openwall / openwall/john

Specialize SIMD SHA-256 for half-length input, iterated hashing

Open
#5,426 2 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

enhancement
Dominant language
C
Stars
13.6k
Forks
2.6k
PR merge metrics
No merged PRs in 30d

Description

Implement changes to SIMD SHA-256 and to some formats that use it, similarly to what #5425 did for SHA-512.

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 comparing this issue with #5425, then locate the SIMD SHA-256 implementation and the formats that use iterated hashing. Determine which half-length input paths and tests are affected; done means the specialized behavior matches the SHA-512 precedent without breaking those formats.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
cryptography, performance
Issue type
Feature
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
20/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.