It is very difficult to double spend bitcoin on the misleading message "say no"

BitcoinBCH, a company focused on Bitcoin Cash (BCH), recently released a video that may mislead users into thinking that Bitcoin's double spend can be easily achieved.

11297122555_5f494f2e5c_b (Image source: flickr )

On December 18th, Hayden Otto, CEO of BitcoinBCH, posted a video on YouTube showing how TravelByBit's Point of Sale (PoS) wallet misleads merchants into accepting unconfirmed Bitcoin transactions . To solve this problem, Hayden Otto also subsequently ran HCH, a BCH-based PoS solution.

Break through misleading information

In a recent interview, a representative of TravelByBit said that merchants using its services can prevent such fraud and protect property. The company's founder, Caleb Yeoh, also said that if a large number of users start to exploit their system design vulnerabilities, the company will remove support for Bitcoin and BCH transactions in its PoS solution.

Yeoh acknowledges that it is not realistic for brick-and-mortar merchants to accept on-chain payments because merchants need to compromise between security and convenience. In addition, no one is willing to wait for 10 minutes to confirm the on-chain transaction before getting the goods. Although accepting unconfirmed transactions can cause serious security issues, this is the only way many physical merchants accept payments on the Bitcoin or BCH chain.

Yeoh said that the Lightning Network is a potential solution that can solve the problem of waiting for transaction confirmation time when the physical store uses cryptocurrency to pay. He told Cointelegraph that Lightning Network transactions are also an important part of PoS system payments:

From a retail perspective, more than 47% of bitcoin transactions in Australia over the past 3 months were completed via the Lightning Network.

Otto did not point out in the video released that the unconfirmed transaction is not the final confirmed transaction. Instead, he said that the flaws in the design of the wallet actually originated from the security flaws of Bitcoin, which eventually led to the double spend. Hayden Otto said in the video that merchants should "immediately stop accepting Bitcoin and switch to BCH."

Otoo uses Bitcoin feature RBF for double spend transactions

In the demonstration, Otto first sent extremely low-cost Bitcoin (1sat / byte) to another wallet that he controlled and enabled the replacement-by-fee (RBF) function. Bitcoin users know that for such a low-cost transaction, it usually takes a long time to be confirmed on the Bitcoin blockchain. If the Bitcoin network is heavily congested, the transaction confirmation time may even exceed one day.

RBF is a feature that allows users to submit transactions with higher fees to nodes, thus replacing previously unconfirmed transactions. This feature of Bitcoin has previously sparked criticism from some users as it could increase the cost of unconfirmed transactions.

However, these concerns are unfounded, because unconfirmed transactions can also be double spent without this feature. In 2015, the author of the BitTorrent protocol, Bram Cohen, published a related article that analyzed this issue in depth.

In fact, an unconfirmed transaction is not the final transaction result and should not be accepted as a payment.

Unconfirmed transactions are irreversible, the site that promotes BCH, recently reported that BCH removed the RBF function from its code. The article wrote:

The BCH community believes that zero confirmation transactions are reliable and secure.

After Otto sent the first low-cost transaction (supporting RBF) in the video, he made a Bitcoin payment to a merchant that did not enable RBF. At this time, the merchant's mobile wallet interface displays the symbol of receiving the payment, thereby misleading it to believe that the payment has been received.

Because the wallet user interface shows that the payment is complete, the merchant transferred the product without the transaction being confirmed. Otto then raised the cost of the first transaction to ensure that all funds were transferred to another address he controlled before sending it to the merchant's address.

In this way, Bitcoin was not sent to the merchant, and Otto eventually owned both the commodity and Bitcoin (minus transaction fees).

In the second half of the video, Otto stated that reversing Bitcoin transactions is dangerous. Otto's statement falsely implies that the transaction he conducted has been reversed. In fact, the changed transaction is unconfirmed (it is not the final transaction result), and the agreement will still perform as expected.

Otto also stated in the video that "BCH solves this problem (double spend of unconfirmed transactions)." In response, Yeoh suggested:

No one can stop the BCH miners from replacing transactions. Occasionally, double-spending transactions like 'RBF' occur on the BCH network. It should be noted that RBF is not a protocol consensus feature. It is a node strategy. Any Bitcoin or BCH miner can choose whether to run this feature. It does not affect the reliability of payment.

Yeoh pointed out that the hash distribution gap between Bitcoin and BCH will also affect the security of transactions, and the current situation is more favorable for Bitcoin. In addition, he said that attacks between different cryptocurrency communities can hinder innovation in the field:

I think the community should focus on helping build and expand how different ecosystems adopt each other, rather than focusing on projects that attack each other, it will only affect the development of the cryptocurrency field. People should be free to choose which cryptocurrency to use for trading and to contribute to the ecosystem as builders.

This is not the first time the BCH community has disseminated misleading information. Cointelegraph reported in April last year that was accused of displaying cryptocurrencies in a misleading manner, thereby misleading users to buy BCH instead of Bitcoin.