The proper solution is one we had with desktop computing for decades. If you keep the key material on your eID or bank card, you don't need a locked down operating system. Which then allows devices to live for much longer.
We're slowly losing the war on General Purpose Computing.
https://media.ccc.de/v/28c3-4848-en-the_coming_war_on_genera...
So you want a bank card/ID card to be required each time you use Google Pay? What's the point of Google Pay then.
Maybe I could even duct-tape it to my phone if I really want to do that.
From then your Google Pay account is authorized to initiate charges until you tell your bank otherwise and you don't need the card again unless you want to sign up for Venmo etc.
And it makes things easy if someone steals your phone, because you just sign into the payment processor and deauthorize the device or, if they've already changed your password etc., sign into (or go to) the bank and deauthorize the payment processor.
That then allows you to do secure NFC credit card payments even on a rooted phone with custom ROM.
Not a great solution.
Which hasn't been an issue since Chip & PIN became required, 22 years ago (at least over here).
The problem being that there are many millions of people who can't afford to replace a phone they only recently bought just because the vendor never updates it, which means those banks and things can't in practice demand that people do that. Indeed, it creates the opposite problem, because installing a custom ROM on that device would give it a patched kernel but cause it to fail attestation, so what the attestation is actually doing is requiring those people to continue to use the vulnerable OS.
A lot of phones don't receive any upgrades after 1 or 2 years...
I wish that Google would have forced vendors to implement a proper hardware abstraction (uefi or similar) so that a single kernel could run on any smartphone, just like it's the case for PCs...
https://source.android.com/docs/core/architecture/kernel/gen...