BNB Chain quantum-safe test passes; transactions ~40% slower

BNB Chain tested quantum-resistant signatures this week. The new signing method worked functionally, but signature size increased from 65 bytes to about 2,420 bytes and cross-region stress-test throughput dropped from 4,973 transactions per second to 2,997 TPS.

The roughly 35-fold increase in signature size raised per-transaction data, causing blocks to fill faster and increasing transmission time between regions. The reduction in raw transaction throughput led the project to miss its stated TPS targets for the year.

Smart contract transactions were less affected because they already include larger amounts of data, so their relative slowdown was smaller than for simple transfers.

Validator voting remained efficient due to a compression technique that aggregates six votes into a single proof. Combined vote data fell from about 14.5 kilobytes to roughly 340 bytes, a roughly 43-to-1 reduction, which kept most block confirmations to about two slots.

In cross-region tests the slowest 1% of confirmations took up to 11 slots, a delay the report attributes to longer propagation times for larger blocks.

The team will not enable the quantum-safe code for all users until it resolves the increased data and latency issues. The report also noted that other parts of the system still need post-quantum upgrades and that some work will require coordination with the wider Ethereum developer community.

The report noted: “Post-quantum readiness is achievable on BSC today, with data size growth and network constraints as the main trade-offs.”