BNB Chain researchers say the hardest part of moving blockchains toward post-quantum security may not be consensus at all. The larger problem is data size. In their tests, switching to quantum-resistant signatures drove throughput down by 40% to 50%, while cross-region finality delays became more visible under heavier network conditions.
The study examined how BSC could migrate to post-quantum security by combining ML-DSA-44 transaction signatures with pqSTARK aggregation. The goal is to replace existing cryptographic schemes such as ECDSA and BLS, which could eventually be broken by future quantum computers. Researchers said post-quantum readiness is technically possible today, but the trade-off on scalability is substantial.
Transaction size jumps from 110 bytes to nearly 2.5 KB
The report lays out the scale of the change in concrete terms. A standard BSC transaction currently averages about 110 bytes under existing encryption methods. After moving to ML-DSA-44, the average transaction size rises to nearly 2.5 KB. Under similar transaction loads, block size also expands from roughly 130 KB to almost 2 MB.
That increase feeds straight into network performance. Larger blocks take longer to propagate across validator nodes, which raises pressure on data transfer across decentralized infrastructure. Researchers said the main bottleneck came from the need to move much larger amounts of information through the network, not from a breakdown in consensus efficiency itself.
pqSTARK helps validators, but propagation still slows the network
According to the study, pqSTARK aggregation reduced validator signature data by nearly 43 times. That helped preserve validator-side efficiency even as transaction sizes grew. So the validation layer held up. The network layer did not move as easily.
The report also explained why the team selected ML-DSA-44 instead of larger post-quantum variants. Researchers said it offers strong security while keeping signatures smaller and verification faster, making it more practical for high-throughput environments such as BSC.
Quantum attacks are not here yet, but upgrade pressure is building
The researchers stressed that quantum computers still cannot realistically break Bitcoin or BSC encryption systems today. Even so, the study points to a clear infrastructure challenge for public blockchains. If networks eventually shift to post-quantum cryptography, maintaining transaction speed and scalability will likely require major upgrades well beyond the signature scheme itself.