51% attack now Possible by the Top 3 Mining Pool Operators

[aardvark15]

I don’t think it’s easy to coordinate that kind of attack at this point. You would need to get all three to agree to do something drastic an I just don’t think they will all cooperate to do that.

[pixie85]

I don’t think it’s easy to coordinate that kind of attack at this point. You would need to get all three to agree to do something drastic an I just don’t think they will all cooperate to do that.

It's not and even if 3 major pools could do it they won't because each of them has a lot to lose and not a lot to win.

If one of them decided to play the other 2 it could make them lose money and time trying to perform an attack, fail and compromise themselves. The operator who would expose them would make more money and gain respect of the community for exposing the attack. Also a stable network benefits all miners. If they were able to compromise it by attacking it would be like they bought a car and then burned it in public to get insurance money. It's not worth it!

[omfg.xekcep]

Well, if you complain ongoing things then suggest something. May be your advice will be priceless for the community. Unfortunately I am not an expert that is why I cannot check out the given information. By the way I could not understand if the former situation was better than now. In other words I am not sure whether your complaint takes place therefore I do not want to be unjust on discussing the particular situation. As far as I know hacker's attacks are inevitable anyway but how it works unfortunately I do not know

[franky1]

though the numbers of the pools is not actually 3 people with 51%. but more people/individuality.
a few people still dont get the point that even if its 1-3 people in such a scenario doing the attack
the most that would occur is the pool becomes selective over what transactions to include or exclude.

so again for emphasis what can this attack do and cant do
1. CANT DO: change bitcoin rules
2. CANT DO: steal satoshi's stash or MTGox stash*

2. CAN DO: reverse recent confirmed transactions*
3. CAN DO: prevent new tx from confirming

this is because although going back 1 block rewriting what tx's is included and solving that block and building a new block ontop to catch up and then another block to ovetake and orphan off the top3 blocks of the public chain to replace for the attackers top 3 blocks. the further back the attacker goes the more time is wasted resolving old blocks while the public pools are building ontop the public chain

EG do simple dummy demonstration without the variables
 lets say its 60% hash dominance and lets put it into minutes attacker/public take to make a block
(attacker 8mins, public 12min)

A) block 1000 block999 blok1000 blok1001 blok1002 blok1003 blok1004 blok1005 blok1006 blok1007
P) block 1000 block1 0 0 1 block1 0 0 2 block1 0 0 3 block1 0 0 4 block1 0 0 5 block1 0 0 6 block1 0 0 7

as you can see it can take 7 blocks to go back just 1 block and then catch back up
go back 2 blocks can take 14 blocks to catch up
go back 3 blocks can take 21 blocks to catch up
go back 4 blocks can take 28 blocks to catch up

as for not going back to edit old blocks but instead just 'empty block' new blocks. an attacker is not guaranteed to always have the 8min 'luck' there are still times where other pools will be 'lucky' and beat the attacker pool to being first to broadcast a block

this is why although one tagged 'pool' looks like it has 14.9% and another tagged pool has 13% this does not mean the 14.9% pool is going to win every block and no other pool everwins again.. because the pools would be winning every block if that were the case. but its not. even pools with highest hashrate dont win all the blocks

(note to the anal knickpickers. yes i simplified the demo down. yes theres more variables involved. no need to shout the obvious. but the end result is the same. i dumbed it down to make it a simple explanation not a technical, ego chest thumping, nerd jargon attempt.)

[patroncito]

****WRONG****

[ilovealtcoins]

The difficulty is increasing and individual miners cannot afford the mining and financial power because they no longer profit from Bitcoin mining.  If the world's largest Bitcoin mines allied together to create a 51% advantage, it would be disastrous for Bitcoin.  This is entirely possible in the future.

[DarkDays]

https://www.blockchain.com/en/pools

Top 3 mining Pool Operators now have 56% control, so if they collude they can easily 51% attack bitcoin.

Centralization has occurred. Decentralization is dead for bitcoin.

So now only 3 people secure bitcoin.

I am sure the follow up posts will be claiming , they would never do that.  
But whether they do or don't, You are trusting only 3 guys with keeping the bitcoin network safe from 51% attack.
(Used to be 4 guys) So much for Trust-less.

Discussion to remove pooling as an attack vector is here :
https://bitcointalk.org/index.php?topic=5194239.0

But like most things here , the Bitcoin Religious Fanatics see no problems.  

Let the cover up posts begin.  

Pretty ridiculous statement to be honest. You could always say if X number of mining pools collude then they could launch a 51% attack.

In any case, if they were successful, then the network would simply blacklist the offending miners, and they would get away with a max of 1 double spend.

Not worth the effort. The bitcoin network is beyond the realm of 51% attacks now.

[dohh]

https://www.blockchain.com/en/pools

Top 3 mining Pool Operators now have 56% control, so if they collude they can easily 51% attack bitcoin.

Centralization has occurred. Decentralization is dead for bitcoin.

It is important not to forget, that you need 51% of hash power to succeed with 100%. You can have a very reasonable success rate from levels much lower already.

[poopsmear]

Is a 51% attack legal to do? Or is it illegal?

[dohh]

Pretty ridiculous statement to be honest. You could always say if X number of mining pools collude then they could launch a 51% attack.

In any case, if they were successful, then the network would simply blacklist the offending miners, and they would get away with a max of 1 double spend.

Not worth the effort. The bitcoin network is beyond the realm of 51% attacks now.

You sure, that you have understood the blockchain correctly?
If they succeed, they will "blacklist" all the remaining miners and alter the blockchain. Not vice versa. Duh.

[konfuzius5278]

Is a 51% attack legal to do? Or is it illegal?

For my opinion its legal. Its open source and no one can say this code is right or wrong.
You simple set up a node with your own rules. When you/people mine on it the 51% of hash rate, you make the rules !

When you double spend coins on an exchange its illegal. But the attack itself not.

[squatter]

Is a 51% attack legal to do? Or is it illegal?

This attorney did a legal analysis and found that 51% attacks are illegal under the Computer Fraud and Abuse Act, which could entail both criminal and civil penalties for the attacker.

That's just the word of a lawyer, though. Until legal precedent is actually set in the courts, we can't be sure what would happen.

[dohh]

Is a 51% attack legal to do? Or is it illegal?

This attorney did a legal analysis and found that 51% attacks are illegal under the Computer Fraud and Abuse Act, which could entail both criminal and civil penalties for the attacker.

That's just the word of a lawyer, though. Until legal precedent is actually set in the courts, we can't be sure what would happen.

No one will take this case, I assume. It would requite unreasonably big effort to disclose who is behind this kind of hacks. And even if it was, whole crypto space would lose its "anonymity" and collapse even faster than it will.

[squatter]

This attorney did a legal analysis and found that 51% attacks are illegal under the Computer Fraud and Abuse Act, which could entail both criminal and civil penalties for the attacker.

That's just the word of a lawyer, though. Until legal precedent is actually set in the courts, we can't be sure what would happen.

No one will take this case, I assume. It would requite unreasonably big effort to disclose who is behind this kind of hacks. And even if it was, whole crypto space would lose its "anonymity" and collapse even faster than it will.

Identifying the attacker should be trivially easy. Just look at who published the attack chain. Like the OP suggested, the attack would probably entail collusion among multiple pools since sourcing the hardware to independently attack the network would be nearly impossible.

Identifying and organizing a cohesive class of victims under a single legal jurisdiction sounds extremely challenging, though. The CFAA is an American law as well -- it's unlikely that Chinese pool admins, for example, could be successfully brought to justice under it.

[dohh]

This attorney did a legal analysis and found that 51% attacks are illegal under the Computer Fraud and Abuse Act, which could entail both criminal and civil penalties for the attacker.

That's just the word of a lawyer, though. Until legal precedent is actually set in the courts, we can't be sure what would happen.

No one will take this case, I assume. It would requite unreasonably big effort to disclose who is behind this kind of hacks. And even if it was, whole crypto space would lose its "anonymity" and collapse even faster than it will.

Identifying the attacker should be trivially easy.

That is bullshit. You are missing the essence of "distributed ledger." If the 51% attack succeeds, then the blockchain is altered and that is a new true version of the database.

[blandana]

Probably not illegal.  As much as anyone doesn't want that to happen it could happen.  I'm not sure how everyone would react though.  If bitcoin works trading wise still if it happens I'm sure everyone is just going to move on.

It would probably only be illegal if they started "messing" with transactions.  If it became a problem there are laws that would be broken somewhere probably but I'm not sure if it's illegal if a group "hashes" so much that if it cancels out other "block" discoveries that it's illegal.  Or something like that.

[alyssa85]

Is a 51% attack legal to do? Or is it illegal?

It's legal, and it's usually done to destroy a coin.

In the early days when alts were first being released, many were killed off by 51% attacks by bitcoiners who hated the thought of alts existing and thought that bitcoin should be the only crypto.

That's the reason why the only alt with sha256 is bitcoincash which didn't fork till 2018. The other alts adopted scrypt, which meant the bitcoin miners couldn't easily switch to mining alts and destroying them.

Back to the topic of discussion: it's unlikely that the top miners in bitcoin will attempt a 51% attack, because that would mean destroying their own business.