Yubikey PIV Manager

The Yubikey PIV Manager is a GUI tool to manage PIV-related data on a Yubikey. The command-line version can be installed via Homebrew:

❯ brew install yubico-piv-tool

The command-line utility is more powerful (e.g. allows overriding pin and touch default slot policies) but it also more prone to user errors. It's very easy to overwrite an existing key, for instance.

After downloading and installing Yubikey PIV Manager and yubico-piv-tool, insert your Yubikey. You will be prompted initialize your device.