Thanks for that info.

So, then, if Apple wanted to adopt a similar solution to Google - i.e. for their own enterprise security, as opposed to for their customers - could they use one of the Yubikey NFC options, or, would they have to ‘create’ a Bluetooth-specific device?

Maybe the long-rumoured Steve Jobs ring could take the form factor?!

And from an Apple customer perspective, is there a valid argument to be made that iOS devices can be, or are currently, less secure than Android counterparts because of the current lack of Yubikey / U2F options?