Ethereum co-founder Vitalik Buterin on Thursday laid out a roadmap for protecting the blockchain from the long-term risks posed by quantum computers – a move that comes shortly after the Ethereum Foundation created a dedicated post-quantum research team to study the issue.
Although there are no quantum computers yet that can break modern cryptography, they could one day decipher the digital signatures and cryptosystems that secure 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 type of digital signature called BLS. In a world with powerful quantum computers, these signatures could eventually be broken. Buterin suggests moving to “hash-based” signatures, considered much more secure against quantum attacks.
Another area that could use an update is how Ethereum verifies and stores large batches of transaction data. The system it uses today relies on a cryptographic tool called KZG commitments. Replacing it with a quantum-secure alternative is possible, Buterin said, but it would require significant engineering work behind the scenes and could make some parts of the system more complicated.
For everyday users, the proposed fix centers around a planned upgrade called EIP-8141. Simply put, this upgrade would make Ethereum wallets more flexible. Today, most wallets rely on a standard type of digital signature to approve transactions. EIP-8141 would allow accounts to move to different types of signatures in the future, including those designed to be secure against quantum computers.
There is a similar problem with zero-knowledge proofs, a type of advanced cryptography used by privacy tools and many Layer 2 scaling networks. Quantum-secure versions of these proofs are currently much more expensive to verify on Ethereum.
Buterin highlighted a longer-term solution built into EIP-8141, known as “validation frameworks.” These would allow the network to group together many signatures and proofs and replace them with a single combined proof. Instead of verifying each one individually on the blockchain, Ethereum would only need to verify a single compressed proof, which would help reduce costs.
Read more: Quantum threat becomes real: Ethereum Foundation prioritizes security with LeanVM and PQ signatures
