An anonymous user mobilized 94.504 BTC from one wallet to another.Due to the number of dollars mobilized an attacker could be motivated to corrupt the chain.Since last week, the community of bitcoiners commented increasingly on the fact that an unknown user to conduct a significant transaction in which it is mobilized 94.500 bitcoin, in what amounted to almost USD 1,000 million, according to market prices. The transaction has rekindled a debate about the security of the network and the possibility of a chain of blocks of Bitcoin will be attacked in order to steal funds.One of the main discussions about this transaction is focused on the fact that, with an economic incentive enough, an attacker could decide to attack the network, concentrating a large amount of power mining. USD 1,000 million could generate that incentive.Nick Szabo, the ideologue of the contracts smart and one of the respected voices in the ecosystem noted that, although having confidence in the network seems to make sense, an operation of this type of “tempting of destiny”, as explained through his account on the social network Twitter, this 06 of September, a day after the transaction.In this case, it seems possible that some miners collude to perform an attack of retention of a block or an attack of 51% to rearrange the chain, that is to say, alter the chronological order of the blocks to enter a string that is malicious, to be able to appropriate the funds.Image by analogicus / pixabay.com”If the attacker exchanged the BTC to be reversed later for something that is not BTC of the same value, and incurred no external costs (…) still has some profit,” he said. In this case, the security of the transaction depends on the social consensus of the users and not the protocol.
Such confidence in Bitcoin is splendid, but a transaction of 94.500 BTC tempts the destination. If the recipient can do that by rolling back the transaction, you can afford to run an attack of 51% for more than 40 days. Large and very visible, but the security here depends more on trust and less of the protocol itself.Nick Szabo
The main argument of Szabo is that, in any case, the definition of security means that everything in the world depends on “the costs and benefits to the attacker”, versus the breach of a certain security level. In the scenario of the transfer of USD 1,000 million in bitcoin, an attacker could have economic reasons enough to try to re-arrange the chain or roll back the transaction to keep the funds.So, despite the fact that Bitcoin has a high hash rate and the reorganization of the chain would involve a significant amount of investment in order to concentrate enough power to violate your security, at least theoretically, the event can happen.For a transaction like this, of 94.500 BTC, the minimum time to obtain a confirmation that ensures that any attacker would have sufficient incentive, it would take between 40 and 50 days, “depending on the amount of difficulty that change during that time,” said Szabo. The transaction would be exposed.In this sense, the member of the fund investment Multicoin Capital, Kyle Samani, he questioned the possibility that, given these times of confirmation of confidence and minimized the possibility that with the passage of years, an attack of this nature is made more attractive, what is the probability that the blockchain of Bitcoin is deep and viciously reorganized (with more than 100 blocks of change) in a way that put in doubt the security system of the network in the next 10 years? A transaction of Bitcoin equivalent to USD 1,000 million could encourage the attackers.
It would cost 585,000 BTC to reorg the whole chain in 325 days, and an additional 585,000 BTC to catch up with the honest chain from genesis in that time.Either PoW is not the only thing securing Bitcoin or Satoshi should be worried about his coins security after next halving. pic.twitter.com/qbPaPdH7py— Fernando Nieto (@fnietom) April 18, 2019
“It would cost 585,000 BTC to reorganize the whole chain in 325 days, and 585,000 BTC extra to catch up with the chain honest from the block genesis at that time. The Proof-of-Work (PoW) is not the only thing that ensures Bitcoin or Satoshi should worry about the security of their coins after the next halving,” reads the tweet.Others, such as the developer Fernando Nieto, put price scenario theoretical a reorganisation that deep. As published, it would cost 585.000 BTC to reorganize the whole chain of blocks, and it would take about 325 days, in addition to the expense of 585.000 BTC extra to “catch up” with the string honest from the block genesis to the present time.However, it is important to note that these are hypothetical scenarios, because of the investment required, despite the exposure of between 40 and 50 days referred to by Szabo, appears to be prohibitive. According to the analyst, Nic Carter, this debate is nothing more than an “endless time” spent in worry scenarios of reorganization unlikely, instead of “contemplate the fragility inherent in the protocols with a leader, a foundation or a CEO”, as the majority of the projects cryptographic that exist today.It is important to consider that the observations of Szabo on the security of a transaction of this size does not translate into an attack vector per se. In accordance with their own comments through Twitter, the social consensus, among the users and operators of nodes, it could still revert to a scenario of theft.