Securing Blockchain Networks like Ethereum and Hyperledger Fabric

The Sybil attack

One of the classic attacks against peer-to-peer network architectures is the Sybil attack. The attack tries to impersonate the majority of the network nodes, even assuming multiple fake identities, in order to compromise the reliability of the whole network, along with the reliability and integrity of the transactions registered within the ledger.

In this way, whoever succeeds in controlling the majority of the nodes of the P2P network is, therefore, able to invalidate it by setting up illicit transactions (that is to say, contrary to the rules dictated by the network) at will. In one sense, the Sybil attack represents the negation of the blockchain philosophy, as it undermines the trust relationships that can be established ...