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Git 3.0's upcoming SHA-256 default will be a costly mistake

570 points · 536 comments · chmaynard

  1. sigmar · · focus · HN ↗
    >it will be an incomprehensibly expensive and ultimately valueless and avoidable global nightmare.

    thought "costly" in the title and "incomprehensibly expensive" in the subheader meant this piece would discuss how much less performant sha-256 is on modern machines, but didn't see anything. isn't there hardware acceleration? how much worse is it?

    1. schacon · · focus · HN ↗
      Actually, I think sha-256 is possibly faster than the sha1dc variant that Git currently uses.

      I just sent a patch series to the list that enables sha1dc to be accelerated on modern CPU architectures to close to normal SHA1 speeds, but since it was ported from a Rust project by an agent, it will never be applied.

      <a href="https:&#x2F;&#x2F;lore.kernel.org&#x2F;git&#x2F;20260929112544.86511-1-scott@gitbutler.net&#x2F;" rel="nofollow">https:&#x2F;&#x2F;lore.kernel.org&#x2F;git&#x2F;20260929112544.86511-1-scott@git...

      1. xyzsparetimexyz · · focus · HN ↗

        [dead]

        1. ChrisRR · · focus · HN ↗
          What part of the code did you find bad when you reviewed it?
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