openwall / openwall/john

HMAC formats supporting the other ordering of key and data

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#4,259 3 comments 0 reactions 0 assignees View on GitHub

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enhancement new format
Dominant language
C
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Description

HMAC is defined as operating on key and data, not on password and salt, and its direct uses for password hashing are actually misuses. The way we support cracking of HMAC-* in JtR is treating password as key and salt as data. This appeared to match the demand, but now we got a request to support the other ordering of key and data as well:

https://www.openwall.com/lists/john-users/2020/05/05/3

Incidentally, if #1903 is implemented it'd provide such support as a side-effect.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing the existing HMAC-* support and the openwall.com discussion linked in the issue. Inspect issue #1903 to understand the proposed related work and whether it covers the alternate key/data ordering. Done means John the Ripper supports the requested ordering in the relevant HMAC formats.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
cryptography, security
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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