4 Replies Latest reply on Jul 6, 2011 2:01 PM by Bernd Alheit

    HOW TO DETECT A MODIFIED PDF FILE

    ALAINDC Level 1

      Hello everyone,

      I re-post this message because I've found a way to detect that a file as been modified . I found that any modification may corrupted the cross reference table & it's easily detect with "bycepdfdata" , a software that shows metadata.... But I don't know if it do detect a file modified with acrobatpro ? Your opinion ?

       

      Thank you

        • 1. Re: HOW TO DETECT A MODIFIED PDF FILE
          MichaelKazlow MVP & Adobe Community Professional

          There is no sure proof way to determine if a generic pdf file is modified. If you go to the document properties (control or command d), if the proper metadata is available, it will list the creation date and time and modified date and time. This can help you determine if a pdf file has been modified since creation. However, it is not foolproof. This metadata is not secured. The easiest way to detect if a file has been modified to to digitally sign the document. Reader and Acrobat will report if the document has been changed since it was signed.

          • 2. Re: HOW TO DETECT A MODIFIED PDF FILE
            ALAINDC Level 1

            The easiest way to detect if a file has been modified to to digitally sign the document.

            But in case of a non digitally signed doc , you can detect if the cross ref table as been corrupted by using the software amention above .

            My question was : when you modify a pdf with adobe arc pro , does it corrupted the ref table ?

            • 3. Re: HOW TO DETECT A MODIFIED PDF FILE
              370H55V Level 4

              As I understand it, if you modify (edit) a PDF with Acrobat Pro, it will create a new reference table on save that coincides with the changes made. At that point a new "created" date is applied.

               

              If you don't want anyone to modify your PDFs, why not just lock and password protect them?

              • 4. Re: HOW TO DETECT A MODIFIED PDF FILE
                Bernd Alheit Adobe Community Professional & MVP
                My question was : when you modify a pdf with adobe arc pro , does it corrupted the ref table ?

                No.