Testing an old idea: NFC-based transient accounts: accounts that log off as soon as the app goes to the background, deleting all traces of the account from the phone.
It looks like this in debugging...
I'd vote up for that option. The password-encrypted NFC is easy enough to use on any phone and to write. Cheap prices per unit and basically any wearable nowadays can be a hidden NFC tag.
This would make it very hard to even find the NFC, let alone decrypt the key afterwards when it is done right.
This would make it very hard to even find the NFC, let alone decrypt the key afterwards when it is done right.