What is a 51% attack? What is dual spending?

[Crypto123 0]

The 51% attack:
It is an attack on a blockchain designated by a group or organization of miners to try to control more than 50% of the hash rate or the computing power of the network.

Dual spending:
A type of attack on the bitcoin network. so that it can be defined as the spend of Bitcoin several times
 This would be by sending a certain value to two wallets at the same time, the first is the victim's wallet and the second is the hacker wallet, and this attack needs a large hash force from mining

What is the risk of attack 51%:
If this attack occurs, attackers will prevent new transactions from obtaining assurances, they can stop payments or transactions between most users.
They will also can reverse completed transactions and this means that they can do double spend.
By controlling most of the computing power on the network, they can interfere with the process of registering new blocks. Then prevent the other miners from completing the blocks, which in theory They take over mining new bitcoin blocks and earn all the rewards.

Edited December 21, 2019 by Crypto123
correction

[Crypto123 0]

9 hours ago, amiraliko said:

I think the most important thing about a 51% attack is not what the entity will do with a new block chain. it is only the fact that it could happen and the bitcoin network will crumble.
 

True, this can happen even if its difficulty rate is very large, but if it happens it will cause severe damage to the Bitcoin network and may cause its collapse. This is very dangerous.

[Crypto123 0]

16 minutes ago, BitCryptoCoin said:

Thanms for this. I know much about 51% attack, that blockchain can become centralized by hackers to manupulate to steal crypto.

Your understanding of the attack is good, yes indeed this is what can happen if the attack succeeds because the attackers will have the ability to control the transactions and thus indeed the Bitcoin network can become centralized controlled by these attackers.

[alexisfuentes 2130]

On 12/21/2019 at 6:05 AM, Crypto123 said:

What is the risk of attack 51%:
If this attack occurs, attackers will prevent new transactions from obtaining assurances, they can stop payments or transactions between most users.
They will also can reverse completed transactions and this means that they can do double spend.
By controlling most of the computing power on the network, they can interfere with the process of registering new blocks. Then prevent the other miners from completing the blocks, which in theory They take over mining new bitcoin blocks and earn all the rewards.

I don't remember if it was at then end year 2017 or 2018, but the Ethereum network was intentionally saturated and the mining process was congested, operations at ETH generally do no exceed $0.1 but  congestion was so that the price of gas increased as much as only transactions with values greater than $ 0.5 are processed, even more.

 

Sometimes, with waiting a few minutes or hours, prices decrease. sometimes these strange speaks occur, you can see then here now (image), which does not mean they are such attacks. 

 

source: https://etherscan.io/gastracker

 

The important thing about that image is to see how the price of gas can vary, but that does not mean that times will be better.

 

 

Edited December 22, 2019 by alexisfuentes
Source.

[Crypto123 0]

11 minutes ago, alexisfuentes said:

Sometimes, with waiting a few minutes or hours, prices decrease. sometimes these strange speaks occur, you can see then here now (image), which does not mean they are such attacks. 

 

Yes, there has already been a 51% attack on Krypton ,Shift Token witch relies on Ethereum in August 2016 and a 15% attack had happened on BTG in 2018 and the attackers were able to steal 18 million$.

[PiroSense 2681]

Duplicate post to mine: https://cryptotalk.org/topic/19518-what-is-the-51-attack-and-could-china-possibly-do-it/

 

Use search first before creating another topic, as it might have already been posted in the forum.

Edited December 21, 2019 by PiroSense

[Crypto123 0]

2 hours ago, PiroSense said:

Duplicate post to mine: https://cryptotalk.org/topic/19518-what-is-the-51-attack-and-could-china-possibly-do-it/

 

Use search first before creating another topic, as it might have already been posted in the forum.

Thank you for alerting me, I really did not know that this topic existed for you, but also I think - my topic differs somewhat. You did not explain the double spend and their some different in explain the 51% attack in detail either. Your question was about China's ability to launch this attack. So I think the two topics are a little different. I see that we leave the judgment to the moderators and if they consider it Duplicate post they can delete it.

[vynz 540]

A 51% attack refers to an attack on a blockchain usually bitcoin's by a group of miners, they control more than 50% of the network's mining hashrate, or the computing power of a computer, the attackers prevent transactions from gaining conformation that allows them to halt payments to the users. Dual spending or double-spending is a potential flaw in a digital cash scheme in which the same digital token can be spent more than once.

[PiroSense 2681]

1 hour ago, Crypto123 said:

Your question was about China's ability to launch this attack

I am aware of that. I don't also know if these threads should be merged since they really talk about a single core topic (51% attack). Also, I have made that thread long ago when people aren't really paying attention to such.

[Crypto123 0]

23 minutes ago, Angel Medina said:

It is a subject that arouses my curiosity and interest, and I would like to say that, although it is an attack that is possible according to the majority of computer experts, it has never been done, although it is possible no hacker group has luckily been able to carry this misdeed for its high degree of complexity and its not so scandalous level of benefits. We can see the advantage that they can obtain is not so high because the Game Theory (Nash equilibrium) is revealed. These debates are not only a thing of the present, in the past there were also times of many doubts related to the fantas ’ghost’ ’of the 51 percent attack. Since the beginning of 2014, the cloud mining company `` Ghash.IO '' was dangerously close to 50 percent of the total percentage of hash (or power) of Bitcoin network mining generating insecurities in all those users who have just Discover Bitcoin

It is true that 51% of the Bitcoin network has not been attacked yet, but in theory it is possible, although in practice it is very difficult, especially at the present time due to the huge rise in hash power and the large number of mining devices. Practically no individuals or groups can do that he needs companies with huge potential or even countries.

[Afrizal rahman 2636]

Yes if this attack occurs then they can as they like to control the transaction. from their attacks could in fact make bitcoin destroyed. but I think bitcoin's defense is stronger.

[Satya31 865]

20 hours ago, Crypto123 said:

The 51% attack:
It is an attack on a blockchain designated by a group or organization of miners to try to control more than 50% of the hash rate or the computing power of the network.

Dual spending:
A type of attack on the bitcoin network. so that it can be defined as the spend of Bitcoin several times
 This would be by sending a certain value to two wallets at the same time, the first is the victim's wallet and the second is the hacker wallet, and this attack needs a large hash force from mining

What is the risk of attack 51%:
If this attack occurs, attackers will prevent new transactions from obtaining assurances, they can stop payments or transactions between most users.
They will also can reverse completed transactions and this means that they can do double spend.
By controlling most of the computing power on the network, they can interfere with the process of registering new blocks. Then prevent the other miners from completing the blocks, which in theory They take over mining new bitcoin blocks and earn all the rewards.

Hey buddy thank you for the information. I was not aware of that things. But now i can know something but the thing is not so much clear. As i understand if the double attack occurs then the bitcoin we received can be lost. So it even make out wallet empty. But the both requires a very high amount of hashrate. 

[BTC Future 3946]

51% attack means a miner take control of 51% of the hash power and this way he can actually control the network by diverting the chain and rolling-back transactions. Most alt-coins are vunerable to 51% attacks because their network hash-power is really low. Even BitcoinCash has been 51% attacked. Only Bitcoin, Ethereum and probably Litecoin are safe as the cost for the attacker to rent that much power will be huge and not provide benefits to do so.

[bliznec 22267]

From such attacks here, no one is safe. Many are mistaken, especially those who are just entering the crypto market. But, you need to caution yourself and your investment. 

[Crypto123 0]

On 12/22/2019 at 6:46 AM, PiroSense said:

I am aware of that. I don't also know if these threads should be merged since they really talk about a single core topic (51% attack). Also, I have made that thread long ago when people aren't really paying attention to such.

I am really sorry, I was not really aware of your topic, I do not know if the two topics can be merged, this needs an administrative authority by the administrator, and I am not able to delete the topic because there are posts by members and this may lead to the deletion of these Posts. I do not have a solution to this problem, do you have a solution that satisfies you of this problem?

[PiroSense 2681]

1 minute ago, Crypto123 said:

I do not have a solution to this problem, do you have a solution that satisfies you of this problem?

I don't think of any, and I couldn't advice either since I am not a moderator myself.

 

I understand that you cannot delete such topic since people had already replied. Admins still hasn't seen this issue yet, and this thread might just live here for awhile.

[Crypto123 0]

6 minutes ago, PiroSense said:

I don't think of any, and I couldn't advice either since I am not a moderator myself.

 

I understand that you cannot delete such topic since people had already replied. Admins still hasn't seen this issue yet, and this thread might just live here for awhile.

Thank you for understanding my position, this is exactly what I meant, the best solution is to leave the topic for moderators to see and if they decide to delete the topic I have no problem. This will be our best solution. Thank you again and sorry that I accidentally caused this. It might have been better to do a research before writing the topic as you said.

[Crypto123 0]

On 1/5/2020 at 3:37 PM, TeknoLightz said:

51% can happen to the coins that one organization or person bought 51% or more of their supply and now can attack and own their network, double spending is for when you put a very small fee for a transaction which can take a long time to confirm so you set another transaction with the same numbers but this time you put more fees and now your transaction can go through.

Sorry my friend, but what you are talking about is not double spending !!! Rather, it is called the transaction Stuck in the network, and it occurs as a result of lower fees and the problem is solved when fees increase. While double spending is another thing, which is that a person spends the same transaction twice or sends the same amount to two different people at the same time. To solve this problem the process requires obtaining 6 confirmations to be acceptable.

[Crypto123 0]

2 hours ago, Abuyaman said:

if it happens it will make happen ruthless injure to the Bitcoin meet people and may begin its collapse.
 

Yes, the infection will be very severe for bitcoin and bitcoin fans, but I think this is difficult to happen and the bitcoin network is evolving and has become more secure and secure than before. I think that this has become very difficult, although it is possible to obtain.

[Crypto123 0]

1 hour ago, Mehran Ali said:

Hackers are the one responsible for 51% attack so that they can steal Crypto. But the block chain is becoming more hard to be hacked

Yes, an attack of 51% is really difficult, but it is not impossible. In the recent past, one of the mining companies alone owned about 50% of the mining force in the world and was able to carry out the attack. As mining becomes more difficult, the number of miners will decrease, and only a few miners will remain, and the mining force will be concentrated in their hands. In this case, an attack of 51% may be easier. We hope that this does not happen.

[bentayebsalah 2280]

An attack of 51% is among the weaknesses of cryptocurrencies, but it is not easy to carry out such an attack and to control and convert transactions

[Crypto123 0]

On 1/28/2020 at 4:54 PM, Airin islam said:

Crypto-In total, the current value of all bitcoin is about 1.6% of the value of all gold. It's only about 0.4% of the estimated value of narrow money from The Money Project's report. Bitcoin is, of course, the most well-known and highly-valued cryptocurrency in the the global economy, but it is far from the only one.

You posted the same comment twice and this is against the rules of the forum, it may have happened by mistake, but please note that this could be considered spam by moderators and you get a warning point. Please pay attention to that.

[Crypto123 0]

11 hours ago, frdoch said:

I think it implies Blockchain assaults are normally a gathering of business coins, they control over half of a system's mining hash rate, or a PC's registering power, while assailants intrude on exchanges that permit them to quit paying clients. Double spend or twofold spend is a potential downside of an advanced money venture where the equivalent computerized token can be spent on various occasions.

Yes, dual spending is one of the major disadvantages of the Bitcoin network. To avoid this problem, the transaction must obtain a approval bug of 51% of the hash power on the network. And in the event that a person or company can obtain this great power, he can make double spending easily.

[Mcd0d0 5882]

that was a great and informative posts regarding on what is 51% was.. i hope that those newbies and all members here get an idea on your topic so they will have learn on it..

[Crypto123 0]

2 hours ago, thangvn00lc said:

The 51% attack, also known as the 51% attack, refers to an attack on blockchain, in which such an attack is still a hypothesis - because a group of operators controls more than 50% of the function. amount of network mining, or computing power. Attackers will be able to prevent new transactions from achieving confirmation, allowing them to pause payments between some or all users. They can also reverse completed transactions while they take control of the network, meaning they can spend double the amount they have.

They almost certainly won't be able to create a new currency h

Very good, yes that is, it is an attack on the Bitcoin blockchain network, i.e. transfers of bitcoins need to sign 50% of the miners who are on the blockchain and in the event that someone is able to get more than this number or 51% then they can sign any transaction and spend more From time and this is called double spending.