How to remove the password from a PDF?

Question

I have a password protected PDF file. I know the password but in order to share the file, I have to remove the password from the PDF and share an unprotected copy. How can I do this in Ubuntu with or without the GUI?

Answer 1

The easiest way GUI (recommended for novice)

Open the protected file and use ctrl+p or use print option to print the file, now save the file as pdf.

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Using Command line

If you have pdftk already installed you can skip step1

Step 0: To check if Pdftk is already installed

sudo apt list | grep pdftk 

If output contains '[installed]' tag with pdftk then you can skip step1 i.e if the output is like this

pdftk/xenial 2.02-4 amd64 [installed]

Step 1: Install pdftk

sudo apt-get install pdftk

Step 2: Run following command

pdftk /path/to/input.pdf input_pw <yourpassword> output out.pdf

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If you don't want to install pdftk there is another utility qpdf which is automatically installed (at least on 16.04 which I am using)

To use qpdf for generating unsecured pdf run following command.

qpdf -password=<your-password> -decrypt /path/to/secured.pdf out.pdf

For detailed information take a look at this HTG tutorial

Answer 2

I tried this in ubuntu mate 19.04:

sudo apt-get install qpdf
qpdf --password=YOURPASSWORD-HERE --decrypt input.pdf output.pdf

Source

EDITED: You can also open the file in chrome first and then save as PDF.

Answer 3

This is an old question, but seems to be a reference on the matter and, surprisingly, none of the answers tells us how to avoid passing the password on the command line (which may be a source of leakage). Of course, since this is about removing the password protection from the file, maybe you don't care. But maybe you received a pdf from a company which used some data of yours to encrypt the file, and you'd like to avoid leaking it.

With pdftk we can use:

pdftk protected.pdf input_pw output out.pdf do_ask

The password is then queried in the terminal and you can type it.

With qpdf it is a little less direct. qpdf can read a password from stdin passing - to the --password-file= option:

qpdf --password-file=- --decrypt protected.pdf out.pdf

Once you enter that, qpdf will be waiting for input from stdin. You can then type <yourpassword>, RET and Ctrl+d (Ctrl+d sends EOF in Linux. In Windows, I think it would be Ctrl+z, but I'm not sure).

If you have an older version of qpdf (prior to v10.2.0), --password-file= didn't work this way, but one could still read a whole argument from stdin with the @- option. That given, you can use:

qpdf @- --decrypt protected.pdf out.pdf

Then type --password=<yourpassword>, RET and Ctrl+d.

Answer 4

sudo apt-get install pdftk
pdftk input.pdf output output.pdf user_pw YOURPASSWORD-HERE

This takes your input.pdf, removes the passwords and exports it as output.pdf.

You may want to take a look here to explore additional mehods.

Answer 5

Use this zsh function:

pdf-unencrypt () {
    : "Usage: <file>
Uses ghostscript to rewrite the file without encryption."
    local in="$1"
    gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile="${in:r}_unencrypted.pdf" -c .setpdfwrite -f "$in"
}

: is a no-operations function. $in:r gets the variable without its extension. You obviously need ghostscript installed.

Answer 6

if you don't have the password you can still unprotect the pdf document thanks to ghostscript :

gs -q -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=unencrypted.pdf -c .setpdfwrite -f my-protected-pdf-file.pdf

if you need to install GhostScript : How to install newer version of ghostscript on server than provided from ubuntu?

Answer 7

Rising the topic from the dead a little bit here (but I am a new Linux user, so...);

1. Anyhow, I also used the file for which I had known the password. But I used "Master PDF Editor 5" (unregistered, free version) to remove the password (File - Properties - Security - No Encription).
2. However, since "Master PDF Editor 5" leaves the watermark (which I personally, do not mind), I re-opened (the now unlocked file) in Libre Office Draw and removed the watermark.
3. I exported the file in PDF, which additionally resulted in tremendous compression without any losses. It was a very simple file; one sheet only, with text in the table, but the above process reduced the size from 70-ish KB to 22-ish KB.

Answer 8

If you already have a password, you can use the following to remove the password

gs -dNOPAUSE -dBATCH -q -sDEVICE=pdfwrite -sPDFPassword=password -sOutputFile=output2.pdf -f input.pdf

Answer 9

I think I might as well chime in with a little script I built around pdftk and gum.

#!/bin/bash
if [[ -z "$1" || ! -f  "$1" ]]; then
  echo "Select a file:"
  file="$(gum file)"
  echo -e "${file}\n"
else
  file="$1"
fi
pdftk "${file}" input_pw output "${file//.pdf/_decrypted.pdf}" do_ask

You can provide a file as the first parameter and the decrypted file will be saved with _decrypted.pdf postfix. If you don't provide a file name as the first parameter it will bring up gum's file chooser.