BNB Chain Activates Pasteur Hard Fork on Mainnet

BSC continues to operate with its 450-millisecond block interval, while the new block-building mechanism is designed to improve how much transaction activity can fit within that short window.

Pasteur Strengthens BSC Bridge Security

One of the key changes comes through BEP-682, which modifies how BSC verifies light blocks submitted through cross-chain infrastructure.

The upgrade prevents duplicate validator entries from being counted separately when determining whether a submitted light block has reached the required approval threshold.

This means each validator must provide a distinct approval, reducing the risk that repeated entries could artificially increase the apparent number of validators supporting a cross-chain message.

BNB Chain has not said that the issue was previously exploited or linked it to any known asset loss. The change is therefore best viewed as a preventive security improvement to BSC's bridge verification process.

Cross-chain bridges remain an important security consideration across the blockchain industry because vulnerabilities in message verification, validator systems and smart contracts can expose large amounts of user funds.

Old Validator Keys Lose Authority

BEP-695 focuses on validator key rotation, penalties and governance.

Under the updated rules, when a validator replaces its operator key, the previous key loses its management authority. The change also prevents validators from avoiding pending penalties simply by changing their keys.

The upgrade further strengthens governance controls by preventing restricted addresses from using offchain signatures to participate in votes.

This adds another layer of protection around BSC's validator and governance infrastructure.

New Block-Building Route Could Increase Capacity

The third major component, BEP-675, introduces an optional block-building route for specialist builders.

Previously, both the block builder and validator could need to execute transactions before the validator signed the proposed block. Because BSC operates with a short block interval, repeating that execution could limit how many transactions were included.

Under the new approach, builders can submit blocks they have already executed. Validators can then verify the proposal against consensus rules, sign and broadcast it, followed by full execution verification.

Builders can still use the existing process, while the new route can be enabled through BSC's RPC interface.

BNB Chain Reports 88% Throughput Improvement in Testing

BNB Chain tested the new block-building route on QANet, an internal environment designed to simulate geographically distributed validators.

The test increased reported throughput from 1,237 transactions per second to 2,324 TPS, representing an improvement of roughly 88%.

Average gas used per block also increased from 46.35 million to 84.15 million, while the 100-million gas limit and 450-millisecond block interval remained unchanged.

However, these figures came from controlled testing and do not represent guaranteed mainnet performance.

Live block utilization and validator data will ultimately determine whether the improvement translates into sustained higher throughput on BSC.

BNB Chain — Pasteur Hard Fork Details

Node Operators Required a Client Upgrade

BSC node operators were required to upgrade to client version 1.7.7 ahead of the hard fork.

Operators also needed to remove the deprecated EnableBAL configuration field. BNB Chain warned that leaving the field in configuration files could prevent updated clients from starting correctly.

The requirement highlights that Pasteur is a network-level upgrade rather than simply an optional software improvement.

What Pasteur Means for BNB Chain

Pasteur does not increase BSC's block gas limit or shorten its existing 450ms block time.

Instead, the upgrade focuses on making better use of the existing block-production window while improving security around bridges, validators and governance.

The most important metrics to watch following activation include:

• Mainnet transaction throughput

• Block utilization

• Validator performance

• Missed-block rates

• Adoption of BEP-675 by builders

• Cross-chain security performance

If validators and builders widely adopt the new block-building route, BSC could potentially process more transactions without changing its current block interval.

Conclusion

The BNB Chain Pasteur hard fork represents another step in BSC's effort to improve both network security and performance.

The upgrade strengthens cross-chain validator verification, removes authority from outdated validator keys and introduces a new block-building mechanism designed to reduce duplicated execution.

BNB Chain's controlled testing showed an 88% increase in throughput, but the real test will come from mainnet data. If the new architecture performs as expected under real network demand, Pasteur could help BSC handle higher transaction activity while maintaining its existing 450-millisecond block schedule.