a16z Crypto Analyzes the Fundamental Trade-off Between Censorship Resistance and Low Latency in Blockchains

ME News reports that on May 21 (UTC+8), a16z Crypto published an article exploring the fundamental tension between blockchain “censorship resistance” and “low latency,” noting that any Byzantine Fault Tolerant (BFT) blockchain protocol with censorship resistance requires at least five communication rounds for its optimal good-case latency when up to one-fifth of validators may be malicious, whereas traditional BFT consensus requires only three rounds at minimum. The article explains that in traditional BFT protocols, block proposers hold both the power to construct blocks and to advance consensus, enabling them to censor specific transactions—a root cause of many MEV issues. To address this, Ethereum is researching FOCIL/EIP-7805, while Solana is exploring mechanisms such as Constellation and MCP, all of which center on having validators pre-collect “inclusion lists” of transactions that cannot be ignored before a block is formally proposed. a16z Crypto states that achieving censorship resistance requires two additional communication rounds: first, users must broadcast their transactions to all validators; then, validators must confirm and record these transactions into inclusion lists before consensus can begin. Thus, in a partially synchronous network environment, no protocol design can simultaneously achieve BFT and censorship resistance in only four rounds—five rounds represent the mathematical lower bound. The article emphasizes that while censorship-resistant mechanisms increase protocol latency, they significantly reduce the actual “effective latency” experienced by users. In systems lacking censorship resistance, transactions may be indefinitely delayed due to validator censorship; in systems with censorship guarantees, transactions are guaranteed inclusion in a block within at most five communication rounds, making transaction confirmation times far more predictable. (Source: ODAILY)