BNB Chain has tested a post-quantum cryptography upgrade for BSC, and the results are clear: it works, but at a cost. The trial showed that bigger signatures mean lower throughput.
On May 14, BNB Chain released its BSC Post-Quantum Cryptography Migration Report. The report said BSC tested post-quantum transaction signatures using ML-DSA-44 and also used pqSTARK for consensus vote aggregation. The good news? The migration can work with current BSC systems. It stays compatible with existing addresses, RPCs, SDKs, wallets, and transaction flows. So if the design moves into production, users and builders won’t need to change basic account formats.
BNB Chain stated, “Post-quantum readiness is achievable on BSC today.” But they added that data growth and network limits are the main trade-offs. They also noted that quantum computers are “not yet at a stage” where they can break current production cryptography in real-world systems.
BSC TPS drops as signature size jumps
The main problem came down to data size. Before the upgrade, transaction signatures were 65 bytes using ECDSA. After moving to ML-DSA-44, signatures jumped to 2,420 bytes. Full transaction size grew from 110 bytes to about 2.5 KB.
That extra load cut performance significantly. The report said block size grew to about 2 MB. Throughput dropped by about 40% to 50% in tests. In cross-region conditions, TPS fell by roughly 40%. This shows that network propagation becomes harder when blocks carry more data. Finality stayed at two slots in median cases, but wider gaps came from larger blocks moving across regions, not from a failure in the consensus design.
pqSTARK aggregation keeps validator load manageable
On the plus side, consensus vote aggregation performed better than the transaction layer. pqSTARK aggregation delivered about 43:1 compression. This helped keep validator overhead manageable during the test, which is a relief for those running nodes.
The upgrade did not cover every part of BSC’s cryptographic system. The report noted that peer-to-peer handshakes and KZG commitments remain outside the current migration. P2P migration would require ML-KEM, while KZG replacement would need wider coordination with the Ethereum ecosystem.
Speed roadmap faces new trade-off
The post-quantum test adds a new wrinkle to BNB Chain’s wider performance roadmap. BNB Chain has been targeting sub-150 millisecond finality and more than 20,000 TPS for complex transactions by 2026. That speed goal now has to fit with quantum-resistant security work. The latest test shows BSC can adopt ML-DSA-44 and pqSTARK, but larger signatures could make high-throughput targets harder without better data handling and network scaling. It feels like a classic trade-off: security now versus speed later.
