Then, Chase knows you've verified your ID somewhere, the relay knows that some Chase user verified themselves at Pornhub, and Pornhub knows that the user is over 18, without knowing their identity or what bank they're using.
You could also do this with ZKPs and device integrity protection. The latter is more secure but more complex, the former is much simpler and openness friendly.
Then, Chase knows you've verified your ID somewhere, the relay knows that some Chase user verified themselves at Pornhub, and Pornhub knows that the user is over 18, without knowing their identity or what bank they're using.
You could also do this with ZKPs and device integrity protection. The latter is more secure but more complex, the former is much simpler and openness friendly.