How about this scenario - There is a site A that wants me to prove my age. Site A generates a one-time key for this request. This key is completely random an

How about this scenario - There is a site A that wants me to prove my age. Site A generates a one-time key for this request. This key is completely random and does not include any information about the identity of A or myself. The key does include the type of request being made (ie age/gender/income/etc verification) I take this key to a trusted verifier, B, that has my age information. This trusted verifier uses the key from A to generate another response key. I enter the response key into site A which decrypts it using the public key of site B. In this model, 1. Site A has performed the verification (as long as it trusts Verifier B) 2. Site A does not have any additional information about me 3. Verifier B does not know the origin of the request Of course, in an area, where only certain websites perform particular verifications (eg adult websites performing age verifications), there is some information leakage to Verifier B about my behavior