Hm, I’m reading the spec. It seems more simplistic than I was expecting.
Issuance of Proof of Age attestations (step 3)
Once the User’s age has been verified, the AP may either issue the Proof of Age attestation directly to the User’s AVI or generate a pre-authorized code and provide it to the User as part of a credential offer. At a later stage, the User can present this credential offer through their AVI to obtain the Proof of Age attestation.
Confirmation and presentation (step 5)
The AVI receives the Proof of Age request and presents it to the User. The User reviews the request details, verifies the information, and confirms the transaction to proceed.
The AVI securely transmits the Proof of Age attestation to the RP.
Guess it does just pass the attestation around.
2.2.3 Revocation and Re-Issuance
In its current form, the solution does not support revocation or re-issuance. Adding support for these features would introduce additional complexity, which could hinder the rapid adoption of the solution.
The attestation is ideally only used once and issued in batches, so this is both good and bad I guess, since if they ask to track you and they haven’t already recorded all the attestations, they’ll need to wait for you to generate more.
Unlinkability: The goal of the solution is to prevent user profiling and tracking by avoiding linkable transactions. Initially, the solution will rely on batch issuance to protect users from colluding RPs. Zero-Knowledge Proof (ZKP) mechanisms will be considered to offer protection. More details are provided in Section 7.
Basically a big TBD. Lovely.
The more subtle attack you mention could probably be avoided if the root certs and so on or whatever equivalent they’re using are public and you check that the attestation given to you doesn’t include extraneous details (which ideally the app would do for you). Not sure how that’ll interact with the zkSNARK solution provided as an “experimental feature.”
It doesn’t really matter though since they can just record the attestations when they’re issued, so they just have to say “look for these attestations” to whatever site and they can track your visits.
It is recommended that the Proof of Age attestation be designed as a single-use credential and remain valid for a maximum period of three (3) months from the date of issuance. If a revocation mechanism is required, a status list may be utilized as an effective solution for managing the revocation status of attestations.
Of course, using it in batches is only “recommended,” so I guess they could just issue it once and continuously reuse it, in which case it would be very easy for websites to link it to you.
There’s probably more I could pull out, but yeah, doesn’t seem great based on the spec :|
Hm, I’m reading the spec. It seems more simplistic than I was expecting.
Guess it does just pass the attestation around.
The attestation is ideally only used once and issued in batches, so this is both good and bad I guess, since if they ask to track you and they haven’t already recorded all the attestations, they’ll need to wait for you to generate more.
Basically a big TBD. Lovely.
The more subtle attack you mention could probably be avoided if the root certs and so on or whatever equivalent they’re using are public and you check that the attestation given to you doesn’t include extraneous details (which ideally the app would do for you). Not sure how that’ll interact with the zkSNARK solution provided as an “experimental feature.”
It doesn’t really matter though since they can just record the attestations when they’re issued, so they just have to say “look for these attestations” to whatever site and they can track your visits.
Of course, using it in batches is only “recommended,” so I guess they could just issue it once and continuously reuse it, in which case it would be very easy for websites to link it to you.
There’s probably more I could pull out, but yeah, doesn’t seem great based on the spec :|