51% attacks become commonplace

Monacoin, bitcoin gold, zencash, penis and now Litecoin cash.

At least five cryptocurrencies have recently been hit by an attack that was more theoretical than real, in the last month. In each case, the attackers were able to amass sufficient computing power to compromise those smaller networks, rearrange their transactions, and run away with millions of dollars in a robbery that may be the crypto equivalent. a bank hold-up. More surprisingly, the so-called 51% attacks are a well-known and dangerous cryptocurrency attack vector.

Although there have been some examples of such attacks that have worked successfully in the past, they were rather rare. Some technologists went so far as to claim that minors on certain blockchains would never be victims of such attacks. The recurring argument that this type of attack is too expensive and they would not get as much money!

But that does not seem to be the case anymore.

NYU computer scientist Joseph Bonneau published last year researching the costs of running blockchain attacks by simply hiring computing power rather than buying all the equipment.

A conclusion he drew? These attacks were likely to increase. And, it turns out he was right.

"In general, the community thought it was a distant threat, I thought it was a lot less distant and I was trying to warn of the risk," adding:

"I did not think it would start so soon. "

In the attacks
Cryptocurrencies aim to solve (among other things) a long-standing computer problem called the "double spending problem".

Essentially, without encouraging computers to monitor and prevent bad behavior, messaging networks were unable to act as cash systems. In short, they could not prevent someone from passing the same piece of data five or even a thousand times.

This is why cryptocurrencies work on algorithms, with miners who consume electricity and make sure someone's money is not stolen.

To make money using this attack vector, hackers need some coins to be operational. An attacker can not do what he wants when he has accumulated the majority of the hash power. But it is able to double the transactions under certain conditions.

It would not make sense to accumulate all that expensive hash power to double a $ 3 transaction. An attacker will make this investment only if he can steal thousands, even millions of dollars.

As such, hackers have found various clever ways to make sure conditions are right for them to earn money. That's why the attackers of monacoin, bitcoin gold, zencash and Litecoin ensured that these corners were all on targeted platforms holding millions in cryptocurrency.

By accumulating more than half of the network's hash power, the bitcoin gold attacker was able to double two very expensive transactions sent to an exchange.

Thanks to three successful zencash attacks (a lesser-known cryptocurrency that is a fork of Zcash), the attacker was able to flee with more than 21,000 zen (the zencash token) worth more than $ 500,000 to the current time.

Although the Verge attack was a bit different since the attacker exploited unsecured rules to confuse the network by giving him money. Although it is clear that the attacks were targeting the lower layer of the protocol, researchers are wondering if they are technically 51% attacks.

Small parts in danger
If these attacks were rare for so long, why do we suddenly see an explosion?

In a conversation, the researchers argued that there was not a single clear reason. On the contrary, there are a number of factors that have probably contributed to the development of these attacks. For example, it is not by chance that small pieces are those that are attacked. As they have attracted fewer miners, it is easier to buy (or rent) the computing power needed to make up a majority share of the network.