@rysiek @Em0nM4stodon While there can be a hypothetical protocol, I'm concerned about the slippery slope.
Org A could offer a service of providing age verification. "Yes, token <blah> is an adult."
Org A will keep some ID record for liability protection. (Token <blah> is person X.)
Those records will leak, be sold/acquired, be shared with government, etc.
Software isn't the problem. (Bad) people are the problem. Even "good" people doing "tough" things for "the right" reasons.