Is it possible that the 51 Percent Attack on Bitcoin could Happen?


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51 Percent Attack is an attack on blockchain that dominates 51 percent of its overall computation rate (hash rate). Assuming the current Bitcoin blockchain hash rate is 126.13 Exahash per day, then 51 Percent Attack should be able to dominate up to 64.3263 Exahash per day.

In this case, the Bitcoin miners have the potential to carry out the attack, because they are the ones who have the greatest resources. The fact is that currently, the Bitcoin mining hash rate globally is controlled by miners from China which reaches 2/3 or around 66.66 percent. This means Bitcoin miners from China, if they want, they can do a 51 Percent Attack on the Bitcoin blockchain.

If you ask why they don't want to attack, the answer is simple, because it will mess with the Bitcoin ecosystem itself, including the crypto asset ecosystem in general. There will be distrust of Bitcoin, which in turn reduces the value and degree of Bitcoin itself. However, the chances of success at 51 Percent Attack are also uncertain. This means that considering the enormous cost per day, then the likelihood of confusion and uncertainty, hackers have to think a thousand times.


"miners from china" doesn't mean that there is a single computer in a Chinese government department mining. It is a chinese pool, but miners aren't necessarily in china.

However, if somehow those pools coordinate and perform an attack, they would be able only to make 1 double spent. After that transaction all network would identify them as dishonest nodes and would kick them from the network.

They make more money being honest than dishonest.


Basically, I think of the 51% attack as the 9/11 attack. Yes, it would break the whole cryptocurrency market and dump almost all crypto currently existing. But if I would be a miner, holding such amount of hashrate shouldn't be taken as an advantage to have war in crypto/digital economy. I know most Chinese are good in money making and doesn't want a short-term business. Hence, it would simply imply that they'll still continue mining without attacking the crypto community, as they would only earn less if they do so.

Also, Satoshi still has a block that's left unused with a lot of bitcoin on hold, which is a greater risk and a worst possible btc price dump attack.


Mining pools != Miners.

Miners worldwide that use "Chinese mining pools" can simply opt out if they wanted to; it's not like they're forced to used certain mining pools.

But to answer your title, of course it's possible. A better question is, how likely?


These are just mere speculations but this needs a strong coordination because even if one entity holds more than 50 percent of the hashrates, they only have 10 minutes to modify the next block. In addition, people will not really trust bitcoin in the first place if they figured out that only one entity holds most of the hashrate.

Thus, it is impossible for the 51 percent attack on bitcoin to happen.


Isn't it interesting how information flows through our complex world. I see a news article pop up about btc mining centralization in china, then another about how bitcoin's destiny as "for the people" is at stake and then a thread on bitcointalk is started
. In fact I had just read an article and was doing some research, pondering over the topic and was about to make a post myself.

There is a really useful geospatial visualization of bitcoin miner distribution developed by Cambridge university: According to this map, approx 71% of hashing is conducted in china. I have some points of thought on this topic:

Point 1: How much effort is it to compromise future blocks ?
Is there a function such that E = f(node%), where E is the electricity required to successfully alter the Blockchain and node% is the amount of colluding nodes as a subset of the Bitcoin mining network? 51% attacks take alot of electricity, but what if it was a 60% attack? or 70% or 80%? Does the amount of electricity reduce as the subset of colluding nodes becomes more larger?

Point 2: What could be done with such control over the network?
i guess this has been covered quite extensively. Basically you can edit how future blocks look like (e.g. censor transactions). My question is how does the voting for protocol feature changes get impacted by this?

Point 3: What are the causal factors for centralization in china?
I understood that centralization occurred for 2 major reasons.

  • The shelf life of mining hardware was short and so it was more profitable for chip manufacturers to mine themselves than sell the rigs. This cause colocated centralization around manufacturers in china. This has now changed since we reached 16nm architecture. Andreas Antonopolous describes it in a talk:
  • The electricity price in china is lower. This a main concern for me and it is a way in which government can interfere with the distribution of bitcoin mining network topology.

A ranting note on the second point. The fact that china has cheaper electricity is in itself a manipulation. It places miners in china at an advantage as their cost per hash is inherently less. But it also means that more electricity is consumed with less compensation for environmental degradation. And that is my issue and it is not unique to the case of Bitcoin. China has for decades not considered environmental impact in the scaling of their manufacturing and industrious nature. And it interferes with efforts from other global players (which are already quite shallow). For example, having carbon credits in in Europe means manufacturers in Europe have an extra overhead cost. So, to remain competitive, these processes are moved to china where carbon credits don't exist. The ending result is not that less carbon is produced or funds are gathered to drive carbon offsetting processes. Instead it is just that carbon is produced in another location (in china). And as a convenient side effect, more economic activity is shifted to china.

This is not the fault of the Chinese people, or the miners in our local case. But it is the intentional strategic growth maneuver of the Chinese government which uses a lack of consideration for factors like the environmental impact.

Rant over. But the issue remains




People keep asking about this and if you google the question you get many good answers. And this was from a long time ago, with mining difficulty not as high as it is now. Now it is higher than it was before and long term it keeps getting higher and higher,,, I wonder why people still keep thinking it is possible or viable?


It doesn't happen because it would cost more to pull the attack than any possible benefits. Yes, too expensive to be of use. Remember when the Binance CEO wanted to do it? Took Jihan Wu, of all people, to deter him from doing this.

And, if you are concerned, why are you mining in Chinese pools? Thankfully Bitmain is now breaking apart, but it shouldn't own two pools in the first place.

An Exchange with a pool? What could possibly go wrong? Hey, next time they "lose" money, they have "free" liquidity... Fractional reserve anyone?


Roll Eyes

You just open threads and say whatever comes to mind without even thinking much about it.
How can China do a 51% attack? A country is not a pool.
This is like asking someone do they know so and so because they from China too. How would you know so and so if there so many people in China? How will you even know who is mining and who is not? They not all one entity. This is why what you are saying is like me asking someone from who comes from Australia if they know "bill" It is a massive country so obviously he doesn't know "bill" but the utter cluelessness that makes someone think that they might know "bill" is exactly what you saying.

You know how many people live in China right?


Chinese has big mining pools, geographically but mining pools does not mean that China has biggest miners.

If the mining community see risks, they will re-config and switch their rigs to other pools (are not located in China) and reduce, prevent the risks of 51% attacks.

There is a site that presents cost of 51% attacks on some cryptocurrency networks. I don't know how correct their statistics are but you can take it as a reference. At least I see some delayed statistics (can call as incorrect) with Total hashrate (145,509 PH/s) but it seems to be not a serious problem.

You need to have an overview (not restricted on mining) on Bitcoin network, to exclude myth of Chinese serious effects on Bitcoin network.

There are not many dominant statistics from China with Bitcoin node distribution map: China (today) is ranked at the 9th position.