$BNB Smart Chain (BSC) implemented its Pasteur hard fork on Tuesday, addressing bridge verification and validator authorization issues while introducing a new approach to accommodate more transactions in each block.
According to an announcement on Tuesday, $BNB Chain confirmed the activation of Pasteur on the BSC mainnet. The upgrade enhances the security of the network’s bridge, staking, and governance mechanisms, while increasing block capacity without altering the 450-millisecond block time.
The Pasteur upgrade incorporates three $BNB Evolution Proposals. BEP-682 prevents duplicate validator entries during cross-chain light-block verification, BEP-695 enhances controls on validator key rotation, slashing, and governance voting, and BEP-675 modifies how builders submit blocks to validators.
The upgrade ensures validators are not duplicated in bridge approvals, eliminates old validator keys, restricts voting from certain addresses, and aims to increase transaction throughput during peak times.
Pasteur Enhances Block Capacity
Previously, BSC’s block-building process required builders to execute transactions before submitting a proposed block, which was then re-executed by validators before being signed. $BNB Chain noted that this redundant process sometimes led to underfilled blocks within the 450-millisecond window.
With BEP-675, builders can submit pre-executed blocks for validation, allowing validators to verify the block against consensus rules, sign, and broadcast it, and conduct full execution verification afterward. Alternatively, builders can continue using the previous method where validators execute transactions before signing.
In tests on QANet, a simulated environment reflecting BSC’s geographically dispersed validators, the new approach boosted throughput by approximately 88%, from 1,237 to 2,324 transactions per second. The average gas used per block increased from 46.35 million to 84.15 million, while maintaining the 450-millisecond block interval and 100-million gas limit.
$BNB Chain emphasized that the test results were based on controlled workloads and not actual mainnet data.
Pasteur follows previous upgrades focused on reducing block times. The Maxwell hard fork in June 2025 decreased BSC’s average block time from 1.5 seconds to around 0.8 seconds, and the subsequent Fermi upgrade further reduced it to 450 milliseconds, as reported by $BNB Chain.
