| Git signature format |
| ==================== |
| |
| == Overview |
| |
| 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 gpg to obtain a detached signature for the payload (`gpg -bsa`) and |
| embeds the signature into the object or transaction. |
| |
| Signatures always begin with `-----BEGIN PGP SIGNATURE-----` |
| and end with `-----END PGP SIGNATURE-----`, unless gpg is told to |
| produce RFC1991 signatures which use `MESSAGE` instead of `SIGNATURE`. |
| |
| The signed payload and the way the signature is embedded depends |
| on the type of the object resp. transaction. |
| |
| == Tag signatures |
| |
| - created by: `git tag -s` |
| - payload: annotated tag object |
| - embedding: append the signature to the unsigned tag object |
| - example: tag `signedtag` with subject `signed tag` |
| |
| ---- |
| 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----- |
| ---- |
| |
| - verify with: `git verify-tag [-v]` or `git tag -v` |
| |
| ---- |
| 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 |
| ---- |
| |
| == Commit signatures |
| |
| - created by: `git commit -S` |
| - payload: commit object |
| - embedding: header entry `gpgsig` |
| (content is preceded by a space) |
| - example: commit with subject `signed commit` |
| |
| ---- |
| 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 |
| ---- |
| |
| - verify with: `git verify-commit [-v]` (or `git show --show-signature`) |
| |
| ---- |
| 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 |
| ---- |
| |
| == Mergetag signatures |
| |
| - created by: `git merge` on signed tag |
| - payload/embedding: the whole signed tag object is embedded into |
| the (merge) commit object as header entry `mergetag` |
| - example: merge of the signed tag `signedtag` as above |
| |
| ---- |
| 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 |
| ---- |
| |
| - verify with: verification is embedded in merge commit message by default, |
| alternatively with `git show --show-signature`: |
| |
| ---- |
| 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 |
| ---- |
