That's more or less how AT works, minus the Torrent part. There's a private key you own (which is normally held on your hosting but you can also add a "higher priority" key that would override that one if your relationship with your hosting sours). The updates are broadcasted by WebSockets but you can think of it similar to RSS. The repo is MST but that's not too far from Git. The commits are signed. The publishing is done on traditional web though.