Oh, that's my bad, I re-read the privacy pass protocol to brush up and it does use signing without requiring the RP to necessarily make another call to the orig

Oh, that's my bad, I re-read the privacy pass protocol to brush up and it does use signing without requiring the RP to necessarily make another call to the original approver server. I also see there's been work on hidden witness ZKP, so the RP may not even know who approved a given token. Very cool! Always happy to be proven wrong with cool tech!