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Commit signing in 2023 is kinda wack

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Re: Commit signing in 2023 is kinda wack

#11

Post by DaSHacka »

olalonde wrote: post #8
DaSHacka wrote: post #7

Earlier quoted context omitted.

How is this any different from just using a Yubikey? I fail to see how cryptocurrencies are in any way unique in this regard.

I don't know, I've never used one. Can keys stored on a Yubikey be restored from a 24 word seed + passphrase? Do Yubikeys self-destroy after 3 incorrect PINs?

No, but that's the whole point. One less avenue for exploitation. You would have to physically destroy the device, and find an exploit in the smartcard on the chip itself to obtain the private keys.

Re: Commit signing in 2023 is kinda wack

#12

Post by olalonde »

DaSHacka wrote: post #11
olalonde wrote: post #8

Earlier quoted context omitted.

I don't know, I've never used one. Can keys stored on a Yubikey be restored from a 24 word seed + passphrase? Do Yubikeys self-destroy after 3 incorrect PINs?

No, but that's the whole point. One less avenue for exploitation. You would have to physically destroy the device, and find an exploit in the smartcard on the chip itself to obtain the private keys.

Then it doesn't solve the "key loss happens" problem. You lose/break/damage your device and your keys are gone.

Re: Commit signing in 2023 is kinda wack

#13

Post by leni536 »

the_mitsuhiko wrote: post #5

Not as the creator intended, but Commit signing on GitHub is mostly an automatic thing at this point if you use pull requests and squash merges. The commits on the PR itself are unsigned, but the merge to the branch is attested and marked as signed by GitHub itself. Since you need to have permission at the time of merge, it's a rather trustworthy indication. Here an example from Sentry's master which other than bot t…

I fail to so what security you gain by trusting Github's key.

Re: Commit signing in 2023 is kinda wack

#14

Post by DaSHacka »

olalonde wrote: post #12
DaSHacka wrote: post #11

Earlier quoted context omitted.

No, but that's the whole point. One less avenue for exploitation. You would have to physically destroy the device, and find an exploit in the smartcard on the chip itself to obtain the private keys.

Then it doesn't solve the "key loss happens" problem. You lose/break/damage your device and your keys are gone.

You're supposed to register more than one key, and leave the other on standby.

A common practice is one Yubikey on your keyring, another left at home (optionally left in your Desktop or a computer that doesn't leave the house)

Re: Commit signing in 2023 is kinda wack

#15

Post by captn3m0 »

olalonde wrote: post #6
Jean-Papoulos wrote: post #4

Earlier quoted context omitted.

This is absolutely not solving the problem, it's at best kicking it down the road and doesn't solve the key getting compromised or identity changing.

Can you be more specific about how it is absolutely not solving the problem? To compromise a key you need to find a hidden piece of paper or engraved plate that your target has physically hidden somewhere. Plus guess a secret password (before your target has noticed you got to their seed and rang the alarm). Almost impossible to pull off. I'm not sure what you mean about identity changing. If you mean a sex change or…

Any knowledge held by a person is retrievable with a $5 wrench. Things can get stolen, houses can burn down, bank lockers can be robbed.

Identity Changes, such as name changes, are relevant in the Web o Trust/GPG world where you typically require a valid ID proof (such as a passport) and physical presence before you sign someone's keys at a Key Signing Party.

Re: Commit signing in 2023 is kinda wack

#16

Post by the_mitsuhiko »

leni536 wrote: post #13
the_mitsuhiko wrote: post #5

Not as the creator intended, but Commit signing on GitHub is mostly an automatic thing at this point if you use pull requests and squash merges. The commits on the PR itself are unsigned, but the merge to the branch is attested and marked as signed by GitHub itself. Since you need to have permission at the time of merge, it's a rather trustworthy indication. Here an example from Sentry's master which other than bot t…

I fail to so what security you gain by trusting Github's key.

You get an attestation that the person that merged corresponds to a particular github identity. More importantly you know that at the time the person merged the commit they had a 2FA token that was valid. The only way the commit could have been forged is that at the time it took place, the user account itself was compromised.

Re: Commit signing in 2023 is kinda wack

#17

Post by olalonde »

captn3m0 wrote: post #15
olalonde wrote: post #6

Earlier quoted context omitted.

Can you be more specific about how it is absolutely not solving the problem? To compromise a key you need to find a hidden piece of paper or engraved plate that your target has physically hidden somewhere. Plus guess a secret password (before your target has noticed you got to their seed and rang the alarm). Almost impossible to pull off. I'm not sure what you mean about identity changing. If you mean a sex change or…

Any knowledge held by a person is retrievable with a $5 wrench. Things can get stolen, houses can burn down, bank lockers can be robbed. Identity Changes, such as name changes, are relevant in the Web o Trust/GPG world where you typically require a valid ID proof (such as a passport) and physical presence before you sign someone's keys at a Key Signing Party.

Fire issue is solved with multiple backups or titanium engraving. Theft is solved with secret passphrase that is either memorized or stored in a separate location. The $5 wrench attack (aka kidnapping and torture) is unsolved but it is extremely rare in comparison to the much more common key leaks/theft scenario. And I don't believe any defense is really possible against that one, cryptographically or otherwise.

> Identity Changes, such as name changes, are relevant in the Web o Trust/GPG world where you typically require a valid ID proof (such as a passport) and physical presence before you sign someone's keys at a Key Signing Party.

It doesn't solve that problem but I don't think "real life" identity is really relevant for the purpose of contributing code. In fact, plenty of open source contributors are pseudonymous.

Re: Commit signing in 2023 is kinda wack

#18

Post by captn3m0 »

the_mitsuhiko wrote: post #16
leni536 wrote: post #13

Earlier quoted context omitted.

I fail to so what security you gain by trusting Github's key.

You get an attestation that the person that merged corresponds to a particular github identity. More importantly you know that at the time the person merged the commit they had a 2FA token that was valid. The only way the commit could have been forged is that at the time it took place, the user account itself was compromised.

GitHub uses fairly long-lived sessions. "sudo mode"[0] on GitHub, where it asks for a verification of the 2FA is only for sensitive actions, which PR merges are not. So a cookie-stealing attack can easily merge PRs for quite a while.

And 2FA isn't a requirement for a PR merge afaik, Except via org-wide enforcement? So the guarantee is lower - the commit was merged with a valid session token.

[0]: https://docs.github.com/en/authentication/keeping-your-accou...

Re: Commit signing in 2023 is kinda wack

#19

Post by the_mitsuhiko »

captn3m0 wrote: post #18
the_mitsuhiko wrote: post #16

Earlier quoted context omitted.

You get an attestation that the person that merged corresponds to a particular github identity. More importantly you know that at the time the person merged the commit they had a 2FA token that was valid. The only way the commit could have been forged is that at the time it took place, the user account itself was compromised.

GitHub uses fairly long-lived sessions. "sudo mode"[0] on GitHub, where it asks for a verification of the 2FA is only for sensitive actions, which PR merges are not. So a cookie-stealing attack can easily merge PRs for quite a while. And 2FA isn't a requirement for a PR merge afaik, Except via org-wide enforcement? So the guarantee is lower - the commit was merged with a valid session token. [0]: https://docs.github.…

If you enforce an organization to have a 2FA sign-in then yes, it's enforced that the session was created with a second factor. In Sentry's case you also need to go through SSO once every 24 hours. There is no way for you to get a valid session token without going through that which can be used to create a signed merge commit.

Re: Commit signing in 2023 is kinda wack

#20

Post by alfiedotwtf »

olalonde wrote: post #17
captn3m0 wrote: post #15

Earlier quoted context omitted.

Any knowledge held by a person is retrievable with a $5 wrench. Things can get stolen, houses can burn down, bank lockers can be robbed. Identity Changes, such as name changes, are relevant in the Web o Trust/GPG world where you typically require a valid ID proof (such as a passport) and physical presence before you sign someone's keys at a Key Signing Party.

Fire issue is solved with multiple backups or titanium engraving. Theft is solved with secret passphrase that is either memorized or stored in a separate location. The $5 wrench attack (aka kidnapping and torture) is unsolved but it is extremely rare in comparison to the much more common key leaks/theft scenario. And I don't believe any defense is really possible against that one, cryptographically or otherwise. > Id…

It’s kind of a solved problem too, Julian Assange even worked on a file system called Rubberhose - https://en.m.wikipedia.org/wiki/Deniable_encryption
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