Ethereum 2.0 the solution to "reorg as a service" according to Vitalik Buterin

By: Bharggavi Ssayee

August 6, 2021 6:00 AM

A few weeks ago, a developer on Ethereum (ETH) created a heated controversy after revealing the fact that he was working on a tool allowing miners to reorganize the blockchain for their benefit. Although the latter has stopped his research due to too much pressure, Vitalik Buterin and Georgios Konstantopoulos have just published a paper explaining how Ethereum 2.0 would make such a maneuver impossible.

Reorg as a service: the heated debate

On July 9, developer @EdgarArout ignited Twitter with the release of a surprisingly surprising tool he was working on. In practice, this would allow miners to adopt a modified version of the Ethereum client. The latter could thus accept bribes to effect a short reorganization of the chain.

This tool can have several uses. As a first step, users practicing arbitrage could ensure that the trade is profitable. However, this service would also allow malicious users to attack DeFi protocols, a trend already far too prevalent in Ethereum to be encouraged.

In addition, this proposal presents several dangers vis-à-vis the blockchain itself. This could remove the immutability of Ethereum and cause serious slowdowns in validating transactions.

On July 15, the latter finally decided to abandon his project in the face of growing pressure from the community. However, this does not prevent another similar project from being in development, without it having been formalized.

EdgarArout publication - Source: Twitter

“The idea of mev-reorg is on hold for now (private repo) - the pressure to quit and the threats were too much of a burden and it wouldn't be fair for my family to have to deal with it all. "

Publishing EdgarArout on Twitter

The problem of too frequent reorgs

On July 20, a few days after @ EdgarArout's announcement, Ethereum co-founder Vitalik Buterin, along with developer and researcher Georgios Konstantopoulos, published a paper explaining how the move to proof of stake (PoS) would make impossible such behavior.

In practice, channel reorganizations are not harmful to the network, if they appear occasionally. Indeed, these can occur following latency problems, during which 2 minors can validate a block simultaneously. However, the network would be in danger if they were to become commonplace.

“In the worst case scenario, frequent reorgs can completely void a blockchain's settlement guarantees and prevent it from progressing. "

Publication by Vitalik Buterin and Georgios Konstantopoulos

How does PoS solve this problem?

In the case of a proof of work (PoW) blockchain, as is currently the case with Ethereum, the blocks are solidified in series. This means that when a block is mined, a single competing block can take its place and reorganize the chain. Seconds later, when a second block is mined, a chain of 2 competing blocks is needed to reorganize. Thus, as blocks are mined, the difficulty of reorganizing the chain increases until it is impossible to reorganize the first block.

In the case of the PoS which will be used by Ethereum after “The Merge”, the validation of the blocks and their addition to the chain are managed by 2 entities:

The proponent: who proposes the block;

The attesters: a group of validators who vote for the block they consider to be the head of the chain.

These attesters are chosen at random in the form of a committee made up of 1 / 32nd of the validators.

“Today the beacon chain has ~ 196,000 validators, which means each block has a committee size of ~ 6,125. Therefore, even single-block reorganizations are extremely difficult, as an attacker checking only a few validators has no way of beating the honest majority of thousands of attesters. "

Publication by Vitalik Buterin and Georgios Konstantopoulos

Indeed, it is impossible in this case to bribe all the members of the committee.

Pending the merger of Ethereum 1.0 with Ethereum 2.0 and the transition to Proof of Stake at the end of the year, the Ethereum network will deploy the hard fork London on August 4. This hard fork will integrate the EIP-1559 and is likely to stir up debate once again.