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I have a Zip archive containing a single password-protected file file.txt. The encryption is "ZIP 2.0 Default Encryption" (ZipCrypto).

I know what kind of text (sentences) the "file.txt" contains.

  • Is it possible to use known-plaintext in that case? Or,
  • Do I need exactly a second known encrypted file to use this type of attack?
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  • $\begingroup$ This might help crypto.stackexchange.com/questions/3791/… $\endgroup$
    – Sango
    Oct 7 '19 at 12:47
  • $\begingroup$ I've closed this as a dupe since the answer to the other question includes the required resources saying that a plaintext attack is indeed possible, even if the question isn't directly about plaintext attack... $\endgroup$
    – Maarten Bodewes
    Oct 7 '19 at 16:59