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A
ALAINDC
Participant
July 6, 2011
Question

HOW TO DETECT A MODIFIED PDF FILE

  • July 6, 2011
  • 3 replies
  • 220915 views

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

    This topic has been closed for replies.

    3 replies

    I
    IndianTechSup22230449aipj
    Participant
    December 13, 2021

    You can use a checksum by right click and then crc sha, its not a guarante, but if its the same its probably the same

     

    370H55V
    370H55V
    Inspiring
    July 6, 2011

    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?

    MichaelKazlow
    MichaelKazlow
    Legend
    July 6, 2011

    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.

    J
    Joseph364176090e93
    Participant
    March 30, 2024

    Hey. Hope you can help.

     

    If I sign it will the document update itself to say I have signed it?  For example: I have a print of a pdf supplied to me. On the last page it says :

    Signed electronically by both parties 

     

    Hope you can help 

    S
    sprinklr-integration-user
    Inspiring
    April 9, 2024

    Hi @Joseph364176090e93,

     

    Hope you are doing well. Thanks for writing in!

     

    If you have signed the file, it will be changed to a read-only version. Also, if you have the file signed using a digital certificate, you can check its authenticity. More info here: Validating digital signatures, Adobe Acrobat

     

    Hope this helps.


    -Souvik

     

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