BNB Smart Chain tests post-quantum crypto, throughput down 40%–50%

BNB Smart Chain developers ran large-scale tests of post-quantum cryptography on the live network, replacing the chain’s usual signature and consensus primitives with NIST-backed algorithms. The experiments measured changes in transaction size, block propagation and overall network throughput.

The test setup used ML-DSA-44, a lattice-based signature algorithm, for transaction signing and pqSTARK proofs to compress validator vote aggregation at the consensus layer. Developers applied the new primitives across comparable workloads to observe end-to-end effects on the network.

Average on-chain transaction packets increased from about 110 bytes to roughly 2.5 kilobytes. Block sizes rose from near 130 kilobytes to almost 2 megabytes under similar transaction loads. As a result, network throughput declined between 40% and 50%, with the largest drops occurring in cross-region propagation among geographically dispersed validators.

At the consensus layer, pqSTARK compression reduced the communication burden created by larger signatures. In one test case, six validator signatures that together measured about 14.5 kilobytes were compressed to a proof of roughly 340 bytes, a compression ratio near 43-to-1. Wallet addresses were left unchanged at 20 bytes and continue to use keccak-256 formatting, reducing the need for major changes to wallets, SDKs and RPC tools.

Developers chose the ML-DSA-44 parameter set to limit signature size while using a NIST-standardized approach to post-quantum security. The team noted that stronger parameter sets would produce larger signatures and further reduce performance. Researchers referenced current estimates that quantum computers able to break today’s elliptic-curve signatures remain years away as a factor in selecting a more compact post-quantum option.

The BNB Smart Chain team described the work as preparation for future cryptographic standards rather than a response to an immediate quantum threat. The tests demonstrate that NIST-backed post-quantum algorithms can operate within an existing blockchain architecture but require trade-offs in transaction size, block propagation time and throughput.