The recent consensus issue after the Berlin fork has highlighted the need to spend more resources on ensuring there's no way to break consensus between different clients. I suggest a decentralized bounty that incentivizes security researchers to find such corner cases and report them on a testnet rather than mainnet. The high level idea Make a minimal modification to all clients, to let users get a proof of a state change and the transactions that led to it. Deploy a bounty contract to mainnet, which pays the bounty to the first researcher who proves breaking the state on a testnet. The required change Each client (e.g. geth, OpenEthereum) should implement a new RPC call, eth_stateCommitment(blocknum) which works for recent blocks and returns a state-change commitment signed by the node's private key: { 'blockNum':num, 'preStateRoot':hash, 'postStateRoot':hash, 'transactions':[..], 'signature':{r,s,v} }