>
> I wonder about the receipt step -- are you generating a PDF on device
> and sending it via NFC? This is something that could be supported by the
> BIP70 payment protocol. We should try to avoid the second tap, its not
> intuitive.
>

Together, the signed PaymentRequest and the transactions in the block chain
should act like a receipt: it's proof you requested payment in a certain
way, and I satisfied that payment. So it's proof of payment and the memo
field can describe what I bought.


> Contactless cards? Last I was to London, the Oyster card was already
> contactless. Have there ever been magnet-strip-based Oyster cards?
>

He means, contactless credit cards can be used too. No need to enroll for
Oyster specifically. I guess in the long run Oyster and its equivalents in
other cities (octopus etc) will be phased out.