Documentation/technical: describe signature formats

We use different types of signature formats in different places. Set up the infrastructure and overview to describe them systematically in our technical documentation. Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Michael J Gruber committed Jun 17, 2016 at 09:46 UTC 76f9d8bac8138d4c0caac02983ef4df7f9a51cba
2 files changed +18
Documentation/Makefile
+1
@@ -76,6 +76,7 @@ TECH_DOCS += technical/protocol-common
76 TECH_DOCS += technical/racy-git
77 TECH_DOCS += technical/send-pack-pipeline
78 TECH_DOCS += technical/shallow
79 +TECH_DOCS += technical/signature-format
80 TECH_DOCS += technical/trivial-merge
81 SP_ARTICLES += $(TECH_DOCS)
82 SP_ARTICLES += technical/api-index
Documentation/technical/signature-format.txt new
+17
@@ -0,0 +1,17 @@
1 +Git signature format
2 +====================
3 +
4 +== Overview
5 +
6 +Git uses cryptographic signatures in various places, currently objects (tags,
7 +commits, mergetags) and transactions (pushes). In every case, the command which
8 +is about to create an object or transaction determines a payload from that,
9 +calls gpg to obtain a detached signature for the payload (`gpg -bsa`) and
10 +embeds the signature into the object or transaction.
11 +
12 +Signatures always begin with `-----BEGIN PGP SIGNATURE-----`
13 +and end with `-----END PGP SIGNATURE-----`, unless gpg is told to
14 +produce RFC1991 signatures which use `MESSAGE` instead of `SIGNATURE`.
15 +
16 +The signed payload and the way the signature is embedded depends
17 +on the type of the object resp. transaction.