Ethereum co-founder Vitalik Buterin on Thursday outlined a roadmap to safeguard blockchains from the long-term risks posed by quantum computers — a move that comes shortly after the Ethereum Foundation launched a dedicated post-quantum research team to study the issue.
Although practical quantum computers capable of breaking modern cryptography do not yet exist, they could one day break the digital signature and cryptographic systems that protect Ethereum.
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A big part of the plan involves changing the way Ethereum validators sign and confirm blocks. Currently, they use a digital signature called BLS. In a world with powerful quantum computers, these signatures may eventually be cracked. Buterin suggested switching to “hash-based” signatures, which are considered more secure and resistant to quantum attacks.
Another area that needs updating is how Ethereum examines and stores large amounts of transaction data. The system it uses today relies on an encryption tool called KZG Commitment. Replacing it with a quantum-safe alternative is possible, Buterin said, but it would require a lot of behind-the-scenes engineering work and could make some parts of the system more complex.
For everyday users, the recommended fix revolves around a planned upgrade called EIP-8141. Simply put, this upgrade will make Ethereum wallets more flexible. Today, most wallets rely on a standard type of digital signature to approve transactions. EIP-8141 will allow accounts to switch to different types of signatures in the future, including signatures designed to be secure against quantum computers.
A similar problem exists with zero-knowledge proofs, an advanced cryptographic technique used by privacy tools and many layer 2 extension networks. Currently, it is much more expensive to verify quantum-safe versions of these proofs on Ethereum.
Buterin pointed to a long-term solution built into EIP-8141 called the “Verification Framework.” These will allow the network to bundle many signatures and proofs together and replace them with a single combined proof. Ethereum does not need to check each proof individually on the blockchain, but only needs to verify a compressed proof, thus helping to reduce costs.
Read more: Quantum threat becomes reality: Ethereum Foundation prioritizes security with LeanVM and PQ signatures