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Re: Is the sha256 object format experimental or not?

From
Junio C Hamano <gitster@pobox.com>
Date
May 13, 2021, 21:03 UTC
Message-ID
<xmqqo8de9wis.fsf@gitster.g>
In-Reply-To
<20210513202919.GE11882@localhost>
dwh@linuxprogrammer.org writes:
> I think Git should externalize the calculation of object digests just
> like it externalizes the calcualtion of object digital signatures.

The hashing algorithms used to generate object names has requirements fundamentally different from that of digital signatures. I strongly suspect that that fact would change the equation when you rethink what you said above.

We can "upgrade" digital signature algorithms fairly easily---nobody would complain if you suddenly choose different signing algorithm over a blob of data, as long as all project participants are aware (and self-describing datastream helps here) and are capable of grokking the new algorithm we are adopting. But because object names are used by one object to refer to another, and most importantly, we do not want a single object to have multiple names, we cannot afford to introduce a new hashing algorithm every time we feel like it. In other words, diversity of object naming algorithms is to be avoided as much as possible, while diversity of signature algorithms is naturally expected.

Previous: dwh@linuxprogrammer.orgNext: dwh@linuxprogrammer.org
Message 15 of 19 in “Preserving the ability to have both SHA1 and SHA256 signatures”
  1. dwh@linuxprogrammer.orgMay 8, 2021
  2. Christian CouderMay 8, 2021
  3. Junio C HamanoMay 8, 2021
  4. Felipe ContrerasMay 8, 2021
  5. Stefan MochMay 8, 2021
  6. Junio C HamanoMay 8, 2021
  7. brian m. carlsonMay 9, 2021
  8. Is the sha256 object format experimental or not?Ævar Arnfjörð Bjarmason, May 10, 2021
  9. brian m. carlsonMay 10, 2021
  10. dwh@linuxprogrammer.orgMay 13, 2021
  11. Konstantin RyabitsevMay 13, 2021
  12. dwh@linuxprogrammer.orgMay 13, 2021
  13. Konstantin RyabitsevMay 14, 2021
  14. dwh@linuxprogrammer.orgMay 14, 2021
  15. Junio C HamanoMay 13, 2021
  16. dwh@linuxprogrammer.orgMay 13, 2021
  17. Ævar Arnfjörð BjarmasonMay 14, 2021
  18. dwh@linuxprogrammer.orgMay 14, 2021
  19. Jonathan NiederMay 18, 2021

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