Quote from: greenearplugs on July 28, 2014, 08:30:01 PM

Quote from: AliceWonder on July 28, 2014, 07:47:21 PM

Quote from: Beliathon on July 28, 2014, 07:00:55 PM

Quote from: AliceWonder on July 28, 2014, 08:50:43 AM

Yes but part of the appeal of crypto is you don't have to use payment processor.

If going to have the money flow through a third party anyway, why deal with the volatility?

Because volatility is temporary, while increasing value is permanent. For fiat scrip, decreasing value is permanent. I'll leave the math to you, detective.

Joe empties his phone. Sends half a btc to his phone as dust inputs. Goes to Raley's, all his inputs are dust resulting in a very large kb transaction of fresh dust - which he doesn't pay a fee on. When will the transaction be confirmed?

Meanwhile his shell script detects the spend, waits for two failed confirmations (at which point Joe is long gone) and then double spends them with a transaction fee.

Miners see the transaction with a fee and confirm it. Didn't cost Joe anything, worst case scenario is some miner confirms the first spend and he pays for his groceries. Normal scenario, he's already in his car by the time the next block happens and long gone by the time the grocer sees 2 blocks w/o a confirm.

wouldn't it be fairly easy for a merchant wallet to check for this type of thing. If any of the above scenarios are true, then the customer would have to wait for full confirmation. Basically, wait 10 seconds, have the merchant wallet check for double spends. 10 seconds is enough of a head start that the first transaction should be propagated to enough of the network to make double spending unpractical.

Satoshi addressed this here. Are there any flaws in his plan?:

https://bitcointalk.org/index.php?topic=423.msg3819#msg3819

So what happened to Satoshis theory As this person stated?

Satoshi's comment PASTED IN HERE VV
*********************
I believe it'll be possible for a payment processing company to provide as a service the rapid distribution of transactions with good-enough checking in something like 10 seconds or less.

The network nodes only accept the first version of a transaction they receive to incorporate into the block they're trying to generate. When you broadcast a transaction, if someone else broadcasts a double-spend at the same time, it's a race to propagate to the most nodes first. If one has a slight head start, it'll geometrically spread through the network faster and get most of the nodes.

A rough back-of-the-envelope example:
1 0
4 1
16 4
64 16
80% 20%

So if a double-spend has to wait even a second, it has a huge disadvantage.

The payment processor has connections with many nodes. When it gets a transaction, it blasts it out, and at the same time monitors the network for double-spends. If it receives a double-spend on any of its many listening nodes, then it alerts that the transaction is bad. A double-spent transaction wouldn't get very far without one of the listeners hearing it. The double-spender would have to wait until the listening phase is over, but by then, the payment processor's broadcast has reached most nodes, or is so far ahead in propagating that the double-spender has no hope of grabbing a significant percentage of the remaining nodes.
**********************************

Or is this what payment processors do already and we are talking about something quicker here?

Just curious has anyone looked at the other coins, and why are some stating HIGH security even more than BTC or same + MUCH faster transaction times... I just don't get it, cant we just implement the same thing? Many test coins around.