Published on: 2014-06-19T03:47:17+00:00
Chris Pacia expressed his disapproval of a proposed payment system that requires users to have double the funds they need for a purchase, calling it an "ugly hack." He argues that not everyone will have the extra funds available, making it inconvenient to use the system. However, it was noted that the scheme would not be mandatory, and users could still opt to wait for confirmations or rely on existing trust.Mike Hearn responded to concerns about double spend attacks on Bitcoin, stating that the risk of getting caught and blacklisted makes it unlikely for attackers to attempt such an attack. He acknowledges that a dishonest mining pool could potentially execute a double spend attack for a fee, but this would not be feasible for high-value items due to the need to wait for block confirmation. The concern lies with opportunistic attackers who try to take back a portion of their transaction every time they make a purchase. The number of such opportunists and the hashrate a dishonest pool can attract remains to be seen.Double spending is when a person spends the same digital currency twice, but Bitcoin has been designed to prevent this. Successfully double spending does not result in getting money back, but rather being chased down by a shopkeeper or being blacklisted. The concern arises when one could actually double spend, and the only thing preventing them from doing so is Bitcoin's technology.Chris Pacia suggested an idea for Bitcoin transactions to prevent double spending. The proposed method involves the customer signing a transaction and walking out of the shop with their purchase. They would then immediately sign and broadcast a double-spend transaction with a higher fee. The POS computer would detect the double spend and sound the shoplifting alarm. While some complications exist with this scheme, Pacia believes that the number of people who would attempt this irrational method is lower than those who would shoplift traditionally.Mike Hearn raises a concern about fraudulent double-spending activities in payment networks. He questions the possibility of a customer buying a phone on contract and paying an artificially lower price, then double-spending by paying double the lower price. However, he suggests that nearly all payment systems have the same issue of needing to enforce contracts out-of-band.Bitcoin's relevance should not be compared to a theoretical perfect peer-to-peer system but rather to traditional bank notes and credit cards. While Bitcoin may not be the ideal instant peer-to-peer serialization mechanism, it still holds value and relevance in the current financial landscape. Bitcoin faces challenges in terms of proof of work, but this does not diminish its significance.The proposed scheme to discourage Finney attacks by charging the maximum double spending fee possible does not solve the problem. Chris Pacia prefers the hassle of a green address notary instead. There are also complications with the scheme, such as needing to double balances and what happens if a shop is selling something on contract.A discussion on replace-by-fee and child-pays-for-parent addresses the success rate of double spends. It is suggested that these policies would significantly reduce the risk of double spending. However, there are concerns about sybil attacks and the requirement of online private keys to sign replacements. Enforcing hashing visibility of block contents can help detect double spends and make them beneficial for decentralization.Jorge Timón proposed a solution for 0 confirmation transactions, but Peter Todd conducted an experiment suggesting that double spending frequently works without miners using replace-by-fee. Todd argues that only confirmations are solid evidence that a transaction has reached mining power. Enforcing hasher visibility of the blocks they are mining allows any hasher to detect a double spend.The proposed scheme to discourage Finney attacks does not fully address the issue, and a better solution is suggested. The discussion also explores the concept of 0 confirmation transactions and their feasibility with replace-by-fee policies.
Updated on: 2023-08-01T08:58:18.899247+00:00