$SUI may have a double-spending attack

The current circulation of sui is only 27%, and the project party controls at least 70% of the node pledges, which is undoubtedly centralized.

As we all know, blockchain nodes always regard the longest chain (51% theory) as the correct chain, and continue to work and extend it. If two nodes broadcast different versions of new blocks at the same time, they will work on the basis of the first received block, but will also retain another chain to prevent the latter from becoming the longest chain. When the next proof of work is discovered and one of the chains is confirmed to be the longer one, the nodes working on the other branch chain will switch camps.

Double-spending attack case

In 2018, a double-spending attack on Bitcoin Gold (BTG) occurred. BTG was the 27th largest cryptocurrency in the world at the time, with a circulating market value of 5 billion yuan. Since May 16, 2018, attackers have successfully carried out a double-spending attack on the BTG network, seeking a huge profit of more than 388,000 BTG.

The attacker controls more than 51% of the verification nodes on the BTG network. During the period of controlling the nodes, he sent a certain amount of BTG to his wallet on the exchange. We named this branch Branch A. At the same time, he sent these BTG to another wallet under his control. We named this branch Branch B. After the transaction on Branch A was confirmed, the attacker immediately sold the BTG and got the cash. Subsequently, the attacker verified on Branch B. Since he controlled more than 51% of the nodes, the length of Branch B soon exceeded the length of Branch A. Branch B would become the main chain, and the transaction on Branch A would be rolled back to the previous state. The BTG that the attacker had previously exchanged for cash returned to his hands, and these BTG were the losses of the exchange. In this way, the attacker achieved "double spending" of the same cryptocurrency with more than 50% control.