Answered on 22.05.2019, 18:57. If you didn't get it, then look in the mailing list archives.

Tilman

Am 19.06.2019 um 09:36 schrieb rjc2...@gmail.com:
Appreciate any help on this.
I came across following post at iText tech support faq talking about similar 
topic.
https://itextpdf.com/en/resources/faq/technical-support/itext-7/how-decrypt-pdf-document-owner-password

Seems the following PDF file which they have shared is encrypted and does not 
allow to overwrite the owner password using PDFBox (2.0.15).
http://gitlab.itextsupport.com/itext/sandbox/raw/master/resources/pdfs/hello_encrypted2.pdf

How does this works and are there any similar implementation in PDFBox.

Thanks

On 2019/05/22 01:28:36, RJC 2009 <rjc2...@gmail.com> wrote:
Thanks Tilman Hausherr and Marc Kaufman for your time & help.

I came across following post at iText tech support faq talking about
similar topic.
https://itextpdf.com/en/resources/faq/technical-support/itext-7/how-decrypt-pdf-document-owner-password

Seems the following pdf file which they have shared is encrypted and does
not allow to overwrite the owner password using PDFBox (2.0.15).
http://gitlab.itextsupport.com/itext/sandbox/raw/master/resources/pdfs/hello_encrypted2.pdf

I'm just wondering how does this works and are there any similar
implementation in PDFBox.

On Wed, May 22, 2019 at 7:45 AM Marc Kaufman <m...@eeph.com> wrote:

Which is, of course, a violation of the "agreement" between PDF and
Readers (ignored by everyone, it seems, except Adobe). In
Acrobat/Reader, you need to open with the Owner password in order to
change permissions. Opening with the User password should honor
permissions and not allow changing of permissions.

Marc

On 5/21/2019 9:42 AM, Tilman Hausherr wrote:
Am 17.05.2019 um 09:47 schrieb RJC 2009:
Here is my test program which is trying to disable the printing
option and
protect the document with an owner password.

However, if I use the resultant PDF and run the program again with a
DIFFERENT owner password then it ENABLE the printing option.



Basically I need to disable the printing option in PDF with an owner
password and the printing option cannot be enabled back without using
the
original owner password.

I should have read the text more carefully (and continue reading after
"2.0.5"). This is by design. When you open with the user password then
the file is decrypted and can be manipulated, reencrypted, everything.
The owner password is just an extra so that a software can decide that
you're the owner. That is why there are so many tools on the internet
that allow to change the permissions of PDF files.

Read also this:

https://www.cs.cmu.edu/~dst/Adobe/Gallery/anon21jul01-pdf-encryption.txt


Tilman


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