brew install gpg
LANG=C gpg --gen-key
gpg --full-generate-key

$ gpg -k
/Users/username/.gnupg/pubring.kbx
--------------------------------
pub   rsa4096 2021-01-01 [SC]
      ABCDEFGHIJKL12345
uid           [ultimate] AAAA BBBB <[email protected]>
sub   rsa4096 2021-01-01 [E]

gpg -a --export ABCDEFGHIJKL12345 > pubkey.gpg
git config --global gpg.program /opt/homebrew/bin/gpg
git config --global user.signingkey "ABCDEFGHIJKL12345"
git config --global commit.gpgsign true


brew install pinentry-mac
echo "pinentry-program /opt/homebrew/bin/pinentry-mac" >> ~/.gnupg/gpg-agent.conf
killall gpg-agent

echo "test" | gpg --clearsign