The idea of faces changing is handled by the idea of regularly (perhaps once a year) taking a new picture of yourself and having it re-attested by witnesses (perhaps ones randomly chosen, within reason, by a third party). Algorithms or human judges can then give a credibility score of whether the person is genuinely ageing over time or reusing a batch of old pictures, for example.
As for the issue of prosopagnosia, that's interesting, I hadn't thought of that. I think that faces could be used just as a bootstrap, equivalent to a "forgot my password" process, to enable someone to associate a blockchain-facial identity to a public key generated on a device. (Also, apparently people with one type of the condition, associative prosopagnosia can have the ability to answer "same/different" about two pictures, even if they can't tell you who is in the pictures.)
I haven't seen a full threat model or a fleshed out protocol of how all the pieces in the system would interact, but it's good to hear some of the hurdles it would need to overcome, thanks.
As for the issue of prosopagnosia, that's interesting, I hadn't thought of that. I think that faces could be used just as a bootstrap, equivalent to a "forgot my password" process, to enable someone to associate a blockchain-facial identity to a public key generated on a device. (Also, apparently people with one type of the condition, associative prosopagnosia can have the ability to answer "same/different" about two pictures, even if they can't tell you who is in the pictures.)
I haven't seen a full threat model or a fleshed out protocol of how all the pieces in the system would interact, but it's good to hear some of the hurdles it would need to overcome, thanks.