https://www.theregister.co.uk/2018/08/01/unhackable_bitfi_wallet/

Pics A crypto-currency wallet heavily promoted as "unhackable" – complete with endorsements from the security industry's loopy old uncle John McAfee and a $350,000 bounty challenge – has, inevitably, been hacked within a week.

The $120 Wi-Fi-connected Bitfi wallet is a hardware device that stores your crypto-coins and assets, and requires a passphrase to access these goodies. The phrase is used to temporarily generate, for a few milliseconds, the private key needed to unlock the data, and is then discarded. So without the passphrase, you can't get at the gizmo's fun bux, allegedly.