After you've set up your GPG key and added it to your GitHub account, you need to inform Git that there's a GPG key you'd like to use.

If you're using a GPG key that matches your committer identity and your verified email address associated with your GitHub account, then you can begin signing commits and signing tags.

If you don't have a GPG key that matches your committer identity, you need to associate an email with an existing key.

If you have multiple GPG keys, you need to tell Git which one to use.

  1. Open TerminalTerminalGit Bash.

  2. Use the gpg --list-secret-keys --keyid-format LONG command to list 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.

  3. From the list of GPG keys, copy 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 
    ssb   4096R/42B317FD4BA89E7A 2016-03-10
    
  4. To set your GPG signing key in Git, paste the text below, substituting in the GPG key ID you'd like to use. In this example, the GPG key ID is 3AA5C34371567BD2:

    git config --global user.signingkey 3AA5C34371567BD2
    

Further reading