2 ms·

So now let's assume I'm selling something on an auction site and someone pays me with coins where I assume it's likely that they are stolen (but I don't have an

by gst 13y ago

So now let's assume I'm selling something on an auction site and someone pays me with coins where I assume it's likely that they are stolen (but I don't have any definite knowledge about that). For some reason I now need to refund the buyer. Do I now first need to transfer all but 0.1 coins to somewhere else, so that I can send the remaining 0.1 coins back?

eterm 13y ago
Why are you dealing with money that you're assuming that is likely stolen? If they turn out blacklisted then you're out of pocket. Because bitcoin does not support refunds or chargebacks you must transfer clean money to refund them. Bitcoin has weaknesses, the way it deals with "change" and indeed the need for change is one of them. Bitcoin should have dealt with the change issue by instead of the splitting happening at the receiver end and sending back change, the splitting should have happened at the sender end so only the correct amounts were ever sent.
- yebyen 13y ago
  That's not really how it works. The sender does the splitting, but he has to send the change somewhere, and customarily it's sent to a new address. The receiver doesn't even have to be online, you don't get your change from them, so the only way you'd get blacklisted coins in change is if you already had some blacklisted coins in the inputs you were using to begin with.
Dylan16807 13y ago
>Do I now first need to transfer all but 0.1 coins to somewhere else, so that I can send the remaining 0.1 coins back? You make it sound like this is a burden. It seems easy to me, as long as you track taint per-output rather than per address. Just pretend people followed best practices and used a unique address for every output. So let's take eterm's suggestion that clean coins always come out first. So all we need to do is build a transaction with at least .1 tainted coins, put the non-refund coins as the first output, and put the .1 tainted coins as the second output. First output is an address we control, second output goes back to the person we're refunding. That's assuming you already mixed up your coins and can't just send back the exact same transaction they sent you in the first place.

by gst 13y ago

eterm 13y ago

Why are you dealing with money that you're assuming that is likely stolen? If they turn out blacklisted then you're out of pocket. Because bitcoin does not support refunds or chargebacks you must transfer clean money to refund them. Bitcoin has weaknesses, the way it deals with "change" and indeed the need for change is one of them. Bitcoin should have dealt with the change issue by instead of the splitting happening at the receiver end and sending back change, the splitting should have happened at the sender end so only the correct amounts were ever sent.

yebyen 13y ago
That's not really how it works. The sender does the splitting, but he has to send the change somewhere, and customarily it's sent to a new address. The receiver doesn't even have to be online, you don't get your change from them, so the only way you'd get blacklisted coins in change is if you already had some blacklisted coins in the inputs you were using to begin with.

Dylan16807 13y ago

>Do I now first need to transfer all but 0.1 coins to somewhere else, so that I can send the remaining 0.1 coins back? You make it sound like this is a burden. It seems easy to me, as long as you track taint per-output rather than per address. Just pretend people followed best practices and used a unique address for every output. So let's take eterm's suggestion that clean coins always come out first. So all we need to do is build a transaction with at least .1 tainted coins, put the non-refund coins as the first output, and put the .1 tainted coins as the second output. First output is an address we control, second output goes back to the person we're refunding. That's assuming you already mixed up your coins and can't just send back the exact same transaction they sent you in the first place.