Currently, Sui's circulation accounts for only 27% of its total supply, while the project party holds at least more than 70% of the node pledge rights, which reveals a certain degree of centralization tendency.

In a blockchain network, nodes usually regard the longest chain as the valid chain and continue to work and expand on this basis. If two nodes broadcast different versions of a new block almost at the same time, the node will first work based on the first block received, and will also keep the other chain in case it becomes a longer chain. When a new proof of work is discovered and one of the chains is confirmed as a longer chain, the nodes working on the other branch will move to this longer chain.

Double-flower attack case:

In 2018, Bitcoin Gold (BTG) suffered a double-flower attack. At that time, BTG was the 27th largest cryptocurrency in the world by market value, with a circulating market value of approximately RMB 5 billion. Starting from May 16, 2018, the attacker carried out a double-flower attack on the BTG network, illegally making more than 388,000 BTG.

The attacker controlled more than 51% of the verification nodes on the BTG network. During the period of controlling these nodes, they sent a certain amount of BTG to their wallets on the exchange, which we call Branch A. At the same time, they sent these BTG to another wallet controlled by themselves, called Branch B. When the transaction on Branch A was confirmed, the attacker immediately sold BTG in exchange for cash. Then, the attacker verified on Branch B. Since more than 51% of the nodes were controlled, Branch B quickly exceeded the length of Branch A and became the main chain, and the transaction on Branch A was revoked. In this way, the BTG that the attacker had previously sold returned to their hands, and the loss of these BTG was borne by the exchange. By controlling more than 50% of the nodes, the attacker achieved a "double-spending" attack on the same cryptocurrency.