3 ms·

I kind of wish Git had a feature where multiple people could sign a PR or commit. Is there a multiple signature method that isn't "just" signing other people's

I kind of wish Git had a feature where multiple people could sign a PR or commit. Is there a multiple signature method that isn't "just" signing other people's signatures?

deleted 2y ago
[deleted]
jazzyjackson 2y ago
if you have a trusted central party you could reconstruct shards of a signing key, known as threshold cryptography eg Shamirs Secret Sharing
- treyd 2y ago
  You don't need a trusted central party. You can sign using just shamir shares with a multi-round MPC protocol without ever reconstructing the real key. There's round-optimized schemes like MuSig2 and FROST for specifically schnorr-based signatures, which GPG doesn't support but are used in other places. I don't know what the effort to integrate that into git would look like.
  - kreetx 2y ago
    If you're just signing, is there any role for MPC in in there?
    - treyd 2y ago
      To do the signing without having to reconstruct the privkey in any single location.
leni536 2y ago
I guess you could sign a git note[1] on an existing commit. As a bonus you could add metadata about what you are actually signing off, like "approved" or even "rejected". Just adding an additional signature on top of an existing commit wouldn't carry too much info. What are you actually signing off on? Is it approval? Is it acknowledgement? And then it can be hard to sign off on something negative, like a code review that rejects. [1] https://git-scm.com/docs/git-notes https://git-scm.com/docs/git-notes
remram 2y ago
You can sign tags, and you can make as many tags as you want. So for example you could have 'dev1-1.0' signed by dev1, 'dev2-1.0' signed by dev2, etc to have that revision signed by multiple developers.
k__ 2y ago
Yes. Threshold cryptography. Each participant generates one part of a key, and can only create one part of the signature. You can do stuff like requiring 3 of 5 signatures parts to be valid, etc.

I kind of wish Git had a feature where multiple people could sign a PR or commit. Is there a multiple signature method that isn't "just" signing other people's signatures?

deleted 2y ago

[deleted]

jazzyjackson 2y ago

if you have a trusted central party you could reconstruct shards of a signing key, known as threshold cryptography eg Shamirs Secret Sharing

treyd 2y ago
You don't need a trusted central party. You can sign using just shamir shares with a multi-round MPC protocol without ever reconstructing the real key. There's round-optimized schemes like MuSig2 and FROST for specifically schnorr-based signatures, which GPG doesn't support but are used in other places. I don't know what the effort to integrate that into git would look like.
- kreetx 2y ago
  If you're just signing, is there any role for MPC in in there?
  - treyd 2y ago
    To do the signing without having to reconstruct the privkey in any single location.

leni536 2y ago

I guess you could sign a git note[1] on an existing commit. As a bonus you could add metadata about what you are actually signing off, like "approved" or even "rejected". Just adding an additional signature on top of an existing commit wouldn't carry too much info. What are you actually signing off on? Is it approval? Is it acknowledgement? And then it can be hard to sign off on something negative, like a code review that rejects. [1] https://git-scm.com/docs/git-notes https://git-scm.com/docs/git-notes

remram 2y ago

You can sign tags, and you can make as many tags as you want. So for example you could have 'dev1-1.0' signed by dev1, 'dev2-1.0' signed by dev2, etc to have that revision signed by multiple developers.

k__ 2y ago

Yes. Threshold cryptography. Each participant generates one part of a key, and can only create one part of the signature. You can do stuff like requiring 3 of 5 signatures parts to be valid, etc.