Ethereum's 'Censorship Resistance' Under Threat from Centralization Risk
In the Ethereum network, transactions are not always guaranteed to be included in blocks. The concept of 'censorship resistance' is crucial for a decentralized settlement network like Ethereum.
When a user initiates a transaction, it enters the Mempool, but entering this waiting area doesn't mean the transaction is on-chain. Someone still needs to pick transactions, decide their order, assemble them into a complete block, and submit it to the network for confirmation.
The problem arises at this stage, particularly with the introduction of the PoS (Proof of Stake) mechanism and the PBS (Proposer-Builder Separation) system. This architecture split the processing flow between two roles: Builder and Proposer. The Builder collects transactions, orders them, finds arbitrage opportunities, and constructs a block for maximum revenue; the Proposer selects one candidate block and submits it to the network.
This division of labor has practical benefits but also concentrates power in the hands of few professional Builders. Currently, over 90% of Ethereum blocks are produced by just a few mainstream Builders, making them susceptible to external pressure from legal compliance. This centralization risk can lead to transactions being selectively filtered out or 'silently blacklisted'.