
August 19, 2020
Security is paramount for Ethereum Classic. In response to the recent attacks against the network, we are developing a strategic and robust plan to carry ETC forward. As stewards of a public blockchain, we are determined to protect the integrity of the ecosystem. We are investing more resources, human and financial, to enhance security, strengthen the network, and ensure a bright future for ETC.
The network security plan consists of (1) immediate actions we are taking to prevent attacks; and (2) several long-term changes, currently in development, that could be implemented within 3–6 months.
We are taking a number of steps that immediately guard against attacks. This provides new layers of security to the network. These include: Defensive Mining through cooperation with miners and mining pools to maintain a more consistent hash rate and to increase hash rate when needed.
There are different types of proposals currently in development for long-term fixes, all of which require community consensus in order to move forward:
Ethereum Classic’s community is considering several options for increasing resistance to 51% attacks, which could be implemented in approximately 3 months. While these alone will not prevent attacks, they would be part of a series of upgrades on ETC.
One option is PIRLGUARD, developed, and proposed by the Pirl community (Source: PIRLGUARD — Innovative solution against 51% attacks). ECIP-1092 states that instead of automatically synchronizing with any offline pre-mined chain branch, the new protocol should require peer proposing the longer and heavier chain to mine a number of penalty blocks. The number of penalty blocks depends on the number of the original blocks that would be reverted if the chain reorganized and synchronized to the proposed reorganization. Thus, the cost of the 51% attack will significantly increase as the attacker will not be able to publish their private branch without doubling their work by adding penalty blocks. This will protect the network from reverting all the transactions from the publicly mined branch.
Another proposal is enhancing the chain with checkpointing and timestamping (Source: Securing Proof-of-Work Ledgers via Checkpointing). This proposal would employ an external set of parties that securely run an assisting service that guarantees the ledger’s properties and can be relied upon at times when the invested hashing power is low. However, as of yet there is no specific proposal for the Ethereum Classic network. Any proposal would have to be carefully evaluated for its feasibility with ETC.
The main motivation for changing the algorithm is to step out of the shade of the Ethereum network which is powered by the Dagger Hashimoto proof-of-work, also known as Ethash. This could be implemented within 6 months, depending upon the results of testing. As a minority chain with regards to the total hash rate using the same mining algorithm as the Ethereum network, Ethereum Classic is not only vulnerable to 51% attacks, but these attacks are possible to execute due to the available hash rate that can be rented on various platforms.
Switching to a unique mining algorithm could position Ethereum Classic as a leader in its own class of proof-of-work.
The Ethereum Classic community has discussed several algorithms thus far, two of which are promising:
If the community decides in favor of a mining algorithm change, we can start working towards one of the following two options: change to a GPU- and ASIC-friendly mining algorithm such as Keccak256; or an ASIC-resistant, CPU-friendly algorithm just as the RandomX developed by the Monero community.
Switching to RandomX, which is currently used by Monero, might not entirely resolve the issues we currently face. There’s potential to step out of the shadow of the Ethereum network and into the shadow of the Monero network as yet another minority chain.
Using Keccak256 from the SHA3 family would put Ethereum Classic in a unique position as potential leader with regards to hash rate of its own mining algorithm. This would enable ETC to become more independent from its Ethash-based sister chain, significantly reducing the risk of attacks as a result of a shared mining algorithm.
A potential timeline for the proposals is:
The following proposals describe processes helpful in finding consensus for something as involved as a mining algorithm change.
The following proposals deal with the potential to address 51% attacks and increase Ethereum Classic’s resilience against future threats.
The following proposals from IOG are under discussion in the community, with ECIPs due to be published imminently.
The following proposals are relevant for the current discussion but have been rejected by the community in the past.
[Image is Love Padlocks by Nathan Meijer]