博链BroadChain learned that at 22:30 on April 22, according to Bitcoinist, Coinbase's independent advisory committee released a position report on quantum computing and blockchain. The core viewpoint is clear: Bitcoin, Ethereum, and the broader blockchain industry should immediately begin formulating a quantum-resistant roadmap, rather than waiting for the arrival of fault-tolerant quantum computers. The report emphasizes that although large-scale fault-tolerant quantum computers will eventually be built, cracking current public-key cryptography requires equipment far beyond current capabilities. The threat is an engineering challenge, not an imminent market event.
The report points out that quantum-resistant protection needs to be implemented simultaneously at the consensus layer (validators signing blocks) and the execution layer (users signing transactions). The challenge is that the most ideal cryptographic alternatives are generally "heavier" than the elliptic curve systems currently used on-chain, especially when considering signature size, verification cost, and aggregation. For Bitcoin, the report distinguishes between UTXOs where the public key is still hidden behind a hash and outputs where the plaintext public key is already exposed on-chain. The latter, approximately 6.9 million BTC (including about 1.7 million older P2PK outputs), would be most vulnerable to "steal now, decrypt later" attacks if a quantum computer emerges.
Ethereum faces a broader range of quantum-sensitive aspects, including EOA transaction signatures at the execution layer, BLS validator signatures at the consensus layer, pairing-based proof systems in the EVM, and KZG commitments at the data layer. The report states that Ethereum's current direction is to transition both the consensus and execution layers to hash-based signatures, compressing the signature load through SNARK-based aggregation, with on-chain aggregated signature sizes around 128KB.
The report recommends a phased migration strategy rather than a sudden replacement. The consensus layer could set periodic quantum-resistant checkpoints, while the execution layer could adopt a "dual-signature" scheme, allowing users to sign using either the current elliptic curve scheme or a quantum-resistant scheme. This maintains current low costs while preserving the option to disable old signatures in the future. The authors conclude: "We firmly believe that large-scale fault-tolerant quantum computers will eventually be built... The time to start preparing is now."