BNB Smart Chain (BSC) activated the Pasteur hard fork on Tuesday, introducing changes aimed at closing verification and validator authorization gaps while increasing block capacity.
The upgrade, now live on the BSC mainnet, combines three BNB Evolution Proposals: BEP-682, BEP-695, and BEP-675. BEP-682 prevents duplicate validator entries during cross-chain light-block verification, while BEP-695 tightens controls on validator key rotation, slashing, and governance voting. BEP-675 modifies how specialist builders submit blocks to validators.
Pasteur enhances bridge, staking, and governance security by eliminating redundant validator counts in bridge approvals, revoking authority from old validator keys, and blocking restricted addresses from voting. The upgrade also introduces a new block-building route designed to fit more transactions into each block without altering BSC’s 450-millisecond block time.
Under the previous block-building process, builders executed transactions before submitting a proposed block, which validators then executed again before signing. This duplication reduced efficiency within the tight block window. BEP-675 allows builders to submit pre-executed blocks, enabling validators to verify consensus rules, sign, and broadcast before completing full execution checks. Builders may still use the prior route if preferred.
In internal tests on QANet, an environment mirroring BSC’s distributed validator setup, the new route increased throughput by 88%, from 1,237 to 2,324 transactions per second. Average gas used per block rose from 46.35 million to 84.15 million, while block intervals and the 100-million gas limit remained unchanged. BNB Chain noted these figures were derived from controlled test workloads and do not reflect mainnet performance.
The Pasteur upgrade follows earlier optimizations, including the Maxwell hard fork in June 2025, which reduced BSC’s average block time from 1.5 seconds to 0.8 seconds, and the subsequent Fermi upgrade, which further decreased it to 450 milliseconds.
