Binance's BNB beacon chain mainnet, operated by Binance, is set to introduce a new feature in an upcoming hard fork that will allow the blockchain to halt the production of new blocks under specific conditions. The upgrade, named "Zhang Heng," is scheduled to take place at block height 328,088,888 on July 19, according to BNB Chain's announcement on July 12. The hard fork will implement Binance Evolution Proposal BEP-255, which aims to achieve "on-chain asset reconciliation." This enhancement is intended to mitigate potential damage caused by vulnerabilities in cross-chain bridges, such as the BNB Smart Chain vulnerability discovered on October 7, 2022.
BEP-255, as described in a GitHub post, tracks user balance changes in each block and coordinates them to detect any anomalies. When a coordination error is identified, the blockchain will enter a panic state and stop producing new blocks. Binance stated that this action will impact downstream services, including the exchange's bridge, deposits, and withdrawals. However, Binance emphasized that such a drastic measure is necessary to safeguard the blockchain and its users. Restoring the blockchain will require a hard fork and the resolution of coordination errors, Which may involve blacklisting or correcting relevant accounts involved in exploitative behavior.
The hard fork also includes bug fixes to prevent rogue key attacks, a security issue where perpetrators generate valid aggregated signatures using private keys that do not belong to them. To address this bug, all existing voting addresses will be reset when the hard fork height is reached. Validators will need to add their voting addresses again. Additionally, the hard fork aims to enhance the chain's capability to handle more complex business rules and logic. Binance stressed that two-thirds of validators must switch to the v0.10.16 software version in advance to avoid complications.
BNB Chain provided detailed instructions for node operators to comply with the hard fork upgrade. However, BNB token holders using Binance.com or other centralized exchanges or cold wallets are not required to take any immediate action. On June 19, BNB Chain launch ed opBNB, a new Ethereum Virtual Machine-compatible layer-2 scaling solution based on the Optimism OP Stack.
