Last updated March 13, 2024
This Gist explains how to sign commits using gpg in a step-by-step fashion. Previously, krypt.co was heavily mentioned, but I've only recently learned they were acquired by Akamai and no longer update their previous free products. Those mentions have been removed.
Additionally, 1Password now supports signing Git commits with SSH keys and makes it pretty easy-plus you can easily configure Git Tower to use it for both signing and ssh.
For using a GUI-based GIT tool such as Tower or Github Desktop, follow the steps here for signing your commits with GPG.
Ideas are cheap. Make a prototype, sketch a CLI session, draw a wireframe. Discuss around concrete examples, not hand-waving abstractions. Don't say you did something, provide a URL that proves it.
Nothing is real until it's being used by a real user. This doesn't mean you make a prototype in the morning and blog about it in the evening. It means you find one person you believe your product will help and try to get them to use it.