【A3】Bitcoin Isnt Broken

No, Bitcoin I sn’t Broken“Bitcoin Is B roken,” proclaimed声明，宣布，公告Ittay Eyal and Emin Gun Sirer, two Cornell康奈尔大学（美国纽约）computer scientists. In Bitcoin’s peer-to-peer process for processing transactions, computers called “miners” compete to竞相做某事solve a difficult mathematical problem, with the winner earning a reward. The researchers analyzed the rules of this process and concluded that it allows a minority 少数的of miners to collude 串通，勾结and gain more than their fair share of the rewards. In the long run从长远来看，终究, they suggest, this colluding minority could seize control of the Bitcoin network, negating否定，取消，使无效the benefits of its decentralized分散式的，分散化的，分散管理的，peer-to-peer architecture 体系结构.This is a clever analysis, but it falls far short of 差得很远，远未能proving that the decentralized cryptocurrency加密电子货币is fatally命中注定的，致命的，无可避免的flawed有缺陷的，有瑕疵的. In reality, the attack they outline is a relatively minor concern次要问题for Bitcoin miners, and shouldn't affect ordinary Bitcoin users at all.Bitcoin’s transaction clearing process operates like a virtual lottery虚拟彩票. Each miner makes a list of recent transactions交易, called a “block”块区, and then tries to solve a difficult mathematical problem that takes that block as an input投入. A correct solution works like a lottery ticket —it’s hard to find but easy to verify 验证，核实once it’s been found. The first miner to find a solution announces it to the rest of the miners to claim the prize. Within a few seconds, the other miners verify the ticket is valid有根据的，有效的, and then the process starts over, with miners creating a new block and trying to solve a new round of the puzzle.In the Cornell researchers’ attack, a minority of少数的evil miners collude in hopes of gaining an unfair advantage over everyone else其他人. Their strategy works like this: When an evil miner finds a winning lottery ticket, it shares it with the other evil miners but not with the rest of the network. The evil miners abandon the current round and start working on the next one. Meanwhile, the rest of the miners continue looking for a solution to the block the evil miners have solved. That gives the evil miners an unfair head start on the new round of the game.Eventually, one of the honest nodes will find a lottery ticket of its own and present it to the rest of the network for validation. The moment that happens, an evil node will present its own winning ticket to the network.Who gets the reward? It’s complicated, but in a nutshell简而言之，简单的说the winning ticket will most likely be the one that the majority of other miners see first. If two miners release tickets nearly simultaneously同时地, then some miners will hear about the honest miner’s ticket first and others will hear about the evil miner’s ticketinstead, making the outcome a tossup.抛硬币决定某事，没准的事To ensure that most nodes hear about the evil nodes' ticket, Eyal and Sirer propose 打算that the evil nodes set up a large number of fake miners whose only job is to listen for honest miners announcing their own tickets and then quickly disseminating 散播，传播the evil miners’ preferred ticket instead. In theory, a large enough network of fake miners should be able to ensure that the evil miners’ lottery ticket gets accepted close to 100 percent of the time. And even without that kind of trickery诡计, the researchers calculate that the colluding miners may be able to get their ticket recognized frequently enough that the strategy earns the colluding miners an unfair profit at the expense of other miners.The upshot结局，结果is that the honest miners waste a lot of their time trying to solve a problem that's already been solved. So the evil miners will win more than their share of the rewards. The researchers argue that honest miners will have a strong incentive动机to join the conspiracy阴谋集团. Over time有朝一日。

经过一段时间后, they say, the conspiracy will grow until it has gained a majority of the network’s computing power计算效率. And at that point在那时，在那个阶段, it will gain the de facto power 否决权to block and even reverse transactions submitted to提交the network.“I think it’s been overblown过分渲染by the media a lot,” says Bitcoin developer Mike Hearn of the paper. He says that Eyal and Sirer “hand-wave away” 没有充分考虑到many of the potential difficulties in carrying out their proposed attack. For example, he says, it would be hard to add a huge number of fake miners to the network without people noticing.Indeed, the biggest problems with their attack are social more than technological. Many Bitcoin miners have organized themselves into “pools” that combine their computing power and share the proceeds收益. The leaders of the major mining pools know each other. And if some miners started trying to corrupt the mining process, they would notice.It’s not hard for honest nodes to take countermeasures反抗手段，对策if they figure out what’s going on and which miners are part s of the conspiracy. If an evil miner and an honest miner both announce a lottery ticket around the same time, the honest nodes can always pick the ticket announced by the honest miner over the evil miner’s ticket.And the Cornell attack would be easy for honest miners to detect. Right now, it’s rare for two miners to announce solutions within seconds of each other. If that started to happen on a regular basis, it would be strong evidence that something fishy可疑的was going on. The more often it happened, the more data they’d have to help them identify who was honest and who was participating in the conspiracy. Honest miningpools could publish lists of their members to help flush out冲掉，排出，驱逐出来the impostor s.骗子，冒名顶替者“People have been coming up with complicated game theory博弈论attacks on the blockchain for quite a long time,” Hearn says. “This one is interesting but it’s not the biggest problem Bitcoin faces by any means.”Key word1.coinbase 比特币钱包2.加密电子货币加密电子货币（Cryptocurrency）3.比特币是经由一种称为“挖矿”的过程产生，参与者通过处理交易验证和记录来获取作为手续费的比特币，或取得新产出的比特币。