>Ssl certificates have been facing this problem for years.
That's an entirely different, and much easier problem. In the case of SSL you are not worried about an attacker obtaining a certificate for any host, just the ones you care about. E.g. an attacker getting a certificate for facebook.com would be catastrophic, but an attacker getting a certificate for a website that no one uses would be a non-issue.
For the case of avoiding deepfakes, you need to avoid the attacker extracting a key from any of the millions of cameras that are sold every year.
That's an entirely different, and much easier problem. In the case of SSL you are not worried about an attacker obtaining a certificate for any host, just the ones you care about. E.g. an attacker getting a certificate for facebook.com would be catastrophic, but an attacker getting a certificate for a website that no one uses would be a non-issue.
For the case of avoiding deepfakes, you need to avoid the attacker extracting a key from any of the millions of cameras that are sold every year.