only algorithm code 1 and 2 are supported

Question

I would like to read the pdf file. This is a book.pdf with a password (256 bit AES encryption). I know a password. I am using Jupyter Notebook.

I get an error:

import PyPDF2
reader = PyPDF2.PdfFileReader('book.pdf')
reader.decrypt('333')
reader.getPage(0)


---------------------------------------------------------------------------
 NotImplementedError                       Traceback (most recent call last)
 <ipython-input-12-7dd54b6a760a> in <module>()
  1 import PyPDF2
  2 reader = PyPDF2.PdfFileReader('book.pdf')
  ----> 3 reader.decrypt('333')
  4 reader.getPage(0)

 c:\users\a\programs\python\python36-32\lib\site-packages\PyPDF2\pdf.py in 
 decrypt(self, password)
 1985         self._override_encryption = True
 1986         try:
 -> 1987             return self._decrypt(password)
 1988         finally:
 1989             self._override_encryption = False

 c:\users\a\python\python36-32\lib\site-packages\PyPDF2\pdf.py in 
_decrypt(self, password)
1994             raise NotImplementedError("only Standard PDF encryption 
handler is available")
1995         if not (encrypt['/V'] in (1, 2)):
-> 1996             raise NotImplementedError("only algorithm code 1 and 2 
are supported")
1997         user_password, key = self._authenticateUserPassword(password)
1998         if user_password:

NotImplementedError: only algorithm code 1 and 2 are supported

Also see https://github.com/mstamy2/PyPDF2/issues/385 for status. Basically, PyPDF2 has been dead for 3 years; after half a year of discussion on resuming maintenance, it looks like the people involved have decided to abandon it and begin work on a [PyPDF3](https://github.com/mstamy2/PyPDF3) project, but little to nothing has been done on that yet. So, the answer is either (a) wait until PyPDF3 is ready for prime time (if ever), (b) switch to a different PDF library, or (c) use workarounds like subprocessing out to command-line tools for steps PyPDF2 can't handle, like decrypting algorithm 4. — abarnert, Jun 07 '18 at 23:12

Roshin Raphel · Answer 1 · 2020-08-26T06:47:05.023

7

Recently, I also faced the same issue. I am not sure why the error occurs, but here is a way to mitigate it, using a different module than PyPDF2 :

import pikepdf
pdf = pikepdf.open('book.pdf',password='333')
pdf.save('book_without_pass.pdf')

The above code save the encrypted pdf book.pdf with the password, '333' to book_without_pass.pdf

edited Aug 26 '20 at 06:47

answered Aug 21 '20 at 15:44

Roshin Raphel

2,612
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3

Also works for files that give this error, even though they are not password-protected. – Jelmer Wind Jan 25 '21 at 12:55
Can it access the contents of `pdf` without having to first save it? I cant seem to be able to – West Mar 22 '22 at 12:36

score 1 · Answer 2 · answered Dec 24 '20 at 15:07

1

I had the same issue, then changed PDF options on Encryption Level: 40 bit RC4 and it helped. I think it relates with PyPDF2 module.

answered Dec 24 '20 at 15:07

Dmitrii P.

11
1

score 1 · Answer 3 · edited Jul 08 '21 at 22:02

1

NotImplementedError This is because module does not support the files encrypted format
You have to try different modules

edited Jul 08 '21 at 22:02

Sven Eberth

3,057
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answered Jul 07 '21 at 16:07

Shrikant Sawarkar

15
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score 1 · Answer 4 · answered Mar 27 '23 at 17:04

Meanwhile, the necessary functionality has been added in PyPDF2.

I tested it in version 3.0.1. If you arrived here via a search on the error message, you should check whether the latest PyPDF2 version fixes your problem.

For historical background, see the comment that abarnert posted under the question.

only algorithm code 1 and 2 are supported

4 Answers4