One potentially interesting point of discussion here is to compare GitHub to PGP keyservers. Both provide a means of sharing someone’s keys with a wide audience. GitHub probably has gotten more people actively using SSH keys than are actively using PGP to encrypt or sign material.
Then there’s the more controversial possibility that with such a large userbase, SSH could encroach on what was traditionally PGP’s territory. Giving someone a new account with password “changeme” is already long obsolete. How about when SSH signatures become mainstream? https://mobile.twitter.com/damienmiller/status/1452796122250...
If you have your system set to automatically use said key other SSH servers you connect to can tie that to your github user, which technically is a privacy leak, but generally not a serious concern. But if you want to keep a github (or other) account private, take care to give it a dedicated key and only have git/SSH use it when connecting to that specific site.
It's not because I think it's exploitable in any way (it's not - public keys are public), but because it's a neat feature I found interesting that many people don't know about. It also has potential use cases, like automatically keeping a machine's authorized_keys up to date with members in a team, or skipping having to ask for someone's public key when sharing access.
Funny, I was just trying to use Git for Windows the other day, and was completely unsuccessful without authentication, even just to pull a public repo.
Not a huge deal in and of itself? Good key management processes would have you rotate every so often. However, we probably have a lot/most/all of us that use the same SSH key for many systems and loss of that private key would be compromise of your Github account.
Have a unique username / password combination for each website, right? Same is true for Github and all other SSH systems.
Also, Github provides Security Key support if you want to go that route. SSH keys are really not that different than passwords, but they seem more complicated, so maybe they are?
Then there’s the more controversial possibility that with such a large userbase, SSH could encroach on what was traditionally PGP’s territory. Giving someone a new account with password “changeme” is already long obsolete. How about when SSH signatures become mainstream? https://mobile.twitter.com/damienmiller/status/1452796122250...