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Extract files encrypted with PKWare AES encryption

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp
Domain
backend, security

Research direction

Start by tracing how SharpZipLib opens a ZIP entry and initializes decryption streams, then compare the entry flags and PKWare AES format with the existing encryption handling. Done means PKWare AES-encrypted entries can be extracted while unsupported encryption schemes remain unchanged; the issue does not name specific files or tests.

Written by the indexing model from the issue text.

Description

*no response* enhancement
Is your feature request related to a problem? Please describe.

We have a spec ambiguity with a third party spec; it says file in zip file to be encrypted with AES encryption.

There are two different versions of AES encryption; WinZip's version and PKWare's version. Almost everybody uses WinZip's version but this one vendor decided to use PKWare's version for reasons that we probably will never know.

So, we don't need to write these; but we do need to read them.

Describe the solution you'd like

Recognize the flags and initialize the AES decryption stream when opening such a zip entry.

No need to implement the other encryption schemes as far as we are concerned.

Describe alternatives you've considered

Looking for a commercial package as been considered.

Tags

No response

Additional context

No response

Dominant language
C#
Stars
3.9k
Forks
1k
PR merge metrics
No merged PRs in 30d

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