Besides, 10 minutes is too long to verify that payment is good. It needs to be as fast as swiping a credit card is today.
See the snack machine thread, I outline how a payment processor could verify payments well enough, actually really well (much lower fraud rate than credit cards), in something like 10 seconds or less. If you don't believe me or don't get it, I don't have time to try to convince you, sorry.
http://bitcointalk.org/index.php?topic=423.msg3819#msg3819^ Thank you! That is a great post by
satoshi that is saying about the exact same thing! I should go read all his posts. There is some wisdom there!
Other people argue differently in that same thread. Spitting out 2 spends from the same time is easily done. It can work enough to be a valid attack. That is why everyone insists on at least a confirmation for transactions of any significance.
The problem is that for people are fascinated by the pure technical aspect of being able to spend digital money, this wait time causes a severe problem. The answer of the koolaid drinkers is not better technology, it is layering on kludges to fix the problem.
Yes, but if two simultaneous spends get detected then both transactions can be cancelled. And if one of the transactions was first, even if only by seconds, then it will propagate a majority of the network more quickly (exponentially) and be accepted by miners while the second one is rejected. This is as satoshi explains in his post (see link in OP).
This would be coded by payment processors to make the threat of double spends a non-factor. satoshi explains this and it makes sense if you think about how it could be implemented.
It helps if you can think like a programmer to imagine how this would be implemented in a workable fashion and all its ramifications.
I assume a cancelled transaction does not meant funds are lost, just sent back. This means the cost of the attack is too close to 0.
There are reasons people who think like programmers and want funds fungible ASAP still rely on confirmations.
Bitshares fixes this and the scalability factor at the expense of managed centralization. This centralization is in fact less than the current bitcoin centralization which centers around a handful of mining pools. Effectively meaning that the BTC network is controlled by as many people as I can count on one hand.