Git noob here.
I know this is against the principal of \"distributed source control\" but I want to \"password protect\" certain development branches in my GIT repos
You can have a separate repository cloned from the public one with its own branches.
This repository could be in the filesystem with the right ACLs or group permissions, or it could be a separate server requiring proper login credentials, etc. Then developers could commit, pull, merge, etc. as authorized.