BNB Chain recently conducted a trial for a post-quantum cryptography upgrade on its BSC network, and the results revealed significant performance trade-offs. The implementation of ML-DSA-44 signatures, designed to withstand quantum attacks, led to a notable increase in data load, reducing throughput by approximately 40% in testing scenarios.
The test, detailed in the BSC Post-Quantum Cryptography Migration Report released on May 14, demonstrated that transaction signatures grew from a mere 65 bytes to 2,420 bytes when switching from ECDSA to ML-DSA-44. Consequently, overall transaction size ballooned from around 110 bytes to roughly 2.5 kilobytes, causing block sizes to approach 2 MB and throughput to decline by 40% to 50% in controlled tests.
Despite these performance hits, BNB Chain emphasized that the migration remains compatible with current systems, including existing addresses, RPCs, SDKs, wallets, and transaction flows. This means users and developers wouldn’t need to alter basic account structures if the upgrade proceeds to production. However, the team acknowledged that quantum computers have not yet reached a stage where they can break existing production cryptography in real-world settings.
On a positive note, the consensus layer showed resilience thanks to pqSTARK aggregation, which achieved about 43:1 compression, helping to keep validator overhead manageable during the tests. Yet, not all cryptographic components were covered; peer-to-peer handshakes and KZG commitments were left out, as they would require broader ecosystem coordination for replacement.
The performance drop adds complexity to BNB Chain’s ambitious roadmap, which targets sub-150 millisecond finality and over 20,000 TPS for complex transactions by 2026. Balancing quantum resistance with high throughput will demand better data handling and network scaling solutions, as larger signatures pose a clear hurdle to achieving these speed goals.