The developers of BNB Chain reported on the results of testing the network’s transition to post-quantum cryptography (PQC). The experiment confirmed the blockchain’s theoretical readiness for future threats, but revealed a significant decline in performance.
The team replaced standard transaction signatures ECDSA and validator vote signatures BLS12-381 with post-quantum mechanisms ML-DSA-44 and STARK aggregation.
During the trials, the network’s throughput for simple transfers decreased by 40% — from 4973 to 2997 TPS. For mixed loads, the drop was about 35%.
The main barrier to scaling was the sharp increase in data volume:
- the size of a typical transaction increased from 110 bytes to 2.5 KB;
- the block size grew from 130 KB to ~2 MB.
The developers noted that the main issue lies in the limitations of data transmission bandwidth due to the increased block size.
Additional technical details are available on GitHub. As part of the Proof-of-Concept, the team:
- implemented a new transaction type PQTxType (0x05);
- created an on-chain registry PQ Registry (0x70) for storing public keys;
- replaced linear BLS aggregation with pqSTARK, allowing validator signatures to be compressed by a factor of 43:1.
The choice of the ML-DSA-44 standard is due to its balance between security and key size.
The experiment in BNB Chain demonstrated that transitioning to quantum protection is possible at the level of a major EVM-compatible blockchain. The main barrier to implementation is not consensus, but the increased load on the network.
BNB Chain has become one of the first platforms to publicly demonstrate the practical costs of transitioning to PQC. Other blockchains are also actively preparing for the quantum era.
Ripple introduced a plan to protect the XRP Ledger from quantum threats. The initiative involves working in two parallel directions — gradual migration and an emergency scenario in case of Q-day (the moment classical cryptography is broken).
The non-profit Ethereum Foundation unveiled a roadmap to protect the network from quantum computers. The plan includes four hard forks by 2029.
The Bitcoin community is also actively discussing this issue. Developer Jameson Lopp and a group of experts presented a draft proposal BIP-361. The initiative suggests freezing coins vulnerable to quantum computers.
Back in April, independent researcher Giancarlo Lelli calculated a 15-bit cryptographic key on ECC using a publicly available quantum computer.