We have generally two kinds of security related to state machine control
1: consensus fault detection and punishment
2: manipulated tx & state-change attempt detection and punishment
We have controlling mechanism for the risk of 1.
Also, cross-chain validation(aka shared security) can enhance such security
But, we don’t have any mechanism to protect the blockchain from risk of 2.
i think the ones who search and submit such evidence of 2 are defined as “fisherman” in polkadot.
i agree that stand-alone fisherman is not a sustainable incentive design because there exists high probability that he/she might not find any evidence for a long time, resulting in zero rewards.
but, i think dedicated validators with good reputation will be willing to run such “fisherman” binary to provide additional security for the security of the network and users. so, i expect some good validators will operate this.
also, fisherman does not need very high quality security setup, so it should not be so expensive to additionally operate this node.
this utility is much more necessary in smaller, newer network with less collaterized security(less staked assets), less decentralization.
and also, even though interchain collaterization(shared security) might support security on “consensus fault control”, it is not providing additional security to detect “manipulated” transactions and state changes
So, in result, I think we need an additional function on evidence/slashing module to cover the malicious behavior of 2, and also we need a new tendermint MODE to operate for detecting and reporting such malicious act of validators
I hope to hear opinions on this matter from the community.