Git error - gpg failed to sign data

For troubleshooting, two things to first try:

• run git config --global gpg.program gpg2, to make sure git uses gpg2 and not gpg
• run echo "test" | gpg2 --clearsign, to make sure gpg2 itself is working

If that all looks all right, one next thing to try:

• run brew install pinentry to ensure you have a good tool installed for passphrase entry

If after that install, you re-try git commit and still get a "failed to sign the data" error, do:

• run gpgconf --kill gpg-agent to kill any running agent that might be hung

If that says gpgconf isn’t installed or doesn’t have a --kill option, you might try this:

1. cp ~/.gnupg ~/.gnupg-GOOD to save a copy of your ~/.gnupg to revert to later if needed
2. brew install gnupg21 to install GnuPG 2.1

The reason for saving a copy of your ~/.gnupg dir is, GnuPG 2.1 potentially creates/changes some key data in way that isn’t backward-compatible with GnuPG 2.0 and earlier, so if you want to go back later, you can do mv ~/.gnupg ~/.gnupg21 && mv ~/.gnupg-GOOD ~/.gnupg.

Otherwise, some basic steps to run to check you’ve got a working GnuPG environment:

• run gpg2 -K --keyid-format SHORT, to check that you have at least one key pair

If the output of that shows you have no secret key for GnuPG to use, you need to create one:

• run gpg2 --gen-key, to have GnuPG walk you through the steps for creating a key pair

If you get an error message saying “Inappropriate ioctl for device”, do this:

• run export GPG_TTY=$(tty) and/or add that to your ~/.bashrc or ˜/.bash_profile

Git needs to know which key it is signing with.

After you have setup GPG, gpg-agent, and your gpg.conf files (see this guide), you need to run

git config --global user.signingKey EB11C755

Obviously, replace the public key at the end with your own. If you want every commit to be signed by default, use

git config --global commit.gpgsign true

$ gpg2 -K --keyid-format SHORT          # <-- Shows your keys, e.g.:
/home/<username>/.gnupg/pubring.kbx
-------------------------------
sec   rsa4096/0754B01E 2019-02-02 [SCA]             <--secret key
      C396BF3771782D7691B0641145E11B080754B01E
uid         [ultimate] John Doe <[email protected]>
ssb   rsa4096/A20AB8EC 2019-02-02 [E]               <--public key

sec   rsa4096/25C504D5 2019-02-02 [SCA] [revoked: 2020-06-01]
      08BFF49B9E07E4B4B0C4946B645B6C1425C504D5
uid         [ revoked] John Doe <[email protected]>
uid         [ revoked] [jpeg image of size 2670]

Where A20AB8EC is the key ID you're looking for from this example.