Honestly we need a law that says that _all_ keys used in your car (software and physical) need to be given to you. This should include the keys to sign the updates, manage the CAN networks, etc.
Even ignoring the automaker lobby's inevitable opposition, this would never happen because one could use it to defeat things like emissions controls or the coming anti-impairment technology[1].
1: https://apnews.com/article/coronavirus-pandemic-joe-biden-te...