Bitcoin Forum

A minutes ago an idea came to my mind and I hope it will not be wrong.

Most of the people say that buying with bitcoins at local shops will be bothering as they will have to wait for longer at the local shop for the confirmation of their payment in bitcoin to the shop/store. But one thing is in my mind that if a person pay a suitable miner fee for a transaction then that transaction cannot be cancelled. So if a person will pay in front of the shopkeeper and the shopkeeper will know that the person have paid a suitable fees then he will provide the good at zero confirmation (without waiting for any confirmation).

What do you think about that idea?

It's true, Bitcoin transactions with a 0.0002 fee are confirmed very quickly. And even credit card payments can be reversed many days later. So even though the transaction is unconfirmed, it's still received "instantly".

I am not sure about how it works but what aboutnif a double spend happens ?
I habe only heard of double spending I dont know how its done.

I agree there is still a chance of a double spend attack even if you paid the right tx fee.  Double spend is done by sending another transaction that has higher fee and be confirmed faster than the previous transaction.  I think having Bitcoin notes or physical bitcoin money can solve this but there are more risk involved on that and need a centralized system to make sure that the private key of each physical coin is not compromised.

Just ponder if you have to make up to 10 transactions per day how much you would paid on those transaction? and besides can everyone do that? then mining will be more profitable then

It wouldn't be hard to backup your wallet, make the payment, then restore the backup and add a huge miners fee and empty it.

I'm working on a project to make transactions faster when using Bitcoin in shops. It's a long way off and probably not to every-bodys taste though.

Try and sell that to the average merchant. Wont work.

It could work for online, seller can package product ready to ship, but in that case they'd just wait for confirmations anyway.

I agree with your opinion, lack of double spend transaction

Read this. https://en.bitcoin.it/wiki/Double-spending

The confirmation or validation method was resolving it.

A big chance about the double spending will happen, at least if the seller was accepting a confirmation and he still goes to get a chance about the double spending.

read the hypothesis.
https://bitcointalk.org/index.php?topic=36788.msg463391#msg463391

Putting the higher fees is not the excellent way. You weren't thinking if the spam transaction will be happening?

The Vendor will be a fool to trust anything, but seeing the actual confirmations on his own wallet.
Other Screens can be faked. Most Vendors won't have the expertise to know if they are being tricked or not.


 8)

No vendor is going to let you leave until they actually have the money in their wallet, which means waiting until the transaction has at least a few confirmations.
If bitcoin can come up with some solution for this, it would make it possible to spend in real time in stores.

Unfortunately, for now, this means relying on third-party solutions.
However, even an established company providing escrow by means of prepaid credit cards might be enough to persuade shop owners to accept the payments.

Yes it is true that for merchants card payments have higher risk of chargebacks but with only one confirmation bitcoin payments is safer for merchants. Fee is not fixed and 0.0002 may be only enough for transaction with one input and two output.

Everytime it won't be successful. At times delay in confirmation happens. Merchants were safe, once its send it gets received. Conformations will be pending which is not an issue. These days people haven't got as many shops to make transactions for daily needs.

Just pay 30 cents and your transaction will confirm in less than 5 minutes or pay more like $0.5 to get a confirmation under 3 minutes.
With paypal or credit cards you are usually paying more fees than above and even if you'll end up paying the same fees you know that you could always mine altcoins exchange to bitcoin and there you have printed your own money as well there are not stupid limitations on bitcoin.

There is also a way in which the merchants could be linked to nodes directly for transactions to be broadcast in blockchain immediately, though I'm not quite sure how do the nodes receive transactions and in what orders?

If using bitcoin entails more fees even at slower transaction speeds, that would not be popular with the masses. I am doing our grocery shopping on a weekly basis and I just use my debit card, simply because it is fast, hassle free and you get to earn some points on the side. That is another issue that bitcoin developers will have to address if they wish to make bitcoin the currency of choice of future generations.

You are confused.  :P
Blocks being found is not dependent on the fee you pay, that depends on when the miners find a block,
and the rated block speed is every 10 minutes. Higher fees just means the miner will add your transaction to the next available block when they find it.
On Average a block will be found ~ 10 minutes, so any fee that gets a transaction included in one in 10 minutes, there is no reason to pay a higher fee than that.


 8)

Little Conspiracy Secret the original creators of BTC , Never intended it to be used for everyday purchases.
It was to be used as a way for Banks & Financial institutions to transfer money between each other, (so they can fire the security companies that transfer cash & gold between them), they have always intended for the little guy to have to use bank/credit cards/checks (which they control).
Only difference instead of Fiat, they will fraction reserve BTC on you.  :P
That is why they made it sooo slooow.

 8)

We had a meetup at a pizza joint in Vegas on Saturday where the check was paid via bitcoins. Upon paying, we were gone sans waiting for any confirmations. Ergo, a nonissue, akin to not having to wait around a vendor's shop for months till he's satisfied that you're not going to reverse the credit card payment. Defense mechanisms are in place and where even the rare nefarious actor that's able to game the cryptocurrency-payment system are chalked up as the cost of doing business. I can easily state that more money is lost in any B&M business via employee thief and incompetence at the till than cc chargebacks and rogue crypto payments combined, the [estimated] dollars lost making up a percentage of the product or service's price point.

I doubt it will work, there is a reason for confirmation for transactions, accepting payment of unconfirmation transactions is very risky and if the trade goes south for the shop, he may likely not accept BTC again. At least one confirmation is required for any transaction. What will need is faster transaction and I know we will reach that soon

There definitely is a chance that people can double spend. The amount of gees that is used doesn't really change that. Having higher fees doesn't automatically get your transaction into a block for confirmation.
It definitely would make mining a lot more profitable that it currently is and maybe more people would start to invest in Bitcoin mining

paying normal or even fees in a transaction doesn't make it impossible to double spend, in other words the bold part is wrong. technically when  a bitcoin transaction is not yet confirmed it can be double spent, and even you have to see at least 3 confirmation in normal state of the network to be sure about the receiving of the transaction.

but none of these mean a shop can not trust customers with 0 fees. you just check (automatically of course) that the tx has enough fee and some other criteria to make a risk assessment. it is similar to accepting a check and trusting the person to have money in it.

Block re-orgs that long rarely happens. As long as you continually broadcast the transaction, the transaction would be hard to double spend.

Bitpay offers this, if the merchant wants. I believe that most shops do not require any confirmations before accepting the payment. It's a different story for online merchants however.

As long as they pay a reasonable fee, mining pools are willing to accept it, Opt-in RBF not enabled etc, and the transaction is of a small value, merchants wouldn't have any reasons to require a confirmation if they want their customer.

that is correct. and that is why i said in normal state of the bitcoin network. even 1 confirmation is ok if you consider the number of orphaned blocks that happen in a week. the chances are so slim.
but i mostly had this in mind: https://bitcoin.org/en/alert/2015-07-04-spv-mining

This is new to me. I have never heard about this issue before because I rarely pay for a high transaction fee. But how can people differentiate them from double-spending? Because I have seen many double spending with big amount of fee and fraud may use them to trick those sellers

Use a full node and always upgrade your Bitcoin Core to the newest version. If you're using an SPV client, use a upgraded full node to connect to.

Doing this will prevent your client from accepting any invalid blocks.

probably that's right. when the vendors do not really understand the idea OP mentioned, or in other words the confirmation system, they maybe not accept this way. just make sure first the vendor understand OP's idea before do such thing.

however, in order to avoid double spending too, I think we still need the other idea.

Realistically speaking, how many people would cheat and steal from their local grocery store by exploiting double spending?
Because I don't think it will be that much of a problem at all. There is impossible to collect data about double spending done in brick and mortar shops, unfortunately.

Instant, trustable payments require a trusted 3rd party to handle both wallets and they can guarantee the funds are there and give an instant yes/no.

physical bitcoin money? then you better just used a Fiat instead. There is no point in having a physical bitcoin money in my  serious opinion lol. If the shop can't receive the bitcoin then simply don't give the product that the customer ordered yet(it would atleast take a customer minutes to double spend that you are saying)

the confirmation system is not about speed of confirmation and fees, it is about showing the other side of the TX that you are not spoofing the system and the blockchain.  if i am faking a TX, then who cares how high of a fee i "pay" because there is no fee ever leaving my hands

You must realize if the system has applied in bitcoin already preventing the double spending.
At least we are too far from the double spending with applying some confirmation in our transaction.

It's not a bad idea, and it will probably have a bit more of a benefit for shops since they lose less money on credit card transactions compared to something like Bitcoin (dollars versus tens of cents).

I don't believe double-spending is a huge issue within the Bitcoin economy yet, but it could find more prevalence in the event we go to something like this. Confirmations still take about 10 minutes.

I think 3rd party is need to manage the risk to avoid double spending, but also I think need more time to confirm the transaction. Use multisig maybe?

Then to proof the transaction have been made, the customer just need to show txid, then list to merchant queue, done.

yes its a good idea to pay in front of the shopkeeper but the problem is now a day its normal to see 40000 to 60000 unconfirmed transactions and my friends had encountered reverse payment that is when the transaction is left out of confirmation then many used to get reversed so if that happens then shopkeeper would suffer huge loss as the product would go for free.

Okay, then what is the advantage for the shop owner? it feel a bit risky when you haven't received the money in your hand, if I am the shop owner I will prefer to take cash rather than bitcoin, and then price instability also one of the shop owner problem, for the store that got a slim profit it will be risky to sell the things using bitcoin, because when the price is drop the owner will lost the profit

Bitcoin will never be viable for instant shopping payments on-chain, it will be resolved by the 2nd layer solutions such as lightning network, so by all means yes, buy and stop worrying about it, it all will get solved eventually. Not that it is a problem nowadays since no one except 4 geeks use it to pay IRL.

You know as a merchant, you should definitely think about accepting tx's with zero confirmations, if the tx is of very little value...say a

cup of coffee or a donut. The chance that 1000's of people are going to go through all the trouble to double spend for a cup of coffee are

ridiculous. We have a zero confirmation rule in our local pub.... They accept zero confirmation tx's, but they write down our Bitcoin

address against our names and telephone numbers and then they phone you, if the tx's are not going through. {This is only for the

members of our group, because we introduced them to Bitcoin... so this will not work for strangers}  ::) 

The confirmation is a thing of concern and not only at local shops but even at individual wallets in my own a transaction has entered my wallet for hours now but its still showing zero confirmation out of three. Good for me because I know transactions can be delayed even with the right amount paid as transaction fee but for a local store who sells in cash is now be encourage to use bitcoin I am sure patience is not a quality that will be very much available in this case...

I think it is a bit risky to accept payments that are not yet confirmed, i would wait for at least 1 confirmation then deliver the service or stuff to the client.

I have seen that BitPay has something that calculates if the transaction can be confirmed or it will just stay in blockchain for 2 days and will be ignored.

as OP said if you pay a valid transaction fee for the payment the chance of delay or being canceled will 90% reduce. so infront of the shopkeeper sending payment with a good transaction fee should help in buying stuffs offline.

Sometimes it's not about the transaction fees, even if you have enough fees the transaction can not be included in block.

Why? Because there might be some other transactions that are linked to this tx and are unconfirmed so the delay can be up to 2 days or never will be confirmed.

Such issues were there as the above mate mentioned. This need to be eliminated so to make more merchants accept bitcoin. In recent days Japan is the one which has got increased number of merchants as well expected another 20000 merchants to accept bitcoin as well other altcoins that are popular in the digital currency network.

Look, there should be a service that can estimate if the transaction can be confirmed within an hour or few.

Otherwise manual checking is not always safe and that's why merchants are waiting and hesitating to accept bitcoin payments.

Transactions with proper fees are confirmed quickly indeed but the various types of double spend attacks leave store owners without any choice when it comes to accepting bitcoin transactions other than to wait. This doesn't exactly make POS with bitcoin convenient for either party. 

It's always about the amounts. If the amount to be stolen worth the hassle, somebody will do that.
Some are honest, some are not. Some are in need, some not. And some will do it just because they can.
If you buy a bread a some bananas, it's not even worth to pay in BTC because of the tx fee. But if you buy 100$ worth, hmm.. a double spend may look interesting...
Edit: you have to be quick, but it should cost you under 5$

There is just one problem with that. You will be paying more than what you are buying.
You bought a chocolate in a nearby convenience store for a dollar in bitcoin price. The miners fee to make ir faster is a dollar and 50 cents.
Ergh that wont work my friend.

You are right in your opinion but it is not the problem why shops doesn't accept bitcoin. The main reason is that some transaction are being confirmed twenty four hours later and that would affect some small shops since they cannot buy during closing to replenish their stocks. It's feasible to merchants with capital but to small vendors it is very problematic.

Well thinking , but here I want to tell you something different .
First of all take example of transaction made by me . I made transaction of 0.01 btc in emergency with 0.001btc transaction charge To my friend  , at that time.of transaction unconfirmation problem.was going on but after 6 hours my transaction reverse , so how can you tell that bitcoin transaction with high transaction charge is much better and no chances of reverse .
Secondly I have idea for this , To make a wallet of bitcoin to make deals directly without confirmation ( because every transaction will be written data of single wallet but multiple user And I think this is the same idea of bitcoin wallet of zebpay bitcoin wallet , since I never tried but but mist of the friends told me that zebpay to zebpay transaction needs no confirmation and without charge ).

Not really, once my friend paid me 0.5 btc with 0.0009 btc fee, but I waited 15 hours to get 1 confirmation, so the confirmation time sometimes not short any more, maybe there were too many transactions in the same time?  :-\

Bitcoin is created to destroy any Internet money's that make a dominate for Internet payment transactions with high fee, many rules, requiring identity, bank account, long time, and any others rule.
Bitcoin is simple, cheap, instant, and easy. If sending bitcoin to an address need more than an hour, it is not an instant payment.

Bitcoin is not cheap if we are talking about local transactions. For example, I can pay any merchant in my city for his services or products with 0 fees. Why do I need Bitcoin if I'm using instant payments method with 0 fees? Another thing if we are considering international transactions. Bitcoin is considerably cheap but also it depends where do I want to transfer. In EU I pay 0.12-1 EUR per transaction. So, it is also cheap. Payment to USA is about 3 EUR. Also not very expansive. What we are left? Speed. Bitcoin transactions arrive the same day. But recipient needs to cash out from BTC to his local fiat currency. It is very disturbing. Cashing out Bitcoins also means fees, volatility etc. It means if I sent 1000 USD to Ben in New York he, actually, gets less. That is not business model for digital cash. I see the only niche for Bitcoin - banking for undocumented and unbanked. Because in developed countries we have all access to financial system and I still can use the most secure and anonymous transactions with cash.  

what if the transaction gets reversed after waiting for confirmation. which I am suffering since last night. Paid 0.0001 fees also but still, My transaction is on pending and not even a single confirmation was done. and many of my friends had encountered the problem of reverse transaction if that happen then really the shopkeeper will see nightmare

High fees would process the transaction quickly but since many items are available at the price of bitcoin fees then why would someone use bitcoin to pay (I mean, if he is getting the goods at a price of transaction fees then he will go for cash instead). Paying high fees is suitable for big purchases but I am unable to understand that how is it beneficial for smaller priced commodities?

No bitcoin is not going to destroy the internet and online payment system but its just will add simplicity and add an option for those users who cant afford bank and online payment through other mode of payment. like me who use to buy domains with bitcoin because I don't have a credit card and debit card of VISA so its better for to pay with bitcoin. it's how we look and use certain technology that makes its quality good or bad.