BNB Chain has successfully trialed a post-quantum cryptography upgrade for the BNB Smart Chain (BSC), confirming that the network can be shielded against future quantum threats. However, the test came with a major performance penalty: transaction throughput dropped by roughly 40% due to much larger transaction data.
According to the BSC Post-Quantum Cryptography Migration Report released on May 14, the trial used ML-DSA-44 (Dilithium) for transaction signatures and pqSTARK for consensus vote aggregation. The design remained fully compatible with existing user-facing infrastructure including wallets, addresses, RPCs, SDKs, and transaction flows, meaning users would not need to alter account formats in a future migration.
The core trade-off was data size. Under the current ECDSA scheme, transaction signatures are only 65 bytes and full transactions around 110 bytes. After adopting ML-DSA-44, signatures ballooned to 2,420 bytes and transaction size to about 2.5 KB. As a result, blocks grew to roughly 2 MB, and throughput fell by 40–50% in test environments, with cross-region performance plunging about 40%. Finality stayed at two slots in median cases, but network propagation suffered.
Consensus-layer aggregation proved more efficient: pqSTARK delivered about 43:1 compression, keeping validator overhead manageable. Still, the upgrade did not cover peer-to-peer handshakes (which would require ML-KEM) or KZG commitments, the latter needing wider Ethereum ecosystem coordination.
“Post-quantum readiness is achievable on BSC today,” BNB Chain stated, while cautioning that network and data-layer scaling remain the main barriers to production deployment. The test adds a new layer to BNB Chain’s 2026 performance roadmap, which targets sub-150ms finality and over 20,000 TPS for complex transactions — goals now complicated by quantum-resistant security requirements.
