Smart Contract helps when shopping!?

[joker_josue]

It has already been discussed here on the forum, about privacy when buying/selling products with bitcoin. Many raise the issue that when paying for a product in BTC and giving delivery data, the person is exposed and loses their privacy. In a way I understand that, but over time, I've been trying to think of ideas to minimize this issue. And this is one more...

The idea would be a smart contract, where the buyer chose and paid for the product. After this procedure, the seller only received the purchase order, not knowing the transaction involved in that purchase. And in the case here of the forum, not even which user was.

Ok, the idea that person X has bitcoin will always be in the air, even if this is not true. But, for that, it is enough for the smart contract to be prepared to receive several types of coins and even fiat. Thus, the buyer never knew which payment method was used by that customer, becoming a normal purchase in any common online store.

Do I think this idea made sense?



^{I opened this topic here, because I was in doubt where it would be better. If any moderators find it appropriate to move to another board, I appreciate it.}

[bitmover]

The idea would be a smart contract, where the buyer chose and paid for the product. After this procedure, the seller only received the purchase order, not knowing the transaction involved in that purchase. And in the case here of the forum, not even which user was.

Such smartcontracts are usually not available in the bitcoin network, or they are too expensive to implement and use.

usually, smartcontracts are implemented in altcoins such as ethereum.

I believe there are better ways to achieve privacy using bitcoin.

Many raise the issue that when paying for a product in BTC and giving delivery data, the person is exposed and loses their privacy. In a way I understand that, but over time, I've been trying to think of ideas to minimize this issue. And this is one more...

I don't think the user is exposed when paying.

Professional payment processors make 1 address per customer, so the seller has its privacy.

On the other hand, the customer will just expose one or a few inputs (depending on how much he is spending).

If the customer cares about his privacy, he should carefully choose which output to spend. For example, if you have your life savings in one input (such as 2 BTC, for example) you won't spend that when buying a $20 gift card. You should choose a small input.

Also, if all your inputs are in the same address with your life savings, you should use a mixer and split them and smaller values to be able to use them separately.

Edit: Let´s remember that you are much more exposed when paying with credit cards. The seller receive all your personal data, document number, account number, etc...

[NotATether]

The idea would be a smart contract, where the buyer chose and paid for the product. After this procedure, the seller only received the purchase order, not knowing the transaction involved in that purchase. And in the case here of the forum, not even which user was.

Such smartcontracts are usually not available in the bitcoin network, or they are too expensive to implement and use.

usually, smartcontracts are implemented in altcoins such as ethereum.

Smart contracts are not very useful for shopping, unless the shopping application is also a Dapp. But I assume we are talking about shopping from normal websites, then no, the payment processor used by the website has no idea how to utilize the smart contract to get only the purchase order. The best they can do is link up with a web3 wallet to pay directly with it, but a contract by itself would not work because it would be quite expensive to use.

[Coyster]

Do I think this idea made sense?

I don't think this can be implemented for this purpose. The buyer doesn't even need to use smart contracts to achieve privacy, the buyer should avoid reusing addresses when making payments for shopping.

When the buyer makes the payment, all the seller is privy to is their address, as well as linking the inputs and outputs on the address, thus if the buyer avoids reusing addresses as well as using CoinJoin or mixers for obscurity, then they will achieve a high level of privacy. If the buyer also wants to make the payment from an address with too many inputs, they can use Coin control to select the address and UTXO they want to spend, these are better ways to achieve privacy.

[jrrsparkles]

Do I think this idea made sense?

I don't think this can be implemented for this purpose. The buyer doesn't even need to use smart contracts to achieve privacy, the buyer should avoid reusing addresses when making payments for shopping.

When the buyer makes the payment, all the seller is privy to is their address, as well as linking the inputs and outputs on the address, thus if the buyer avoids reusing addresses as well as using CoinJoin or mixers for obscurity, then they will achieve a high level of privacy. If the buyer also wants to make the payment from an address with too many inputs, they can use Coin control to select the address and UTXO they want to spend, these are better ways to achieve privacy.

AFAIK, OP is trying to find a solution that can be used by everyone on the daily basis which is good but as mentioned above bitcoin network created intentionally with limited scripting language to prevent vulnerabilities and exploits that could compromise the network. So the solution maybe available on L2 layer which enables to implement more complex smart contracts without compromising the network securities.

[vv181]

Many raise the issue that when paying for a product in BTC and giving delivery data, the person is exposed and loses their privacy.
~
Do I think this idea made sense?

Well, you can still actually links the transaction to the buyer due to the amount being exposed. Simply watch the particular contract at some point in time when a seller received their Purchase Order, depending on how it will be implemented, I think it will still fall to the problem that I stated. But this assumes it only uses bitcoin.

Ok, the idea that person X has bitcoin will always be in the air, even if this is not true. But, for that, it is enough for the smart contract to be prepared to receive several types of coins and even fiat. Thus, the buyer never knew which payment method was used by that customer, becoming a normal purchase in any common online store.

That would require a complex contract, it has the requirements of interoperability with each coins chain and FIAT payment gateway system.

I don't think the issue you raise is worth and urgent enough to be solved merely by this smart contract idea.

[joker_josue]

Thank you for your feedback, it allowed me to have a more comprehensive idea about this issue. And really this is not the best solution.

Either way, I think it's good to make use of these ideas, as it allows us to analyze various scenarios and various probabilities. With this analysis, we can find a viable model.

I think the biggest issue is actually communicating our address. This is the element that I still haven't been able to come up with - that at least makes sense to me, so as to resolve this point.

[Upgrade00]

The idea would be a smart contract, where the buyer chose and paid for the product. After this procedure, the seller only received the purchase order, not knowing the transaction involved in that purchase. And in the case here of the forum, not even which user was.

The seller needs to receive the payment and if the buyer pays in BTC the seller will receive it in BTC typically.
The seller will know that buyer A does not want to reveal their payment methods, meaning they will likely be using a different one from the regular fiat transactions. This will pique the interest of the seller if they had dishonest intentions and they now have the address of the buyer.

Thus, the buyer never knew which payment method was used by that customer, becoming a normal purchase in any common online store.

The buyer will be sure that they did not use a centralized means of payment depending on what means they receive the final payment through.

[Mr.right85]

Do I think this idea made sense?

I didn't really grab all that but, the seller who happens to be the one end of this set up or preparation as I reason it might not be very choosy on targets as per person or coins (again, there is only a handful if coins that have proven valuable and could be readily accepted by merchants for payments should you find one. Most of them would  that which could be paired with bitcoin).

Hence, the merchant with malicious intentions could build his set up not to be choosy on a target and about the price range of products sold and in the event that, a buyer plays right into one, the damage would still be done.

Don't know how much sense this makes but, my thoughts though.

[hatshepsut93]

Smart contract is just a public address, if someone ordered a pizza at 15:33, you can look at incoming transactions around that time and narrow down the potential addresses of the customer.

In Bitcoin, privacy is the responsibility of the user. If they want it, they should mix their coins and practice smart coin control.

[BlackBoss_]

Such smartcontracts are usually not available in the bitcoin network, or they are too expensive to implement and use.

usually, smartcontracts are implemented in altcoins such as ethereum.

Smart contracts take into account the number of code lines, its complexity. The more complicated a smart contract is, a bigger size it is and users will have to pay more transaction fees.

I don't know Vitalik is smart when he included it in Ethereum smart contract because I saw it on my side like this. Developers have to balance between their codes and user acceptance to use their smart contracts for interactions. If they include so much into their smart contract code, users will have to bear much expensive fee which will be like barriers for acquiring new users for a platform.

To deal with it, developers have to keep their smart contracts as simplest as possible and at the same time, still maintain its functionality for users. I am unsure when they use that approach, their smart contracts will still be smart or become more stupid and more vulnerable and easily exploited by hackers.