Add GPG key to Git

#cryptography #customization #git #gpg #linux #pgp #dotfiles

Prerequisites

Instructions

Open Terminal.
If you have previously configured Git to use a different key format when signing with --gpg-sign, unset this configuration so the default format of openpgp will be used.
```
git config --global --unset gpg.format
```
Use the gpg --list-secret-keys --keyid-format=long command to list the long form of the GPG keys for which you have both a public and private key. A private key is required for signing commits or tags.
```
gpg --list-secret-keys --keyid-format=long
```
Note

Some GPG installations on Linux may require you to use gpg2 --list-keys --keyid-format LONG to view a list of your existing keys instead. In this case you will also need to configure Git to use gpg2 by running git config --global gpg.program gpg2.

From the list of GPG keys, copy the long form of the GPG key ID you'd like to use. In this example, the GPG key ID is 3AA5C34371567BD2:

$ gpg --list-secret-keys --keyid-format=long
/Users/hubot/.gnupg/secring.gpg
------------------------------------
sec   4096R/3AA5C34371567BD2 2016-03-10 [expires: 2017-03-10]
uid                          Hubot <hubot@example.com>
ssb   4096R/4BB6D45482678BE3 2016-03-10

To set your primary GPG signing key in Git, paste the text below, substituting in the GPG primary key ID you'd like to use. In this example, the GPG key ID is 3AA5C34371567BD2:
```
git config --global user.signingkey 3AA5C34371567BD2
```
Alternatively, you may want to use a subkey. In this example, the GPG subkey ID is 4BB6D45482678BE3:
```
git config --global user.signingkey 4BB6D45482678BE3
```
If you use multiple keys and subkeys, then you should append an exclamation mark ! to the key to tell git that this is your preferred key. Sometimes you may need to escape the exclamation mark with a back slash: \!.
Optionally, to configure Git to sign all commits and tags by default, enter the following command:
```
git config --global commit.gpgsign true
git config --global tag.gpgSign true
```
For more information, see Signing commits.
To add your GPG key to your .bashrc startup file, run the following command:
```
[ -f ~/.bashrc ] && echo -e '\nexport GPG_TTY=$(tty)' >> ~/.bashrc
```

Source

https://docs.github.com/en/authentication/managing-commit-signature-verification/telling-git-about-your-signing-key