How a Restaurant can Implement BTC

[Dafar]

The risk is that someone can write a special wallet program that can send two transactions that spend the exact same bitcoins.  One transaction would be paying the merchant (which the merchant would see), and the other would send the bitcoins to a different address that you own (the merchant probably won't even see that transaction until it is confirmed). Only one of those transactions will become confirmed and added to the blockchain.  Once one of the transactions is confirmed, the other transaction will become invalid and all peers will discard it.  This is not an easy or reliable process, and it is obviously fraud (just like writing a bad check, or falsely claiming fraud on a credit card transaction).  It would be faster, easier, and more reliable for the customer to simply get up and walk out of the restaurant without paying than it is to try and successfully pull off this 0 confirmation fraud.

I see, thanks!

[MOON_2000]

So how do u handle 0 confirmation tx's

The places I have eaten never wait for confirmation. It does require some trust on their part, but so does a check or even a cash. The cash may be found to be counterfeit later on. It is worth trusting in these cases because faking it would be a bigger hassle than just paying the bill.

Yes, I am sure were will see a low percentage of fraud here.

[coinbling]

I

[BittBurger]

Latin House Grill in Miami (Kendall) does this.  No BitPay needed.

1)  Open up Blockchain app
2)  Type in the Bitcoin amount and the app tells you exactly how much USD it equals while you type.
3)  Fine tune it until correct
4)  Submit.

No merchant fees for Latin House Grill (even low ones via BitPay).
Fortunately for them, Bitcoin went up significantly since I paid $52 for our dinner.
I have now paid them $70 for dinner :-P
Fortunately I replenished *my* bitcoin immediately.

-B-

[Ron~Popeil]

The risk with 0 is no more than the risk of charge backs and traditional fraud. There will always be a percentage of the population that seeks to defraud and steal. Bit coin is not immune to this. 

[TheTruth4]

Use BitPay. They will help. They have retailer solutions

[doof]

Buy a coinkite terminal.  Works well.  Great support team.  Looks like other EFTPOS (Credit card) hardware, so staff dont require much training.  Auto forwarding at the back end too.

[Ron~Popeil]

Quickbooks will be adding bit coin to its POS systems soon as well.

[zimmah]

Thanks, I was a little iffy about the confirmations. Basically.. if you required even 1 confirmation you need to wait 10 minutes right?

The average time between confirmations is 10 minutes. Sometimes they can happen in less than a second, or they can take over an hour.

If you require 0 confirmations, the merchant gets his money instantly, right?

It's not the sender that decides how many confirmations are required, the merchant decides how many confirmations they want to wait for.  The transaction will typically show up in the merchants wallet in less than 5 seconds (often less than a second). At that time it will have 0 confirmations.

But what is the risk? Can someone send a "fake" bitcoin and get away with it?

The risk is that someone can write a special wallet program that can send two transactions that spend the exact same bitcoins.  One transaction would be paying the merchant (which the merchant would see), and the other would send the bitcoins to a different address that you own (the merchant probably won't even see that transaction until it is confirmed). Only one of those transactions will become confirmed and added to the blockchain.  Once one of the transactions is confirmed, the other transaction will become invalid and all peers will discard it.  This is not an easy or reliable process, and it is obviously fraud (just like writing a bad check, or falsely claiming fraud on a credit card transaction).  It would be faster, easier, and more reliable for the customer to simply get up and walk out of the restaurant without paying than it is to try and successfully pull off this 0 confirmation fraud.

It's not as simple as that to doublespend. If you send two transactions simultaneously the network will see it, I believe. You'd have to give the real transaction a head start so the network does not have enough time to mark the transaction as a double spent, yet on the same time you should not wait too long, or else the fraudulent transaction will not be able to beat the original transaction. For this reason doublespend attempts often fail.