安全与密码学2020ifca.ai
Satoshi 不知道的事
What Satoshi Did Not Know (2015)
进阶 · 约 30 分钟读完前置知识：比特币协议基础、PoW 共识、货币经济学
导读
这篇论文以“中本聪不知道什么”为题，从后来的发展回看比特币早期设计中未被预见或未被充分讨论的假设与局限。它涉及的核心问题包括比特币的去中心化承诺、挖矿与共识机制在现实中的演化，以及它作为货币/支付系统的定位。具体论证需以原文为准。
HN 关注点：HN 读者围绕比特币是否真的去中心化、ASIC 挖矿导致的集中化，以及它能否兑现电子现金承诺展开争论，并顺带讨论替代币和监管/信任问题。
HN 评论精选
这几条评论里：支持 2 补充 2
支持ASIC 挖矿使“一CPU一票”失效，比特币去中心化被夸大。
事后看，中本聪最大的未预见之处，是“一 CPU 一票”这个想法本身有缺陷：它被自己的成功所害，因为出现了挖矿 ASIC。其后果是，比特币及相关加密货币其实并不像宣称的那样去中心化。很有意思的是，一旦牵扯足够多的钱，事情似乎总会走向集中化，哪怕工程师曾认真设法避免（互联网也是如此）。
svara查看英文原文
With the benefit of hindsight, the biggest thing Satoshi didn't know (or didn't foresee) was that the idea of "one CPU, one vote" was flawed, a victim of its own success, because of mining ASICS. A consequence of that is that bitcoin and related cryptocurrencies really aren't as decentralized as claimed. It's fascinating how things just seem to have a way of becoming centralized once enough money is involved, even when engineers thought hard about how to avoid that (see also: the internet).
补充Nano 用每账户独立链和 ORV 免挖矿，试图解决比特币的吞吐、费用与集中化问题。
Colin Lemahieu 创建 Nano 来解决比特币的许多问题：每个账户有自己的区块链，而不是所有交易共用一条链。结果 Nano 交易不到 1 秒完全确认、无手续费，测试网达到每秒 1465 次确认；不挖矿，因此环保，投票用 ORV（open representative voting），类似委托权益证明但无需质押锁币，更像流动民主：把投票权重委托给代表并可随时更换。因为没有挖矿费，缺少集中化激励，随着采用增加，投票权重预计会更分散。从技术上看 Nano 很惊人。
onelastjob查看英文原文
Colin Lemahieu set out to solve at lot of the problems that Bitcoin suffers from by creating Nano (nano.org). He did this by having each account have its own blockchain, rather than using one blockchain for all transactions. The result is Nano transactions take under 1 second (fully confirmed) and there is no fee for transactions. It's also scalable with 1465 confirmations per second (aka transactions) reached on the test net the other day. There is no mining involved, so Nano is environmentally friend and voting is done using a system called ORV (open representative voting) which is similar to delegated proof of stake, but doesn't require actually staking and risking coins. Instead it is more like a liquid democracy system, where you delegate your voting weight to a representative you select and can change at any time. Because there are no mining fees, there is no incentive for centralization and for this reason it is expected that the Nano voting weight will become more distributed and decentralized over time as adoption increases. From a tech perspective, Nano really is amazing.
支持比特币更像数字黄金而非电子现金，其支付愿景落空。
我认为中本聪不知道比特币不会成为交易媒介，而会停留在“数字黄金”。比特币无法兑现其作为电子现金的初衷，这是比特币信徒最难理解的一点；他们以为币价高就能让它变成交易媒介，但我觉得这是中本聪的虚假承诺。加密货币普及的最大障碍是交易媒介，多数投资者只是在玩 DeFi 之类的热词。
dnprock查看英文原文
I think Satoshi didn't know that Bitcoin would not be a medium of exchange. It will remain digital gold. Bitcoin cannot fulfill its original promise to be electronic cash. This is the hardest hurdle for bitcoiners to understand. They think that sky high value of Bitcoin would transform it into a medium of exchange. But I think it's a false promise from Satoshi. https://bitflate.org/post/2019/11/24/bitcoin-will-not-be-a-medium-of-exchange.html The biggest hurdle for cryptocurrency adoption is a medium of exchange. Most investors waste their time playing around with buzzwords like DeFi.
补充合法交易已有法律与账本保障，比特币主要适合黑市/避监管；美元实践上已很去中心化。
比特币作为无需信任的交易媒介有用，但现实中的合法贸易本来就包含一定信任和可执行的明示/默示合同。合法交易不需要区块链，因为会计账本是透明的、受法律约束，篡改即违法。例如银行不能无故扣你钱；你账户余额的安全不需要区块链，因为篡改账目是犯罪；你也不需要加密账户（相当于把钱藏在隐蔽处），因为盗窃是犯罪，且银行被抢或倒闭还有 FDIC 在一定额度内保障（问问 2015/2016 年 Bitfinex 用户……）。所以除非你在黑市交易或向合法当局隐匿资金，比特币基本是在寻找问题。美元在实践中是高度去中心化的货币：美联储/财政部可以增减供应，但近年美元价值由其在现实世界中的可用性决定，而不是边际上的中央权威行为。我甚至敢说，如果中央当局开始破坏美元在全球贸易中的价值，它们会先失去对美元的控制……
morpheos137查看英文原文
Bitcoin is useful as a trust-less medium of exchange but in the real world, legitimate trade involves some level of trust and enforceability of implicit or explicit contracts. Nobody needs a blockchain for legitimate transactions because there is the accounting ledger which is transparent to the law and whose falsification constitutes an illegal act. For example your bank can not deduct money from your account without cause. You do not need a blockchain for the value stored in your account to be secure because falsification of ledger balances is a crime. You don't need to encrypt the account (equivalent to hiding money in an obscure place) because stealing is a crime and if bank robbery or failure happens you have the FDIC to ensure your balance to a certain degree (ask users of Bitfinex circa 2015 or 2016 about this...) Thus Bitcoin is largely a solution in search of a problem unless you are dealing in a black market or trying to hide money from legitimate authorities for some other reason. The dollar is a highly decentralised currency in actual practice. Yes, the federal reserve or treasury can increase or decrease supply of dollars but in practice in recent years the value of a dollar is set by its usability in the real world not the actions of a central authority at the margins. In fact I would venture to say that if the central authorities started to undermine the value of the dollar for global commerce the central authorities would lose their power over the dollar before the dollar lost its value. Many more countries than the USA use dollars. In fact the vast majority of physical dollars, if not dollar balances exist outside of US jurisdiction. The only way that the dollar can and will be dethroned is if some other currency becomes widely used in commerce. That certainly wont be Bitcoin but it could be another digital currency like maybe Ripple. Bitcoin is not very useable in actual commerce. The processing time of transactions is tremendous, and the deflationary and volatile nature of the currency makes it an unsuitable store of value or unit of account. There is no reason to expect in the future bitcoin will stabilise. Its price is set by exchange speculation and a decreasing rate of new coin supply. Unless commerce overtakes exchange speculation as the price setting mechanism for bitcoin it wont be very useable for legitmate commerce.
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