Bitcoin Forum

One thing I'm still not sure I understand about bitcoin's viability to work in real world stores - is how long it takes for payments to process.

How does this work from a store owner's perspective? How can you be sure you will get your money if someone walks in and offers to pay via bitcoin?

Would the customer not have to wait there with you until the transaction is confirmed to avoid the possibility of being scammed somehow?

Thanks in advance for any answers.

Thats vendors discretion. But we and the other shops in 18b Las vegas just need to see that its sent to chain and sale is finalized then.Like the BTMs same instant blockchain sees it they pay out.

Ahah that is interesting. Thanks for the information. Would you say there is any risk for vendors or is it rare to have problems?

2 years ,76 local stores never 1 bad transaction

 Edit alot of the stores take many other coins beside bitcoin and all as soon as the chain sees the trans . it is yours and that has been always within seconds.

That counts as rare! Right that has really cleared that up for me - thanks so much for the advice chief!

Anytime! and now the plug When In las Vegas 18b The Arts District where Vegas and crypto meet .lol

If your store/shop is going crypto . 1. have a sign up sheet get their twitter,FB and social media links .So you can send enticing product pics with a crypto only price and that gets their friends and family involved.

Looks like an interesting place!

Really cool tip, thanks! I am still in really early stages but useful to know, cheers! Have a great weekend :)

Good luck and Welcome aboard.

It is always good to see a member here interesting in investing in a shop that accepting BTC as payment.  I would accept most other forms of payment as well.  Welcome to the forum and good luck with your business idea. :)

There is ALWAYS risk with ANY form of payment.

If you are accepting U.S. dollars, there is a risk that you will accidentally accept high quality counterfeit bills. You may not know this has happened for a day or so until you try to deposit the bill at the bank.  By then, it may be difficult to recall many details about the person that gave you the counterfeit when you talk to the police and they attempt to track down the criminal.

If you are accepting credit cards, there is a risk that a chargeback may occur against your business for a variety of reasons.  If it is due to credit card fraud, you may not know this has happened for several weeks (or even months). By then, it may be difficult to recall many details about the person that used the credit card when you talk to the police and they attempt to track down the criminal.

If you are accepting bitcoins, there is a risk that they will successfully get a replacement transaction confirmed before the transaction that you see is confirmed.  You may not know that this has happened for an hour or so.  Of the three situations we've discussed here, you have the best chance of recalling some details about the thief when you contact the police in this situation.

Furthermore you can create software that checks some very simple details that will drastically reduce the risk when accepting bitcoin transactions.

If you verify that:

• Your wallet is well connected to multiple geographically distributed peers (or directly connected to several large mining pools)
• The transaction has been well propagated (especially if your software has heard about the transaction from several large mining pools)
• The transaction includes a reasonable fee per kilobyte
• All inputs to the transaction are already confirmed

Then you can be VERY confident that the transaction will confirm.  It would be extremely difficult (nearly impossible) to reverse such a transaction.  I'd personally feel comfortable accepting a transaction worth hundreds of dollars without confirmation if it met the criteria above.
  

If a transaction has the appropriate fees attached, there is little risk.  However that does not mean that there is no risk.   Use you judgement.   If it's for more than a few dollars, I think most people won't mind waiting 10-20 minutes for a confirmation or two.

with small transaction there should be any problem in accepting them with no confirmation, for large transaction it would be a problem if the shop require you to wait for one confirmation, worst case you can more fee to speed it up in the queue

but I always thought that bitcoin is more of an online for of payment, where the waiting isn't that important and will not cause discomfort like in real life payments

i think it can depend on the payment size. for example if it is only 1-2 dollars it is ok to accept it without any waiting and just knowing that it was sent to you.but for bigger purchases i think you have to wait for at least one confirmation to be sure.

also you might be able to use off-chain wallets like coinbase or xapo since they are not using blockchain to confirm it is done right away so you dont have to wait.

I suppose they would have to order in advance and collect their product once the transaction processes. Would work better if the shop had a website or online presence of some kind

A payment takes 10 min to process. In what store can you buy something under 10 minute really?

Sometimes you have to wait 15 min at the tilt because the employee is a moron, if you could do that in 10 min i`d be very happy.

You just buy the stuff quick, pay for it, then put the bought stuff in a safe storage inside the magazine, and go looking at the other products until you wait for verification. Then after the verification is done, pickup your bought goods and leave.

It would change shopping habits, but whatever.

 No ,that would make people leave..Really once blockchain see's the transaction you are good .i have stood their and tried to double spend and never succeeded(Testing) So , if you really want bitcoin to be used by the masses . Maybe try going to a real store and spending some ?

Not all blocks take 10 minutes, that's the average time but some of them I have seen to take more than an hour. It is a minor problem and it has been discussed before but if any store does starts to accept BTC as a payment method then the person paying with bitcoin has to wait until the Tx has received 1 confirmation because the shop owner won't accept payment until it has 1 confirmation and for now this is how it is.

Ok plan B

Have an offchain  bitcoin based payment processor designed solely for shop purchases.

You sign up to this payment processor, deposit like 2 bitcoins, and then go on shopping. When you pay for the goods & services you pay directly from the PP's account you hold with them, which would take 15 sec perhaps like if you would buy with credit/debit cards :)

This would be an easy off-chain solution, and would need a bit of technical integration from the vendor's part.

But i`m sure something like XAPO or similar could come up with an offchain system like this.

plan c

The shop itself should have an internal account with you. Most shops already give out fidelity cards, perhaps they can give out debit cards now and you can have an accoutn with them.

Especially big hypermarkets and plaza's so you just make an account there deposit 2-3 bitcoins when you enter, buy it off and then you leave you can take out the change.

Really? You are so off .
You would need some scripting knowledge as any of the default bitcoin core/qt or other wallets won't allow you to easily execute a double spend.

Any particular reason you want to try this? Just to see how resilient the protocol is? Short of having a ton of mining resources at your disposal, it's going to a bit hard to pull off even a 0 confirmation double spend since most miners will reject the transaction by comparing what's in mempool. For a 1-3 confirmation doubles spend, the difficulty becomes exponentially higher.

In short, there's no GUI 'test a double spend' client that I'm aware of.

YOU ARE QUOTING THE WRONG PERSON.

I think you were trying to talk to "twister" so please next time quote the guy who you are talking to  :D

oops sorry dude want me to delete it?

Danny thank you for such a detailed answer. You are right about the risk with all forms of payment. I am so risk adverse sometimes, I get a little fixated on the potential drawbacks of something... but I guess it is better to cover all the possibilities!

Thank you everyone else for your posts also.

To take all the answers into account, I guess there will always be a small risk - but with the right procedures it will never be more than you would have with any other form of payment.

Cheers everyone!

Plan B: Offchain wallets are generally aren't safe. You would have to trust the operator to store your coins in the safest way. There is a risk of the operator running away. One of the biggest scam is inputs.io. They appeared to be quite trusted to majority of the Bitcoin community. In the end, they got "hacked" and 4100BTC were lost. Also, the shop owner must be sure that the operator will not block off their payment and there is no way to prove that the user had actual coins and coins weren't created out of the thin air.
Plan C: This would be like a debit and credit card. This again, requires trust. It is a hassle to maintain so many cards and it would cost some money to issue the cards. This would also cause the centralisation of coins.

As others have said, accepting 0 conf transactions is secure enough. There are less risk associated with it now if precautions are taken.

Well it can be very simple, once the buyer sees the coins in his wallet, even if it is pending confirmations, then that should serve the purpose. Or best way is to have wallet addresses from all the service providers. Like a shop-owner can receive bitcoins in his localbitcoins.com address if his client has localbitcoins address. Then it will be very fast as there will be internal transaction.

I think a system would have to be developed to make the process faster. What really can be done is to actually have a card-swapping type of system. User will have to enter his credentials in a machine and enter the payment amount. Then after authorization, shop owner can collect his payments from coinbase, localbitcoins or any platform. In short, coinbase, localbitcoins will actually work as a bank and can have small fees for their services.

That would be pretty complicating. The whole point of decentralized currency is that it is decentralized. If we bring in card swapping, or any other kind of banking stuff, then how will it remain decentralized. It will ultimately become a controlled currency.

Credit cards take 2-30 days to sort out. Users seem to not know this, but businesses know it well. So bitcoin takes an average of 10mins. vs. a week with credit, and it costs the business 3% for
the card.  Shops do better with bitcoin.

Exactly. I mean the card swapping type of function can be implemented in a decentralized way. Then there will be more service providers like coinbase, etc. All they would have to do is to debit from users account and credit it to the shop-owners accounts.

Once the money is sent its as good as received. How is someone going to manage to double spend? Run around the corner and try send the same money again? Why are you not asking the same questions about shops and credit cards? The money can always get chargebacked something like up to six months later so are you worried about that?

other than that, the whole point of Bitcoin is to be as anonymous as possible. if a centralised authority control your money, it can potentially track you spendings too.
the owner can always proof that you were the one who purchased by showing the authority their cctv footage. also, the ID aren't needed to create a Bitcoin address.

Ok but we are talking about shopping at grocery stores with this "bitcoin debit card" or "offchain payment provider" type thing.

I`m sure nobody cares if you buy a chips and a coke, there are atleast 50 people seeing you buy it in the shop so i`m sure privacy is not important there.

Well of course if you were to buy some intimate stuff (sex toys, medicine or  intimate objects) then thats another scenario, and privacy is important there.

But so far from shopping groceries or other public objects, i dont really care, and neither should you.

As my online shopping experience, some sites requires no confirmation to the transaction. So since the tx appears on the mempool almost instantly after broadcasted, and it will detect that if it is a double spend (if not, then it is a real tx). So some shops may do this.

Most companies would have to comply with the local law to operate there. If they happen to operate in a country with strict KYC policies, they would be required to have the customer's documents verified. This can be problematic since NSA are interested in spying on people. Isn't it so much easier spying them by the payment processor?

many services like bitpay do it instantly not even a confirmation is required

Yup this is pretty spot on.

I help several friends with their business on the back end of stuff if they need help. I rather have the transaction also thats non-reversable as well since the product can be in a un sellable condition for them.

there already are shops that don't require you to wait for confirmations. you get what you buy instantly. but i don't think they will do the same if amount is higher than $20-$30

damn ,your good . real good . damn I was thinking that . lol Right on!!!!!

if we can have a very good regulation and services that take all the risk about a possible double spend when you perform a transaction, then there will be shops in the future who are willing to accept $200 worth of a transaction without any confirmation

the problem is having an authority that deal with this kind of stuff, a third party that connect the user to a shop, like coinbase, but coinbase still require confirmations, so a better thing than that

p.s. ah yeah bitpay, i forgot about that, tnx for reminding me

Bitpay. I have used them on various site and they don't seem to require any confirmations if the owner chooses to. If you wait for a few minutes and check for competing transactions, propagation and fees, I don't see why would you have much risk when accepting such transactions. The best way is to ensure that the transactions is in the mempool of the top pools and they have reasonable priority.

I think they just take the risk. The same is true for small credit card transactions. For example at McDonald's when you swipe your card there is no signature or pin number used because the chance of fraud and the stakes are so small. No criminal would orchestrate a fraudulent purchase of a hamburger, it would not be worth it. A double spend of bitcoin would require a lot of knowledge, set-up, and the chances of success would be small. It's just not a realistic threat.
Sure, if I were buying a car I would wait to see a few confirmations, but not for a sub-$100 purchase.

Payments take long? They're instant. Sometimes I think the people who ask this question have never actually sent bitcoins themselves.

Even though double spending risk at no confirmation is little to none, the risk is still there. People don't understand how Bitcoin works and draw the conclusion that any no confirmation transaction have the risk of double spending. However, it is worth noting that in the event of 51% attack, transactions can be reversed relatively easily. It can be done but lots of computing power is needed to initiate such attacks. Many other methods still exist for transactions with no confirmations, all the seller have to do is to take precautionary measures to ensure the risk is minimal.

Transactions are broadcast on the blockchain instantly. Payments only take a while to process if confirmations are required.

well yeah but if they start making order and the confirmation arrives only after 60 minutes people can double spend bitcoins cant they?

Technically yes but practically, it's really hard. Once the transaction gets proporgated to a huge number of nodes and miners, they will reject any other transactions spending from the same input. Lest the miner uses replace by fee patch, once it has been relayed across the network and a reasonable fee included, miners would reject the next transaction spending the next input. To my knowledge, no miner with good amount of hashpower use that patch.

For smaller transaction I think shops won't mind and they will let you walk out with goods without any confirmations if your transaction has the right amount of fee and it is of 'High Priority' but for larger ones the shops might require you to wait for at-least one confirmation. Also you have to understand that shops have cameras and if someone does this, i.e. pays with bitcoin, walks out and perform a double spend, it will be considered stealing and if the shop owner complaints you will get charged, performing a double spend whilst shopping online anonymously is one thing but doing it face to face can have consequences.

But I think we're thinking too far here, Bitcoin is more suited for online transactions and this is why we need more online shops to start accepting bitcoin first because where I live I don't know any stores that accept bitcoins for face to face transactions.

What can you actually do with the footage, that's one thing. You can't go to the police and say this person stole something, they don't know which person you are talking about. If the double spend is successful, you wouldn't have any proof that double spend was conducted since the transaction will be dropped from the mempool.  In some places, Bitcoin isn't offically recognized as a currency and that is another thing.

The problem with that theory arises when someone "forgets" to attach a fee to the tx.    Try sending a no fee tx these days.   With the current tx volume on the network, it is damn near impossible to send a tx without fee.  It will get returned to sender within a day or so.

transactions without fee fastest I've ever done takes about 6 hours. but now when I try it again,
it almost becomes impossible.

If you both are so sure that a transaction without a fee will be returned to you, then I'd like to propose a challenge to you.  Let's see you put your money where your words are:

I'll provide you a bitcoin address of mine.  You send 1 BTC to that address without a fee.  Then double spend that same input back to an address that you control (or wait for it to be "returned to sender").

If you can keep the transaction from being confirmed to my address, I'll send you an extra bitcoin as a reward for your effort.

If you fail to keep the transaction from being confirmed to my address, then I get to keep the bitcoin.

So, if I'm right, I gain 1 BTC from you.  If you're right, you get your bitcoin back and you gain 1 BTC from me.

Should be the easiest $250 you'll ever make.  Right?

I did a transaction once without a fee it took me 1-2 days to confirm, it was pretty annoying, but then again a 0.0001 fee is not the end of the world.