Form the bitkey website, now go explain 2-of-3 multisig to grandma... (Not saying it's not an awesome idea) "One wallet, three keys Bitkey’s 2-of-3 multisig setup is built into every wallet. You hold two keys: one on your Bitkey device and one in the app. A third is encrypted on a server and can’t be used without one of your other keys. That means only you can approve transactions, and you’re never locked out—even if you lose a key."