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and 51% attacks do not require you to have 51% of all nodes on the network. Just 51% of all Active nodes on the network. If someone finds a zero day exploit an
by cobookman 9y ago
and 51% attacks do not require you to have 51% of all nodes on the network. Just 51% of all Active nodes on the network.
If someone finds a zero day exploit and manages to crash a large number of ethereum nodes they could do a 51% attack with a relatively small number of nodes.
- CryptoPunk 9y agoThat's incorrect. A 51% attack means an adversary having 51% or more of the hashing power (calculated as hashes generated per second) and using it to disrupt the normal operation of the blockchain. A party with 51% of hashing power can single handedly create a blockchain that other nodes will accept over any competing chain, meaning they can rewrite history, or prevent any new transactions from being confirmed. If consensus were based on number of nodes, the network could be easily Sybil attacked, given the cost of running what appears to be a node is next to nothing. It would also be difficult to make such a consensus protocol usable, as there's no efficient way to poll a large number of network nodes.