BSC Post-Quantum Upgrade Passes Test, But TPS Falls 40%

• BNB Chain has replaced its existing ECDSA encryption algorithm with ML-DSA-44.
• Test data showed signature size increased from 65 bytes to 2,420 bytes, while TPS dropped by ~40%.
• BSC’s latest test keeps the user-facing stack familiar while changing the cryptography.

BNB Chain released its BSC Post-Quantum Cryptography Migration Report, confirming that quantum-resistant transaction signing is feasible, but at the cost of significant performance overhead.

Replacing ECDSA With ML-DSA-44

The latest protocol replaces the existing ECDSA transaction signatures with ML-DSA-44 and moves consensus vote aggregation toward pqSTARKs, while maintaining compatibility with existing addresses, RPC endpoints, and wallets.

Notably, the data overhead recorded from the test shows that signature size rose from 65 bytes to 2,420 bytes, and cross-region TPS fell by about 40%. BNB Chain said network and data-layer scaling remain the main challenges before production deployment.

From an analytical point of view, the compatibility point is crucial, considering that a disruptive post-quantum migration would be hard for such a large EVM chain. That is because users, apps, wallets, exchanges, custodians, and infrastructure providers already depend on existing account formats and developer tooling.

What Really Changed?

However, BNB Chain’s report noted that the test keeps the user-facing stack familiar while changing the cryptography underlying transaction authorization and validator vote aggregation. For context, ML-DSA is a lattice-based signature scheme built on the Module Learning With Errors (MLWE) problem. It is the post-quantum digital signature standard published under NIST FIPS 204, designed to remain secure against a future large-scale quantum computer.

Why BNB Chain Chose the ML-DSA-44 Algorithm

According to the report, BNB Chain selected the ML-DSA-44 algorithm as the practical variant because of the importance of signature size and verification speed on a high-throughput blockchain. Meanwhile, the test provides clarity on why post-quantum upgrades are not simple swaps. 

BNB Chain noted in its report that quantum computing poses a long-term threat to elliptic-curve cryptography. It added that Shor’s algorithm can break discrete-logarithm-based systems, including ECDSA and BLS12-381, in polynomial time. 

However, it noted that the latest test marks the point where a production-ready defense is available and provides the foundation for the migration approach, including design choices, implementation details, and observed performance trade-offs.

The report further highlighted the main rationale for selecting the ML-DSA-44 variant, stating that it is based on a sufficient security margin, a signature size, which is the dominant onchain cost, and a verification that sits on the hot path.

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