this post was submitted on 21 Jan 2024
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Privacy
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Zip uses very bad encryption that is vulnerable to a known plaintext attack. Do not ever use PKZIP encryption for any purpose https://github.com/kimci86/bkcrack
They added AES encryption to the spec 20 years ago. It's pretty-well supported AFAIK.
Yeah zips have no mechanism to prevent brute forcing as far as I'm aware. You can attempt as many passwords as you want as frequently as you want without any sort of rate limit.
That’s not the issue. You can attempt as many passwords as you want in actually secure password managers as well. KeepassXC for instance IS secure, you can still brute force the password, but because of the hashing algorithm they use it’s extremely hard. With PKZIP if you know some of the words in the file, you can easily guess the password in just a few hours because the encryption algorithm it uses isn’t secure
Both are true. Brute forcing zips is also faster than brute forcing almost anything else. Other formats use key derivation functions like PBKDF2-SHA1 (hundreds of thousands of iterations of sha1) to slow down the calculation of the key from the password, but PKZIP does not do this. Brute forcing zips can be done at 10 billion passwords per second on a typical GPU, whereas rar/7z/keepass are only a few thousand per second.
Here's an interesting research paper describing both the known plaintext attack and the standard brute force attack https://www.scitepress.org/Papers/2019/73605/73605.pdf
Oh interesting, thanks for the clarification
I used to get some documents sent in a password encrypted zip file, they regularly messed up the password, so i ended up just brute forcing them when i received them since it was easier and faster (usually like 15 seconds)
Not very relevant here since i knew roughly the length of the password and it was quite short, but i thought it was pretty funny