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<h1>gitformat-signature</h1> <h2 id="_name">Name</h2> <div class="sectionbody"> <p>gitformat-signature - Git cryptographic signature formats</p> </div> <h2 id="_synopsis">Synopsis</h2> <div class="sectionbody"> <div class="verseblock"> <pre class="content"><[tag|commit] object header(s)>
<over-the-wire protocol></pre> </div> </div> <h2 id="_description">Description</h2> <div class="sectionbody"> <p>Git uses cryptographic signatures in various places, currently objects (tags, commits, mergetags) and transactions (pushes). In every case, the command which is about to create an object or transaction determines a payload from that, calls an external program to obtain a detached signature for the payload (<code>gpg -bsa</code> in the case of PGP signatures), and embeds the signature into the object or transaction.</p> <p>Signatures begin with an "ASCII Armor" header line and end with a tail line, which differ depending on signature type (as selected by <code>gpg.format</code>, see <a href="git-config">git-config[1]</a>). These are, for <code>gpg.format</code> values:</p> <div class="dlist"> <dl> <dt class="hdlist1" id="Documentation/gitformat-signature.txt-codegpgcodePGP"> <code>gpg</code> (PGP) </dt> <dd> <p><code>-----BEGIN PGP SIGNATURE-----</code> and <code>-----END PGP SIGNATURE-----</code>. Or, if gpg is told to produce RFC1991 signatures, <code>-----BEGIN PGP MESSAGE-----</code> and <code>-----END PGP MESSAGE-----</code></p> </dd> <dt class="hdlist1" id="Documentation/gitformat-signature.txt-codesshcodeSSH"> <code>ssh</code> (SSH) </dt> <dd> <p><code>-----BEGIN SSH SIGNATURE-----</code> and <code>-----END SSH SIGNATURE-----</code></p> </dd> <dt class="hdlist1" id="Documentation/gitformat-signature.txt-codex509codeX509"> <code>x509</code> (X.509) </dt> <dd> <p><code>-----BEGIN SIGNED MESSAGE-----</code> and <code>-----END SIGNED MESSAGE-----</code></p> </dd> </dl> </div> <p>Signatures sometimes appear as a part of the normal payload (e.g. a signed tag has the signature block appended after the payload that the signature applies to), and sometimes appear in the value of an object header (e.g. a merge commit that merged a signed tag would have the entire tag contents on its "mergetag" header). In the case of the latter, the usual multi-line formatting rule for object headers applies. I.e. the second and subsequent lines are prefixed with a SP to signal that the line is continued from the previous line.</p> <p>This is even true for an originally empty line. In the following examples, the end of line that ends with a whitespace letter is highlighted with a <code>$</code> sign; if you are trying to recreate these example by hand, do not cut and paste them—they are there primarily to highlight extra whitespace at the end of some lines.</p> <p>The signed payload and the way the signature is embedded depends on the type of the object resp. transaction.</p> </div> <h2 id="_tag_signatures">Tag signatures</h2> <div class="sectionbody"> <div class="ulist"> <ul> <li> <p>created by: <code>git tag -s</code></p> </li> <li> <p>payload: annotated tag object</p> </li> <li> <p>embedding: append the signature to the unsigned tag object</p> </li> <li> <p>example: tag <code>signedtag</code> with subject <code>signed tag</code></p> </li> </ul> </div> <div class="listingblock"> <div class="content"> <pre>object 04b871796dc0420f8e7561a895b52484b701d51a
type commit
tag signedtag
tagger C O Mitter <committer@example.com> 1465981006 +0000
signed tag
signed tag message body
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQEcBAABAgAGBQJXYRhOAAoJEGEJLoW3InGJklkIAIcnhL7RwEb/+QeX9enkXhxn
rxfdqrvWd1K80sl2TOt8Bg/NYwrUBw/RWJ+sg/hhHp4WtvE1HDGHlkEz3y11Lkuh
8tSxS3qKTxXUGozyPGuE90sJfExhZlW4knIQ1wt/yWqM+33E9pN4hzPqLwyrdods
q8FWEqPPUbSJXoMbRPw04S5jrLtZSsUWbRYjmJCHzlhSfFWW4eFd37uquIaLUBS0
rkC3Jrx7420jkIpgFcTI2s60uhSQLzgcCwdA2ukSYIRnjg/zDkj8+3h/GaROJ72x
lZyI6HWixKJkWw8lE9aAOD9TmTW9sFJwcVAzmAuFX2kUreDUKMZduGcoRYGpD7E=
=jpXa
-----END PGP SIGNATURE-----</pre> </div> </div> <div class="ulist"> <ul> <li> <p>verify with: <code>git verify-tag [-v]</code> or <code>git tag -v</code></p> </li> </ul> </div> <div class="listingblock"> <div class="content"> <pre>gpg: Signature made Wed Jun 15 10:56:46 2016 CEST using RSA key ID B7227189
gpg: Good signature from "Eris Discordia <discord@example.net>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA 29A4 6109 2E85 B722 7189
object 04b871796dc0420f8e7561a895b52484b701d51a
type commit
tag signedtag
tagger C O Mitter <committer@example.com> 1465981006 +0000
signed tag
signed tag message body</pre> </div> </div> </div> <h2 id="_commit_signatures">Commit signatures</h2> <div class="sectionbody"> <div class="ulist"> <ul> <li> <p>created by: <code>git commit -S</code></p> </li> <li> <p>payload: commit object</p> </li> <li> <p>embedding: header entry <code>gpgsig</code> (content is preceded by a space)</p> </li> <li> <p>example: commit with subject <code>signed commit</code></p> </li> </ul> </div> <div class="listingblock"> <div class="content"> <pre>tree eebfed94e75e7760540d1485c740902590a00332
parent 04b871796dc0420f8e7561a895b52484b701d51a
author A U Thor <author@example.com> 1465981137 +0000
committer C O Mitter <committer@example.com> 1465981137 +0000
gpgsig -----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
$
iQEcBAABAgAGBQJXYRjRAAoJEGEJLoW3InGJ3IwIAIY4SA6GxY3BjL60YyvsJPh/
HRCJwH+w7wt3Yc/9/bW2F+gF72kdHOOs2jfv+OZhq0q4OAN6fvVSczISY/82LpS7
DVdMQj2/YcHDT4xrDNBnXnviDO9G7am/9OE77kEbXrp7QPxvhjkicHNwy2rEflAA
zn075rtEERDHr8nRYiDh8eVrefSO7D+bdQ7gv+7GsYMsd2auJWi1dHOSfTr9HIF4
HJhWXT9d2f8W+diRYXGh4X0wYiGg6na/soXc+vdtDYBzIxanRqjg8jCAeo1eOTk1
EdTwhcTZlI0x5pvJ3H0+4hA2jtldVtmPM4OTB0cTrEWBad7XV6YgiyuII73Ve3I=
=jKHM
-----END PGP SIGNATURE-----
signed commit
signed commit message body</pre> </div> </div> <div class="ulist"> <ul> <li> <p>verify with: <code>git verify-commit [-v]</code> (or <code>git show --show-signature</code>)</p> </li> </ul> </div> <div class="listingblock"> <div class="content"> <pre>gpg: Signature made Wed Jun 15 10:58:57 2016 CEST using RSA key ID B7227189
gpg: Good signature from "Eris Discordia <discord@example.net>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA 29A4 6109 2E85 B722 7189
tree eebfed94e75e7760540d1485c740902590a00332
parent 04b871796dc0420f8e7561a895b52484b701d51a
author A U Thor <author@example.com> 1465981137 +0000
committer C O Mitter <committer@example.com> 1465981137 +0000
signed commit
signed commit message body</pre> </div> </div> </div> <h2 id="_mergetag_signatures">Mergetag signatures</h2> <div class="sectionbody"> <div class="ulist"> <ul> <li> <p>created by: <code>git merge</code> on signed tag</p> </li> <li> <p>payload/embedding: the whole signed tag object is embedded into the (merge) commit object as header entry <code>mergetag</code></p> </li> <li> <p>example: merge of the signed tag <code>signedtag</code> as above</p> </li> </ul> </div> <div class="listingblock"> <div class="content"> <pre>tree c7b1cff039a93f3600a1d18b82d26688668c7dea
parent c33429be94b5f2d3ee9b0adad223f877f174b05d
parent 04b871796dc0420f8e7561a895b52484b701d51a
author A U Thor <author@example.com> 1465982009 +0000
committer C O Mitter <committer@example.com> 1465982009 +0000
mergetag object 04b871796dc0420f8e7561a895b52484b701d51a
type commit
tag signedtag
tagger C O Mitter <committer@example.com> 1465981006 +0000
$
signed tag
$
signed tag message body
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
$
iQEcBAABAgAGBQJXYRhOAAoJEGEJLoW3InGJklkIAIcnhL7RwEb/+QeX9enkXhxn
rxfdqrvWd1K80sl2TOt8Bg/NYwrUBw/RWJ+sg/hhHp4WtvE1HDGHlkEz3y11Lkuh
8tSxS3qKTxXUGozyPGuE90sJfExhZlW4knIQ1wt/yWqM+33E9pN4hzPqLwyrdods
q8FWEqPPUbSJXoMbRPw04S5jrLtZSsUWbRYjmJCHzlhSfFWW4eFd37uquIaLUBS0
rkC3Jrx7420jkIpgFcTI2s60uhSQLzgcCwdA2ukSYIRnjg/zDkj8+3h/GaROJ72x
lZyI6HWixKJkWw8lE9aAOD9TmTW9sFJwcVAzmAuFX2kUreDUKMZduGcoRYGpD7E=
=jpXa
-----END PGP SIGNATURE-----
Merge tag 'signedtag' into downstream
signed tag
signed tag message body
# gpg: Signature made Wed Jun 15 08:56:46 2016 UTC using RSA key ID B7227189
# gpg: Good signature from "Eris Discordia <discord@example.net>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA 29A4 6109 2E85 B722 7189</pre> </div> </div> <div class="ulist"> <ul> <li> <p>verify with: verification is embedded in merge commit message by default, alternatively with <code>git show --show-signature</code>:</p> </li> </ul> </div> <div class="listingblock"> <div class="content"> <pre>commit 9863f0c76ff78712b6800e199a46aa56afbcbd49
merged tag 'signedtag'
gpg: Signature made Wed Jun 15 10:56:46 2016 CEST using RSA key ID B7227189
gpg: Good signature from "Eris Discordia <discord@example.net>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA 29A4 6109 2E85 B722 7189
Merge: c33429b 04b8717
Author: A U Thor <author@example.com>
Date: Wed Jun 15 09:13:29 2016 +0000
Merge tag 'signedtag' into downstream
signed tag
signed tag message body
# gpg: Signature made Wed Jun 15 08:56:46 2016 UTC using RSA key ID B7227189
# gpg: Good signature from "Eris Discordia <discord@example.net>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg: There is no indication that the signature belongs to the owner.
# Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA 29A4 6109 2E85 B722 7189</pre> </div> </div> </div><div class="_attribution">
<p class="_attribution-p">
© 2012–2024 Scott Chacon and others<br>Licensed under the MIT License.<br>
<a href="https://git-scm.com/docs/gitformat-signature" class="_attribution-link">https://git-scm.com/docs/gitformat-signature</a>
</p>
</div>
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