BNB Chain quantum upgrade cuts throughput by 40%

BNB Chain's quantum-resistant cryptography tests cut throughput by 40%-50% due to much larger data sizes, revealing major network scalability challenges.

BNB Chain has successfully completed extensive testing of post-quantum cryptography upgrades on its smart contract network. The upgrade replaces ECDSA transaction signatures with the ML-DSA-44 standard and adopts pqSTARK for consensus vote aggregation. This migration, standardized by NIST, maintains compatibility with existing addresses, wallets, and developer tools, minimizing disruption for users and infrastructure. However, the shift to quantum-resistant signatures dramatically increased signature size from 65 bytes to 2,420 bytes. Consequently, transaction sizes grew from 110 bytes to about 2.5 KB, and block sizes expanded from around 110–130 KB to nearly 2 MB. This led to a 40%–50% drop in transaction throughput, with native transfer TPS falling from 4,973 to 2,997 in tests. The main bottleneck is now network data propagation rather than consensus protocol efficiency. While pqSTARK achieved a 43:1 compression ratio to manage validator overhead, cross-region finality times increased due to larger block propagation. The tests show quantum-resistant blockchain deployment is feasible, but significant network bandwidth and scalability challenges remain before production rollout.