PBKDF2 formats: Support output dkLen other than multiples of native hash size (even shorter than it)
Open
Nobody has claimed this yet.
bug
enhancement
- Dominant language
- C
- Stars
- 13.6k
- Forks
- 2.6k
- PR merge metrics
- No merged PRs in 30d
Description
https://www.openwall.com/lists/john-users/2020/11/27/9
Since our current formats seem to be buggy (they accept such hashes but fails to crack them), this is fairly high prio.
I picture we could accept any length of input hash, down to say 48 bits. Should be trivial to implement.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the linked john-users discussion, then locate the PBKDF2 formats responsible for accepting hashes with non-multiple dkLen values. Check how these formats handle output lengths, including lengths shorter than the native hash size and down to 48 bits. Done means accepted hashes of those lengths crack correctly rather than only being parsed.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c
- Domain
- cryptography, security
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100