Post
Topic
Board Development & Technical Discussion
Re: How I'd like it to work (Bitcoin face-to-face) feel free to steal idea
by
xc
on 21/06/2011, 00:39:35 UTC
This scenario could be handled nicely with the concept of listening nodes:

Transactions are nearly instantaneous.  It's traditional network confirmations that require tens of minutes.  However, as explained by Satoshi, merchants can significantly reduce the probability of a double-spend through the use of a listening period:

https://en.bitcoin.it/wiki/Myths#Point_of_sale_with_bitcoins_isn_t_possible_because_of_the_10_minute_wait_for_confirmation
http://forum.bitcoin.org/?topic=423.msg3819#msg3819

The longer the listening period the greater the assurance that the transaction will be confirmed as is. 10-30 seconds would probably be sufficient.  Theoretically, it's possible that the attacker might have a huge cache of hidden miners that would only accept his version of the transaction.  But this seems highly unlikely and a huge waste of effort for skimping on a simple meal.  It's so much less likely that a payment processor offering the listening node service could likely guarantee the restaurant's payments for a fee far less than what banks charge for the use of credit cards.