Good morning friends,
Debian 10 server
I have always prevented 'pdf' files from being modified with
# pdftk [1.pdf] output [2.pdf] owner_pw "pass"

Today I found this instruction that cracks the password:
# gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=unencrypted.pdf -c .setpdfwrite -f encrypted.pdf

Any ideas to protect the 'pdf'
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Buenos dias amigos,
desde siempre evité que se modificaran archivos 'pdf' con
# pdftk [1.pdf] output [2.pdf] owner_pw "pass"

Hoy encontre esta instruccion que revienta el password:
# gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=unencrypted.pdf -c .setpdfwrite -f encrypted.pdf

Alguna idea para proteger los 'pdf'

Does not appear to crack a pdf I just tried.
comes back with
Error: /undefined in .setpdfwrite

1. What version of gs you have installed?
2. Try encrypting with qpdf?

Yvesjv, thanks for your interest


angel@histori:~$ gs
GPL Ghostscript 9.27 (2019-04-04)
Copyright (C) 2018 Artifex Software, Inc. All rights reserved.
This software is supplied under the GNU AGPLv3 and comes with NO WARRANTY:
see the file COPYING for details.
GS>
...........................
angel@histori:~$ pdftk -version
pdftk port to java 3.0.2 a Handy Tool for Manipulating PDF Documents
Copyright (c) 2017-2018 Marc Vinyals - https://gitlab.com/pdftk-java/pdftk
Copyright (c) 2003-2013 Steward and Lee, LLC.
pdftk includes a modified version of the iText library.
Copyright (c) 1999-2009 Bruno Lowagie, Paulo Soares, et al.
This is free software; see the source code for copying conditions. There is
NO warranty, not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
..................................................................
angel@histori:~$ uname -a
Linux histori 4.19.0-23-686-pae #1 SMP Debian 4.19.269-1 (2022-12-20) i686 GNU/Linux

bash-5.2$ gs -v
GPL Ghostscript 9.56.1 (2022-04-04)
Copyright (C) 2022 Artifex Software, Inc. All rights reserved.

pdftk is not installed and neither is the java version.
Can you repost your question in the security forum?

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1 members found this post helpful.

Thanks, didn't know that's the established procedure.