BNB Chain schedules security-focused Pasteur hard fork for Aug. 25

BNB Chain has scheduled its Pasteur hard fork for Aug. 25, introducing three changes intended to strengthen cross-chain transfers, tighten validator controls, and raise tested transaction capacity from 1,237 to 2,324 transactions per second.

BNB Chain said in an Aug. 14 announcement that Pasteur will go live on BNB Smart Chain at 2:30 a.m. UTC on Aug. 25 after running on its test network since July 21.

Node operators must install BSC software version v1.7.7 before the activation time. The network also instructed operators to remove an outdated setting called EnableBAL from their configuration files because the updated software will not start if it remains in place.

Pasteur includes three proposals: BEP-682, BEP-695, and BEP-675. The first two address security and validator permissions, while the third changes how transactions are processed when new blocks are prepared.

Pasteur will strengthen BNB Chain bridge checks

BEP-682 changes how BNB Smart Chain confirms transfers arriving from another blockchain. Before accepting the assets, BSC checks whether enough validators from the sending network have approved the transfer.

BNB Chain said the current process does not prevent the same validator from appearing several times in the approval list. A carefully prepared request could therefore count one validator’s approval more than once, allowing a transfer to pass with fewer separate approvals than the rules require.

Pasteur will reject repeated validator entries. According to the network, cross-chain transfers will then need approval from the proper number of separate validators before BSC accepts them.

The proposal addresses a specific weakness in BNB Chain’s transfer checks, although the network did not say the issue had been used to steal funds.

Cross-chain security has received added attention after attacks on several third-party bridges. In July, a Cardano-to-BNB Chain bridge operated by Wanchain reportedly lost about 515 million NIGHT tokens, valued at roughly $9 million at the time.

Security firm BlockSec said the reported attack may have involved a weakness in the messages sent to validators for approval. Midnight Foundation later said the incident affected Wanchain’s third-party bridge and did not involve the Midnight Network itself.

Separately, crypto.news reported in August that cross-chain bridge attacks had caused more than $4 billion in losses since 2021. The report identified stolen validator keys and poor transfer checks as among the weaknesses used in major incidents.

BNB Chain has not connected Pasteur to the Wanchain attack or any other recent exploit. Its announcement presents BEP-682 as a direct correction to the approval system used for transfers entering BSC.

Old validator keys will lose access

A second proposal, BEP-695, changes what happens when validators replace the digital keys they use to manage their duties on the network.

Changing keys is a routine security measure, but BNB Chain said an old key could continue to hold management rights after its replacement. Pasteur will remove those rights once a validator starts using a new key.

Pending penalties will also remain attached to the validator after a key change. According to the network, a validator facing removal for breaking network rules will no longer be able to avoid the process simply by replacing its key.

The same proposal closes a separate gap in BSC governance. Blacklisted addresses are already prevented from voting directly, but BNB Chain said they could still take part by signing a vote away from the blockchain and asking another account to submit it.

After Pasteur, the restriction will also cover votes submitted through signed messages. BNB Chain said the change will prevent blacklisted addresses from using an indirect route to participate in governance decisions.

Network operators have faced similar update requirements during earlier BSC upgrades. Before the Osaka/Mendel hard fork in April, BNB Chain issued a mandatory software notice telling operators to install version v1.7.2 and remove old settings to prevent their nodes from falling out of sync.

Osaka/Mendel introduced nine network proposals covering transaction limits, stability, and the process used to confirm transactions. The upgrade followed Fermi, which reduced BSC’s block time to 0.45 seconds in January.

Pasteur will keep that block time unchanged. Instead of making blocks arrive faster, the latest upgrade is designed to place more transactions inside each one.

Internal tests raised capacity to 2,324 TPS

BNB Chain said block builders and validators currently repeat some of the same work when preparing a block of transactions.

A builder first processes the transactions and sends the completed block to a validator. The validator then processes the same transactions again before approving the block, leaving less time to add as many transactions as the network can support.

BEP-675 will allow a builder to send a block that it has already processed. The validator can check that the block follows network rules, approve it, and complete a deeper review afterward.

During tests on QANet, an internal environment designed to resemble BSC’s main network, the time validators spent on the immediate check fell from 125 milliseconds to 15 milliseconds.

Transaction capacity rose from 1,237 TPS to 2,324 TPS while the block time remained at 450 milliseconds. BNB Chain also kept the maximum amount of computing work allowed in each block unchanged during the test.

Average use of each block’s available capacity increased from 46.35% to 84.15%. According to the network, the test suggests BSC could handle busier periods by using more of the space already available rather than increasing block speed.

BNB Chain cautioned that the figures came from controlled tests and do not represent confirmed results on the live network. The new block-building method will not begin automatically when Pasteur activates because builders will receive additional time to prepare their systems.

Regular users and most application developers will not need to take any action. Node operators and block builders are the groups responsible for completing the software changes.

U.S. investors have exposure through a listed BNB fund

The upgrade also has relevance for American investors who hold BNB through a regulated investment product. Securities and Exchange Commission records show that shares of the VanEck BNB ETF are registered for trading on Nasdaq under the ticker VBNB.

The fund’s registration statement became effective on May 27. Its stated purpose is to track the price of BNB, minus the fund’s operating expenses.

According to an Aug. 7 SEC filing, VanEck Digital Assets appointed BitGo Bank & Trust as a second company responsible for safeguarding the fund’s BNB holdings. BitGo is a nationally chartered bank supervised by the Office of the Comptroller of the Currency.

The agreement allows BitGo to hold BNB for the fund and process deposits or withdrawals between the fund’s account and public blockchain addresses. VanEck’s filing states that the fund retains ownership of the tokens and that BitGo must keep them separate from assets belonging to its other customers.

BitGo cannot lend, pledge, or reuse the BNB unless the fund gives permission or the law requires it. The custody agreement was signed on Aug. 5 and disclosed to the SEC two days later.