Quote from: drazvan on November 02, 2013, 12:23:47 PM

In the case of the OtherCoins, we're definitely not "holding bitcoins on the user's behalf". They're Bitcoins and remain Bitcoins, accessible at any time without contacting any external servers. The idea is to just allow them to be passed on to another person without going through the blockchain, but they can be used on the Bitcoin network just as easily - the OtherCoin smartcard simply makes sure that you can only do one or the other - it keeps parties honest, it doesn't hold your bitcoins.

If you read this thread, you'll see that it doesn't have the notion of Bitcoins and balances and doesn't even know what address you're using.

I'm not sure if this reply is directed at me or at justusranvier. If it was at me, I would like to say that I do understand what you scheme is: it is very similar to this one that I outlined as an example of an electronic off-chain transaction using DRM on personal computers and phones- https://bitcointalk.org/index.php?topic=148232.msg1578079#msg1578079 (elsewhere in that thread I even say that it is possible to use smart cards).

The reason I mention bank-like off chain transactions above was because for most people conducting off-chain transactions with large amounts of money they would prefer the safety and reassurances that a bank like institution provides (eg: similar to how in the real world not many every day citizens by new cars/houses/businesses with cash-- they use bank cheques and the like).

Local off-chain electronic private key transfer is a great alternative for smaller items and would appeal to the masses, it would be very convenient for transactions like buying groceries and petrol etc. Most people would accept the security risk associated for small amounts like this (eg: in the current fiat world few people here in Australia have reservations loading bus cards with a $20-to-$100 or so). However, personally I wouldn't use private key transfer for anything more than a few thousand and I think will you find that many people wouldn't even use it for that much-- maybe just a few hundred.

There is a real need for your scheme and it is a great development. Previously I've offered 50BTC for an open-source smart phone version for secure private key transfer, however at the moment smart-phones don't seem to have the necessary hardware-- Samsung KNOX comes close. So I'll pledge 15BTC to your smart card idea on successful completion and public release (non-open source accepted).