Source: Adobe / H_Ko
Ethereum (ETH) co-founder Vitalik Buterin claims that it is becoming increasingly difficult for bad actors to exploit a vulnerability that allows them to attack the network and harm it and its users.
As reported, there has been a lot of discussion lately about a “personal project” (now suspended) by the developer and CEO of the Eventornado hackathon platform, Edgar Aronov, as it would enable “reorg on demand”. A reorg is a programmatic reorganization of chains that enables miners to remove previously confirmed blocks from a blockchain.
They “go back in time” to capture Miner’s Extractable Value (MEV) – a measure of the profit a miner can make from their ability to arbitrarily include, exclude, or rearrange transactions within the blocks they produce.
However, the Ethereum network is planned for the merger of Ethereum 2.0 (expected at the end of 2021 at the earliest) – when the current Ethereum mainnet “merges” with the Beacon-Chain-Proof-of-Stake-System (PoS).
According to Buterin and Paradigm Research partner Georgios Konstantopoulos, Ethereum’s beacon chain, in contrast to Proof-of-Work (PoW) networks, implements a PoS protocol “Gasper” and two roles during block production:
- Proposer: a validator is tasked with proposing a block;
- Attestors: a group of validators who vote on which block they consider to be the head of the canonical chain.
Therefore, the authors argue that reorganization validation after the merge “becomes much less problematic” and is more difficult to perform “because individual attestors or small groups of attestors cannot reorganize a block on their own”.
According to the authors, direct reorganization requires the attacker to control almost 50% of all validators.
Every 12 seconds there is a “slot” that provides an opportunity to propose a block, and a mixing algorithm pseudo-randomly selects a committee of validators for each of them – attackers have “no way of concentrating their validators on a single slot. “
As mentioned earlier, in PoS it is the validators who do what miners do in PoW. Validators are chosen at random to create blocks and are responsible for reviewing and validating blocks that they do not create.
According to the authors, there are always short reorgs due to latency. They are not fatal, but they have “important adverse consequences” for the network, namely: node costs, degradation of the user experience, increased vulnerability to 51% attacks, and uncertainty in the transactional context that increases the vulnerability of decentralized financial transactions (DeFi) to accidental transactions Failure, worse than expected trading results, or harmful MEV extraction.
Long reorgs are rare and “almost always due to extreme network failures, client bugs, or malicious attacks. […] In the worst case, frequent reorgs can completely destroy the execution commitments of a blockchain and prevent their progress. “
However, the authors said that
“Today the Beacon Chain has ~ 196k validators, which means that each slot has a committee with a size of ~ 6125. Therefore, even single-block reorgs are extremely difficult, since an attacker who controls only a few validators has no way of breaking it to beat the honest majority of thousands of attestors. “
In addition, long reorgs are not possible because all blocks that are more than two epochs in the past are “closed”, ie it is impossible to go back over them.
However, Buterin and Konstantopoulos note that “a small risk remains” and further upgrades would be needed to avoid it.
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