Sometimes, I receive digital invoices in PDF format with a password. That way I shouldn't be able to modify them and commit fraud. Unfortunately, this also makes it impossible to perform normal operations on them, such as removing unneeded specifications or merging all invoices into one single file.
Luckily, most Linux distributions come with a tool that can be used to remove these passwords: ghostscript.
In order to remove the password, simply run:
gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=unencrypted.pdf -c .setpdfwrite -f encrypted.pdf
While this does remove the password, I'm not sure if it does not degrade the quality of the file a little (I don't notice any quality difference, but if you use highres files, you may lose quality).© GeekLabInfo How to decrypt a PDF file on Linux is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to http://www.geeklab.info