Eclipse Attack

An eclipse attack targets particular nodes in a network by surrounding them and obscuring their view of the entire network. For example, if a Bitcoin node has eight connections to other nodes, and an attacker controls all eight of those nodes, the attacker can refuse to relay any new blocks that miners produce. Although the rest of the network continues to process new blocks, the victim node will be unaware that blocks are coming in.

An eclipse attack can be used to take advantage of a victim in a variety of ways. However, the Bitcoin network is built to reduce any node’s vulnerability to such an attack. Bitcoin nodes have the ability to connect to any other node in the network and make as many connections as possible. Additionally, Bitcoin nodes can perpetually connect to other trusted nodes in order to further reduce the possibility of an eclipse attack.