BUG: Encrypt / decrypt Stream object dictionaries

[pilotandy]

Fixes #2227

[exiledkingcc]

this pr can fix #2227 with no doubt.

[pubpub-zz]

@stefan6419846
thanks for your analysis

@pilotandy
here is a way to get your test working without calling the to induce the error:

def test_encrypt_stream_dictionary(pdf_file_path):
    user_password = secrets.token_urlsafe(10)

    reader = PdfReader(RESOURCE_ROOT / "cmyk_image.pdf")
    page = reader.pages[0]
    original_image_obj = page["/Resources"]["/XObject"]["/I"]

    writer = PdfWriter()
    writer.add_page(reader.pages[0])
    writer.encrypt(
       user_pass
word=user_password,
       owner_password=None,
       algorithm="RC4-128",
    )
    with open(pdf_file_path, "wb") as output_stream:
        writer.write(output_stream)

    reader = PdfReader(pdf_file_path)
    assert reader.is_encrypted
    assert reader.decrypt(user_password) == PasswordType.OWNER_PASSWORD
    page = reader.pages[0]
    decrypted_image_obj = page["/Resources"]["/XObject"]["/I"]
    assert decrypted_image_obj["/ColorSpace"][3] == original_image_obj["/ColorSpace"][3]

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (ba9491c) 94.36% compared to head (6819b7b) 94.40%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2228      +/-   ##
==========================================
+ Coverage   94.36%   94.40%   +0.04%     
==========================================
  Files          43       43              
  Lines        7591     7595       +4     
  Branches     1497     1499       +2     
==========================================
+ Hits         7163     7170       +7     
+ Misses        264      262       -2     
+ Partials      164      163       -1     

Files	Coverage Δ
pypdf/_encryption.py	96.65% <100.00%> (+0.81%)	⬆️

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[MartinThoma]

(I've moved/removed a couple of comments from this discussion, as it was not primarily about the PR)

[MartinThoma]

@pilotandy May I move the PDF to https://github.com/py-pdf/sample-files (docs)?

I typically want files to be in the sample-files for two reasons:

1. pypdf repository size: I want to make sure that it is super easy to get pypdf. That includes that the git repository file size should not get too big.
2. sample-files can be used for other projects easily. I hope that the sample-files repository might get used by other PDF libraries and that we create a good re-usable set of test cases

[pilotandy]

@MartinThoma Here's the PR py-pdf/sample-files#25 for the sample files

[MartinThoma]

Thank you @pilotandy !

If you want,I can add you to https://pypdf.readthedocs.io/en/latest/meta/CONTRIBUTORS.html :-)

[pilotandy]

You're welcome! PyPDF is awesome! Sorry I'm not too good with github yet :/ You can add me to the contributors list. Just link it to my github. Craner, Andy

…

On Sat, Oct 7, 2023 at 2:36 AM Martin Thoma ***@***.***> wrote: Thank you @pilotandy <https://github.com/pilotandy> ! If you want,I can add you to https://pypdf.readthedocs.io/en/latest/meta/CONTRIBUTORS.html :-) — Reply to this email directly, view it on GitHub <#2228 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACNNKX6L5D6S4OPARBHBKN3X6EIBBAVCNFSM6AAAAAA5M77VF2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTONJRGY2TCOBUGI> . You are receiving this because you were mentioned.Message ID: ***@***.***>