Steps to enable GPG signing of git commits.

gpg_git_signing.md

If anyone is interested in setting up their system to automatically (or manually) sign their git commits with their GPG key, here are the steps:

1. Generate and add your key to GitHub
2. $ git config --global commit.gpgsign true ([OPTIONAL] every commit will now be signed)
3. $ git config --global user.signingkey ABCDEF01 (where ABCDEF01 is the fingerprint of the key to use)
4. $ git config --global alias.logs "log --show-signature" (now available as $ git logs)
5. $ git config --global alias.cis "commit -S" (optional if global signing is false)
6. $ echo "Some content" >> example.txt
7. $ git add example.txt
8. $ git cis -m "This commit is signed by a GPG key." (regular commit will work if global signing is enabled)
9. $ git logs

IntelliJ IDEA Integration

If you perform git commits through IntelliJ and want them to be signed, add the following line to your ~/.gnupg/gpg.conf file:

# This option tells gpg not to expect a TTY interface and allows IntelliJ to sign commits
no-tty

Atlassian SourceTree Integration

If you perform git commits through SourceTree and want them to be signed, open Preferences > General and ensure that the GPG Program field has the value set to the directory containing the gpg2 executable, for example /usr/local/MacGPG2/bin. Even if your gpg executable is version 2, the gpg2 executable must be present.

Then click the Settings icon at the top right of a repository window, click the Security icon, and check "Enable GPG key signing for commits" and select the desired key. If you have a default-key setting in ~/.gnupg/gpg.conf, this should be correctly populated already.

Resources

• https://youtrack.jetbrains.com/issue/IDEA-110261#comment=27-1388832
• https://github.com/blog/2144-gpg-signature-verification
• https://help.github.com/articles/signing-commits-using-gpg/
• https://unix.stackexchange.com/questions/48862/how-can-i-create-an-alias-for-a-git-action-command-which-includes-spaces
• https://mikegerwitz.com/papers/git-horror-story
• https://blog.erincall.com/p/signing-your-git-commits-with-gpg

Found another issue with sourcetree:

git -c diff.mnemonicprefix=false -c core.quotepath=false -c credential.helper=sourcetree \
    -c "gpg.program=/Applications/SourceTree\ (1.8.1).app/Contents/Resources/bin/stgpg.sh" commit \
    -q --no-verify --gpg-sign=9B192B5379B13B73 \
    -F /var/folders/bl/hw7sxsj97vjdqvtjqn1707wh0000gr/T/SourceTreeTemp.fsKguB 
error: cannot run /Applications/SourceTree\ (1.8.1).app/Contents/Resources/bin/stgpg.sh: No such file or directory
error: could not run gpg.
fatal: failed to write commit object
Completed with errors, see above

The path is malformed:
-c "gpg.program=/Applications/SourceTree\ (1.8.1).app/Contents/Resources/bin/stgpg.sh"

it should be without the escape since it is inside double quotes:
-c "gpg.program=/Applications/SourceTree (1.8.1).app/Contents/Resources/bin/stgpg.sh"

Notice the extra escape symbols! Not sure where to fix this :(
No wait, found out where to fix it:

$ git config --list | grep gpg
commit.gpgsign=true
gpg.program=/Applications/SourceTree (1.8.1).app/Contents/Resources/bin/stgpg.sh

Tried various things but they all failed it with:

git config --global gpg.program "/Applications/SourceTree\ \(1.8.1\).app/Contents/Resources/bin/stgpg.sh"
git config --global gpg.program "/Applications/SourceTree (1.8.1).app/Contents/Resources/bin/stgpg.sh"

i. then shutdown sourcetree
ii. then restarted it from the terminal in which above fix was made in order for it to be loaded into the sourcetree env
iii. and tried my commits again, no luck :(

What i need to happen is for sourcetree to NOT put the extra escape so I ran it from cmd-line but it sortof defeats the purpose of using sourcetree :(

git -c diff.mnemonicprefix=false -c core.quotepath=false -c credential.helper=sourcetree \
-c "gpg.program=/Applications/SourceTree (1.8.1).app/Contents/Resources/bin/stgpg.sh" commit \
q --no-verify --gpg-sign=9B192B5379B13B73 \
-F /var/folders/bl/hw7sxsj97vjdqvtjqn1707wh0000gr/T/SourceTreeTemp.XrZtn7 

worked.

Don't forget to hit the sign commit button under commit options when going to commit or tag on SourceTree.

Thanks for this!

Dont forget to restart the gpg-agent so the changes to ~/.gnupg/gpg.conf will take affect. The agent will start next time it is needed.
gpgconf --kill gpg-agent

Wondering if you have an example of commit via API to avoid the
"verification": {
"verified": false,
"reason": "unsigned",
"signature": null,
"payload": null
}
}

example via curl (-S does not seems to work)
git config --global commit.gpgsign true
git config --global user.signingkey ABCDEF01
curl --silent -u (user):(secret) -S -X PUT "https://api.github.com/repos//GPG_commit_test/contents/P3.txt" -d '{ "branch":"master","message":"1234 -Test","author": {"name": "(github id)","email": "email@whatever.com"},"content":"VGVzdCBUZXN0" }'