I am very aware of "designing a security system they themselves cannot break" and the difficulties of key management etc.
Would be interested in knowing more from smarter people
(probably need to build a poc - one day :-( )
We have the penetration
(Afaik smartphone penetration is around 4.5-5 BN, and something like 50%+ have secure enclaves but honestly Indont follow that deeply so would defer to more knowledgeable people)
There isn’t a widely deployed public key network with keys that represent a person, afaik. PGP is the closest maybe?
They don't own a key pair. They carry one around, which is owned by google or some other entity?