The way it looks is that it is connected to your cellphone via bluetooth or something of that sort (since it notifies you when it is out of range from your card). An easy solution would be for the card to auto wipe when disconnected from your phone, then re-download all the cards from the app when you reconnect. Problem solved!

It deactivates completely when it's been away from your phone for a certain amount of time, which you can set in the settings.

BTLE tether, card gets deactivated if its not near your phone.

Does deactivated mean erased?

From what I understand...there is some sort of memory chip on the card that stores the credit card numbers and info for every card, right?

So what is to stop some chip from bypassing the OS that manages the multiple cards and just reads the raw data?

Sure, it may be 128-bit encrypted, but if they have the raw dump - then it's just a matter of brute forcing it to eventually crack it...no?

What am I missing here?

Well if the coin can be deactivated when it's out of range, that would mean the coin has to be "smart" because it wouldn't be the phone app doing the deactivation but the coin itself. In that case, why couldn't the coin take extreme measures and just wipe its memory? Inconvenient for legitimate situations where the card is out of range and not accidental ones, but I imagine it's quick process to reload the coin with your card(s) data.

Deleting the data to later copy back from the phone doesn't sound extreme or inconvenient to me.

I agree that it COULD be a possibility, but is it?

Brute forcing 128 bit encryption, depending on the algorithm used, is not trivial.

Remember, the difficulty goes up EXPONENTIALLY for every bit you add.

Never said it was trivial.

Just that it is much easier to do that - when you can set computer power to it locally. i.e. you can download all the credit card data onto your local hard disk and throw computing power at it....as opposed to trying to compromise a remote server that may be monitored.

'just' a matter of brute-forcing?

No comment.

Yeah, they probably didn't think about that.

eh, for me at least, if they have my Coin card, they probably have my wallet.