Ethereum (ETH) co-founder Vitalik Buterin claims that it is about to get more difficult for bad actors to exploit a vulnerability that allows them to attack the network, hurting it and its users.
According to reports, Edgar Aronov (deceased), is working on a “personal project”, which would allow for “reorg-on-demand.” Reorg is a programmatic reorganization that allows miners to remove blocks from a blockchain.
They “go back in time” to capture Miner Extractable Valu (MEV). This is a measure of the miner’s profit through their ability to arbitrarily include or exclude transactions from the blocks they produce.
However, the Ethereum network is slated for Ethereum 2.0 merge (expected in late 2021 at the earliest) – when the current Ethereum mainnet “merges” with the beacon chain proof-of-stake (PoS) system.
Buterin and Paradigm Research partner Georgios konstantopoulos claim that Ethereum’s beacon chain implements a PoS protocol called ‘Gasper’, and has two roles during block-production.
- The proposer: A validator is charged with proposing a block.
- Attesters: A group of validators that votes on the block they believe to be the head of the canonical chains.
According to the authors, the merging will make reorg validating easier and less difficult because single or small groups (or even a few) of attesters can’t reorg a block by themselves.
According to the authors, to make a reorg directly, the attacker must control approximately 50% of validators.
Each 12 second there is a “slot” which allows you to propose a block. A shuffling algorithm randomly selects a committee pseudorandomly from each validator. This ensures that attackers do not “have a way to concentrate all their validators into one slot”.
As said before, in PoS, it’s the validators who’re doing what miners do in PoW. They are randomly chosen to create blocks, and they are responsible for confirming that blocks they haven’t created are validators.
According to the authors, short reorgs are common due to latency. Although they are not fatal, they can have serious consequences for the network. These include increased vulnerability to 51% attacks and node costs. Transaction context uncertainty increases vulnerability to Decentralized Finance (DeFi), transactions to accidental failure, worse than expected trade results or MEV extraction.
Long reorgs occur very rarely and are almost always caused by client bugs, extreme network failures, or malicious attacks. […] In extreme cases, frequent reorgs could completely destroy a blockchain’s settlement guarantees and stop it from moving forward.
The authors however stated that
“Today, there are 196k validators in the Beacon Chain, which means that every slot has at least one committee of size 6125. Because an attacker can only control a small number of validators, it is impossible to defeat the vast majority of thousands of attesters.
Additionally, long reorgs are not possible because all blocks that are further than two epochs in the past are “finalized”, meaning it is impossible to revert past them, they said.
Buterin and Konstantopoulos both note that “some risk remains” and that further upgrades are required to avoid them.