As reported by the Ethereum Classic team, MESS is an adaptation of the "Exponential Subjective Scoring" security framework, proposed by Ethereum co-founder Vitalik Buterin in 2014. According to information published by Ethereum Classic this October 1, MESS was approved by developers and community members. The developers believe that MESS will help secure the network. The note clarifies that some of the network-enabled clients, such as Hyperledger Besu and Multi-Geth, do not have the MESS security feature enabled.
"The Besu team is working to add the MESS security feature in the future," they state, adding that Parity Ethereum, OpenEthereum, and Geth-Classic are outdated clients. "If you are currently running one of these clients, you will need to switch to Core-Geth to be protected by MESS and for continued development and support."
According to ETC Labs, MESS prevents 51% attacks by "red flagging" attempts to reorganize large blocs. It happens because MESS qualifies as suspicious the large reorganizations used to launch these attacks. Additionally, with the new tool, nodes must make a subjective decision to prefer the chain segments they see first, over the segments they see later.
The developers add that MESS respects the idea that "the code is law", as the principle of the network. It means that the heaviest chain wins. According to ETC Labs, the new protocol respects this rule. If the preferred chain is the first one the node sees, "building a long and potentially malicious chain in secret will not be feasible."
MESS arises as part of the search for solutions to face the security problems of the Ethereum Classic network, after having suffered three attacks of 51% during the month of August. Such a fact made it "relatively cheap to dominate the chain's recent history." In response to the 51% attacks, ETC Labs had implemented "defensive mining."
