ETC Cooperative has published the report “ECIP Comparison for 51% Attack Resistance”. This entity takes control of promoting and supporting the development of Ethereum Classic. It was written by Kostis Karantias of Input Output Hong Kong, the company in charge of the development of Cardano. Contributors include two other IOHK developers and the Director of Developer Relations for ETC Cooperative, Stevan Lohja.

The Ethereum Classic network has been suffered from at least 3 attacks of 51% in August alone. The developers of ETC have received a lot of pressure from the community to find and promote a solution. The report shows that the attacks have reduced trust in the ecosystem and raises the possibility of an exit of ETC from exchange’s lists:

IOHK has a long association with ETC and its community. To mitigate these attacks and secure the ETC network, the IOHK team has conducted an analysis of the different options and proposals found through the ETC community.

Proposals to prevent 51% attacks on Ethereum Classic

The IOHK team works on 6 proposals to mitigate the problem posed and preserve the properties that make Ethereum Classic a “robust” transaction ledger. The first proposal goes by the name “Checkpointing” and is based on establishing a checkpoint mechanism to make each block irreversible and prevent it from being reversed.

This solution involves designating an entity to select a checkpoint for a block that will be considered the canonical chain that other parties must follow. This solution provides three advantages: reduction of exchange confirmation time, maintains the Ethereum Classic consensus protocol and does not alter mining rewards, achieves the “liveness” needed by a transaction ledger, has been proven.

The second proposal is “Timestamping”, this solution proposes to base the network security on another ledger, which in this case is Bitcoin. Hence, Ethereum Classic miners would use a timestamping feature to create blocks linked to the Bitcoin blockchain. However, to implement it, the ETC nodes must be connected to the Bitcoin network.

Another proposal discussed is based on a smart contract platform called Rootstock (RSK). Also based on a connection to the Bitcoin blockchain, RSK is powered by “SmartBitcoins” (RBTC). This proposal suggests implementing checkepoints within Bitcoin blocks and assigning a score to each block. RSK would provide the information on the Bitcoin blocks with a smart contract.

The other proposals analyzed are Veriblock, PirlGuard and MESS. The first two are based on the Bitcoin and Ethereum blockchains’.

Since the moment the Ethereum Classic network began suffering from attacks, the developers have implemented a strategy to improve network security. Among them: “defensive mining” in conjunction with mining pools to increase the network hash rate, network monitoring, coordination with exchanges to agree on “secure confirmation time”.

Meanwhile, the community discusses and decides on the best long-term solution. ETC Cooperative’s report could be an important step in term of that. However, the report has pointed out that the solutions outlined above have their own trade-offs and should be considered as temporary. Getting to the root of the problem will need “innovation, growth, and belief in the ecosystem”.