Earlier quoted context omitted.
Really, how? At some point someone will need to issue a key, which at some point will need to be verified against known good signatures. These signatures will also need to be kept in case of lawsuirs/enforcement, so if somebody gets access they will know you visited that site
Parental controls on device are a better solution that work today and don't carry a risk of data breach.
Do they work currently? Not really
Are they too complex for the avg joe to work out. Unfortunately yes. (Something about the smartest bears and the dumbest humans)