In the next series of articles, BTCManager will detail the seven questions raised by Ethereum's co-founder V God. These seven questions are the most relevant features of this thriving ecosystem. These issues range from mining (as described in this week's column) to governance. The series was inspired by a discussion between V God and a WeChat group called Mars Finance Global Family.
Translated from www.8btc.com
(This article is the first article in the series)
Worried about 51% of attacks
Of all potential attacks against cryptocurrencies, 51% of attacks should be one of the most feared attacks. This type of attack will allow an attacker to have full control over the cryptocurrency and generate a lot of confusion.
Such an event occurs when a miner attacks an given blockchain to take over the approval process that is currently processing the transaction. A successful attack does not allow full control over the cryptocurrency, but it can significantly change the way cryptocurrencies are used.
For example, such an attack would not allow a malicious miner to arbitrarily create new coins or change historical transactions, but they may be double-flowered or completely stopped under current control.
Bitcoin Gold: Successfully attacked
The most obvious example of a 51% attack is Bitgold. In May 2018, the malicious miners controlled a large amount of hashing power on the Bitcoin Gold network in four days, so that they were able to make double-flower transactions, and eventually they stole Bitcoin Gold worth more than $18 million.
Even when updating the wallet and reversing the entire block to increase the confirmation time, Bitcoin Gold still has serious problems.
As far as Bitcoin Gold is concerned, the attack was caused by a series of events. Since the mining algorithm used by Bitcoin Gold is Equihash, this mining platform is very similar to ZCash, which has ample supply of hashing power - it has about 500 megahertz in May 2018. Second, the value of Bitcoin Gold was high at the time, about $75 per coin. Third, the total hashing power on Bitcoin Gold is very low, only about 40 megahertz.
In order to attack Bitcoin Gold, the malicious miner simply creates a custom mining script and deploys it to a 40 megabit hash power miner. At a cost of 1 bitcoin per megabit per 100 hours, a 40 megahertz computing system requires only about 40 bitcoins in 100 hours.
Can Bitcoin attack Bitcoin?
Larger networks, such as Bitcoin and Ethereum, have quite high hashing power, and it can be said that 51% of attacks cannot affect them. Bitcoin's current computing power is about 40 Petahash per second, while Ethereum is 288 Terahash. Therefore, there are only two ways to attack them in this way.
Either way, either trying to double the hashing power overnight or colluding more than 51% of the miners through collusion and monopoly.
However, V God believes Bitcoin's protocols are vulnerable to bit continental and related pools because they have enough hashing power to compromise Bitcoin at any time. The main point is that most Bitcoin miners operate either on the Bitland platform or on the Bitland or the platform they control.
This means that malicious code can be injected into the pool at any time, or it can be written into the mine through software updates to affect the mining method of the mining machine.
Will Antbleed cause 51% of attacks?
Bitcoin has direct responsibility for the "Antbleed" vulnerability discovered in April 2017. The vulnerability was hardcoded into most mining machines, allowing BitNet or malicious hackers to shut down all miners running the system.
This means that most people's attacks will reduce implementation costs. Bitland’s response at the time was that this was by no means a loophole, but a feature:
We have never intended to use this feature on any ant miner without the owner's authorization. This is similar to the remote deletion or shutdown feature offered by the most famous smartphone manufacturers.
Subsequent repairs to Bitland still introduce potential calls to bit-continent servers containing miner information.
Although the source code of the Bitland Mining Machine is public, the mine software that runs them is confidential and has not received public attention. As of the date of this publication, the following five bitcoin pools control more than 50% of the bitcoin hashing power:
- BTC.com - 19.1%
- ViaBTC - 12.4%
- AntPool - 12.2%
- BTC.TOP - 10.7%
- SlushPool - 10.7%
These mines accounted for 65.1% of the total hash calculation of the Bitcoin network. If the owners of the five mines cooperate to collaborate on any combination of their mines, then this will have a disastrous impact on mining.
Matt Odell talks about 51% of attacks
When talking about these issues, Bitcoin developer Matt Odell said in an interview with BTCManager:
(We) don't know the composition of each pool. How much of their server farm is directly controlled by Bitland, and how many are independent miners using the Bit Continental Pool because it is a stable, reliable, low-density mine.
The only check on the calculation of the mining pool depends on a single miner. Speaking of this, Odell said:
The mining pool operators have a lot of power, but these individual miners can change their own mining pool if they don't like the way the mine is operated. It provides a check on soft power if Matt Corallo's betterhash in the future If adopted, then these mining pool operators will have less computing power.
Betterhash - does it really make things better?
The reason why Betterhash solves this problem is how each miner operates in the mine. The "Stratum" protocol requires the operator of the mining pool (such as Bitland) to create a template for the block, which then requires the miner to build on the template.
This means that the mine operator can review the work of the miners. Since the pool can choose which transactions to include in the block, the pool may also reject some transactions.
During the bitcoin "full blocks" period prior to the isolation of Witness and Lightning Networks, all Bitcoin pools were providing "block accelerator" systems.
The Betterhash proposal submitted by Matt Corallo in March 2018 is currently not implemented because the standard channel will change the way the system works. The proposal transfers the construction of the block template to a single mining machine and allows the miner to choose which transactions the block will contain.
Attack on Stratum
In the nearly 12 months since Bitcoin rose to $20,000, almost every bitcoin block that was dug up was a full 1 megabyte. During this period, the debate between Bitcoin, supporters of quarantine witnesses, and supporters of large blocks about increasing block size reached an almost fanatical level. The battle ended on August 1, 2017 with the hard fork of Bitcoincash.
During this time, both ViaBTC and BTC.com provided "transaction accelerators" that required miners to use these accelerated transactions to dig blocks while leaving the payment for accelerated transactions to themselves.
This opens up another related attack vector. Governments or other malicious organizations can ask the pool to use the same amount of power to stop transactions and keep silent on the transactions they block.
Audit of Bitland
The cryptocurrency expert Bryan Bishop recently proposed an independent third-party audit for Hash Computing in Bitland. He told BTCManager on Twitter:
It is possible to conduct an independent, external audit of the bit-continental hash calculations. I think that if they can stick to the end, it will be a huge victory for greater transparency. A good audit will combine the technical expertise of Bitcoin developers with forensic accounting.
BTCManager contacted Bryan and asked several related questions. When asked about Betterhash's proposal, Bryan said:
I think Matt Corallo's Betterhash proposal will help a lot. At the same time, I am puzzled by Bitcoin's control of many large bitcoin mining pools.
When the Bitcoin community faced these concerns, Bittland only provided some transparency policies on its website, excerpts as follows:
- Bitland will publish data on self-mining every 30 days.
- A zero tolerance policy is applied to the mining of cryptocurrencies.
- They will never dig out empty blocks.
- They will provide the public with information on the transport and quantity of the new mining machine.
Information about their cooperation with other mines, or how they choose to dig out which deals, and even how their mines work, has not been disclosed. BTCmanager asked Bitland on these issues in a forum and email supported by Bitcoin, but did not receive a response. If we can get a reply from the company, then we will update this article.
Isn’t Ethereum not attacked?
It turns out that Ethereum is more resistant to attacks than Bitcoin; however, they face the same Stratum protocol difficulty as the pioneer cryptocurrency. In other words, Ethereum has been implementing a Proof of Interest (PoS).
This will require some major changes to the entire Ethereum network system. "Serenity" is the code name for the system, and he also includes the Casper equity certificate. The next step for Ethereum will be "Constantinople" and will provide module building for this purpose. According to the developers of Ethereum, the implementation of the project has been postponed to a certain period between 2019 and 2020.
This means that the large pools in Ethereum can now collaborate in a malicious way. The top four Ethereum mine pools are:
- Ethpool / Ethermine - 43.88%
- Nanopool - 20.91%
- MiningPoolHub - 10.12%
- Miner2 - 8.6%
BTCManager also tried to contact them via Ethermine and Nanopoo's support system and email, but so far we have not received any response. If we receive a reply to the pool operator, we will update this article.
51% of attacks are real threats. These threats come not only from external forces supported by the state, but also from malicious attackers. Developers of cryptocurrencies are continuing to review proposals and propose multi-year development plans, while attackers are also developing their own plans.
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