Question by jerry M: How to decrypt passwordless PDF file using Linux tools?
I have a PDF file that is internally encrypted, yet completely public and can be opened by anyone.

How to decrypt it and create the equivalent without any encryption? (all streams/strings are decrypted buy otherwise the same)

If it’s publicly viewable without password it must be possible without knowing any password.

I tried pdftk but it asks for OWNER password.

Best answer:

Answer by Trev B
First try xpdf-utils. If you are using a distribution of Linux such as Ubuntu, simply do a quick: “apt-get install xpdf-utils”.

All the information about xpdf-utils is located at the website I referenced as a source (townx.org citation).

Second, there is pdfcrack. They have a page on Sourceforge which I provided as a second source.

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