protection? Does it also work for PDF/A?
                  Alec Molloy Adobe Employee

                  I know that there are tools that can do things like what this program has promised, but I am not familiar with any specifics.

                   

                  I think encrypting your drive would be the best thing to do. This would be more difficult to get past.

                  • 6. Re: How robust is PDF-Password protection? Does it also work for PDF/A?
                    try67 ACP/MVPs

                    Don't count on PDF passwords for security. There are applications available

                    online that can get through them in seconds (not using brute force). For

                    real protection use a more substantial encryption format, or invest in DRM

                    technology.

                    • 7. Re: How robust is PDF-Password protection? Does it also work for PDF/A?
                      MichaelKazlow ACP/MVPs

                      I have investigated elcom's software what it used to say is that pdf files that can be opened, but use password protection to prevent changes are pretty easy to circumvent. PDF files that require a password to open are more difficult for them to open, they use dictionary attacks and when that fails it uses brute force methods. Brute force methods are pretty successful with weak passwords for the most up to date security that Adobe offers. If you pick a truly random 64-bit security password, it will take some time to  crack it.

                       

                      As to your ability to open a secured password in 20 years from now? Heck there is no guarantee that your non-secured pdf file will be readable in 20 years. With PDF/A your chances are pretty good as it uses standards based file format, but there is no guarentee that Adobe or any other company doing business today will be in business 20 years from now.

                       

                      In general, there are no guarentees today's data will be usable 20 years from now. To be sure you can acccess needed files, you first have to make sure that every year (or five years-you decide) that you can open every needed file and its backups to be sure the file hasn't degraded. The only sure thing is that data and information degrades. You then have to ensure you have access to programs that will open the files twenty years from now. I sure woudn't want to be responsible for maintaining Windows 7 computers and their hardware to be usable twenty years from now. So to maintain usefulness, file formats and/or encryption-methods may need to be updated over the years.

                       

                      I have files from more than 25 years ago. Keeping the files usable is arduous for an individual. For a company well ...

                      • 8. Re: How robust is PDF-Password protection? Does it also work for PDF/A?
                        Dave Merchant ACP/MVPs

                        Actually PDF/A is specifically designed to guarantee that the documents can be read in the distant future (barring global destruction, end of reality as we know it, alien sheep invasions, etc.)

                         

                        While we cannot predict which vendor will be providing the software to do it, or how the data will be stored by then (holographic data mice are still in beta) the PDF/A standard is designed to do two very important things:

                         

                        1. The standard is open, so the structure of a PDF/A file can be interpreted by anyone who can open it and compare the contents to the standard (which itself is also published in PDF/A). It's basically a text file with lots of symbols in it.
                        2. PDF/A forbids any encryption or licensed algorithms (e.g. H.264) that could be impossible or illegal for a future viewer to use, for example if a password is lost or the inventor of a proprietary algorithm goes crazy and cancels all the licenses.

                         

                        Combined, these points make PDF/A impossible not to be parsable. It may end up projected directly into your brain by the aforementioned holographic data mouse, but you'll be reading it all the same.

                         

                        MichaelKazlow wrote:

                         

                        As to your ability to open a secured password in 20 years from now? Heck there is no guarantee that your non-secured pdf file will be readable in 20 years. With PDF/A your chances are pretty good as it uses standards based file format, but there is no guarentee that Adobe or any other company doing business today will be in business 20 years from now.

                        • 9. Re: How robust is PDF-Password protection? Does it also work for PDF/A?
                          Chris 1291 Community Member

                          A great thanks to all of you for your valuable answers.

                           

                          Best regards from Switzerland!