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BNB Chain Sacrificed Speed for Quantum Resistance
Developers behind $BNB Chain have released the results of testing the network’s transition to post-quantum cryptography (PQC). The experiment confirmed the blockchain’s theoretical readiness for future quantum threats, but also revealed a significant decline in performance.
The team replaced standard ECDSA transaction signatures and BLS12-381 validator vote signatures with post-quantum mechanisms ML-DSA-44 and STARK aggregation.
Network Performance Declined Significantly
During testing, network throughput for simple transfers dropped by 40%, falling from 4,973 TPS to 2,997 TPS.
For mixed workloads, the decline was approximately 35%.
The main scalability bottleneck proved to be the sharp increase in data volume:
- the size of a typical transaction increased from 110 bytes to 2.5 KB;
- block size expanded from 130 KB to approximately 2 MB.
Developers noted that the primary issue lies in bandwidth limitations caused by the dramatically heavier blocks.
What the Developers Changed
Additional technical details were published on GitHub.
As part of the Proof-of-Concept implementation, the team:
- introduced a new transaction type called PQTxType (0x05);
- created an on-chain PQ Registry (0x70) for storing public keys;
- replaced linear BLS aggregation with pqSTARK, allowing validator signatures to be compressed at a 43:1 ratio.
The choice of the ML-DSA-44 standard was based on achieving a balance between security and key size.
BNB Chain Became One of the First Networks to Publicly Test PQC
The experiment demonstrated that transitioning to quantum-resistant protection is technically possible even for a large EVM-compatible blockchain.
The primary obstacle to adoption was not consensus itself, but rather the increased network load caused by larger data structures.
$BNB Chain became one of the first platforms to publicly demonstrate the real-world trade-offs involved in migrating to post-quantum cryptography.
Other Blockchains Are Also Preparing for the Quantum Era
Ripple recently introduced a roadmap for protecting the XRP Ledger against quantum threats.
The initiative includes two parallel strategies — gradual migration and an emergency response scenario in the event of Q-day, the moment when quantum computers become capable of breaking classical cryptography.
Ethereum Foundation has also published a roadmap for protecting the Ethereum network from quantum computers.
The plan includes four hard forks scheduled through 2029.
The Bitcoin community is also actively debating the issue. Developer Jameson Lopp and a group of experts introduced a draft proposal known as BIP-361.
The proposal would freeze coins considered vulnerable to quantum-computing attacks.
Quantum Risks Are No Longer Purely Theoretical
Earlier in April, independent researcher Giancarlo Lelli successfully calculated a 15-bit ECC cryptographic key using a publicly accessible quantum computer.
