Re: [PATCH 3/9] docs: reflect actual double signature for tags
- From
brian m. carlson <sandals@crustytoothpaste.net>
- Date
- Sep 20, 2025, 15:29 UTC
- Message-ID
- <aM7IQibwwKFJZcYE@fruit.crustytoothpaste.net>
- In-Reply-To
- <xmqq348i138l.fsf@gitster.g>
On 2025-09-19 at 22:34:02, Junio C Hamano wrote:
Show 14 quoted lines
> "brian m. carlson" <sandals@crustytoothpaste.net> writes: > > > Signed Tags > > ~~~~~~~~~~~ > > +We add new fields "gpgsig" and "gpgsig-sha256" to the tag object format to > > +allow signing tags in both formats. The in-body signature is used for the > > +signature in the current hash algorithm and the header is used for the > > +signature in the other algorithm. Thus, a dual-signature tag will contain both > > Not suggesting a change in the text, but to make sure I am reading > the new text correctly. Does "the other algorithm" refer to the > compatibility hash algorithm specified by the compatObjectFormat > extension and the "current" algorithm refers to the objectFormat > extension?
The "current algorithm" is usually the main algorithm (that is, SHA-256 where `extensions.objectformat` is `sha256`) and the "other algorithm" is the compatibility algorithm (SHA-1 in that case). However, when you convert that object to SHA-1 to hash it in SHA-1, the "current algorithm" becomes SHA-1 and the "other algorithm" is SHA-256.
Does that make sense?
Show 10 quoted lines
> > +an in-body signature and a gpgsig-sha256 header for the SHA-1 format of an > > +object or both an in-body signature and a gpgsig header for the SHA-256 format > > +of and object. > > > > -This means tags can be signed > > +The signed payload of the tag is the content of the tag in the current > > +algorithm with both its gpgsig and gpgsig-sha256 fields and > > My reading of the previous paragraph is that we cannot have gpgsig > and gpgsig-sha256 fields on a single object at the same time.
Correct, unless we come up with a third hash algorithm. Hopefully that is a long way away, and we are not considering that case here.
Show 10 quoted lines
> Should we say "gpgsig or gpgsig-sha256" (instead of "and"), to get > the resulting text parsable as: > > both > its gpgsig or gpgsig-sha256 fields > and > "-----BEGIN PGP SIGNATURE-----" delimited in-body signature > removed. > > instead?
Sure, I'll include that in a reroll.
-- brian m. carlson (they/them) Toronto, Ontario, CA