GitHub supports several GPG key algorithms. If you try to add a key generated with an unsupported algorithm, you may encounter an error.
Note: GPG does not come installed by default on OS X or Windows. To install GPG command line tools, see GnuPG's Download page.
Open TerminalTerminalGit Bash.
gpg --list-secret-keys --keyid-format LONGcommand 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 LONGto view a list of your existing keys instead. In this case you will also need to configure Git to use
git config --global gpg.program gpg2.
Check the command output to see if you have a GPG key pair.