Ethereum Researchers Propose Quantum-Resistant Validator Upgrade

Ethereum researchers have proposed rebuilding the blockchain’s validator deposit contract as part of preparations to protect the network against future quantum-computing attacks.

The draft proposal focuses on the deposit contract, which allows users to lock Ether (ETH) to become Ethereum validators. It would introduce a mechanism enabling the network to eventually stop accepting its current BLS signature format and transition toward quantum-resistant cryptography.

Ethereum’s existing deposit system hard-codes the size of BLS cryptographic keys, making it incompatible with alternative signature formats. Under the proposed design, deposits could support different key sizes and would carry identifiers specifying which cryptographic system they use. BLS would receive the initial tag, while additional tags could accommodate future quantum-resistant alternatives.

Around 42.4 million ETH, valued at roughly $104 billion at current prices, was staked on Ethereum as of Wednesday. Those assets are currently secured through validator keys using BLS signatures.

BLS technology allows large numbers of validator signatures to be aggregated, helping Ethereum operate its consensus system efficiently. However, BLS relies on elliptic-curve cryptography, which researchers believe sufficiently powerful quantum computers using Shor’s algorithm could potentially break.

The proposal, currently an early draft awaiting review, has been suggested for designation as EIP-8394. It would initially keep BLS deposits active while allowing other cryptographic systems to be introduced alongside them. Ethereum developers could later permanently disable new BLS deposits without removing validators already using existing BLS keys.

The plan would also replace Ethereum’s older deposit-processing system with the newer framework already used for withdrawals and validator modifications.

The validator proposal complements EIP-8141, or Frame Transactions, which is being considered for Ethereum’s Hegotá upgrade later this year. That proposal could allow regular Ethereum accounts to change the cryptography used to authorize transactions without requiring users to move assets to new addresses.

Quantum security has become a growing Ethereum development priority following Google Quantum AI research published in March. The research outlined five potential quantum attack paths and estimated that more than $100 billion in assets across wallets, staking, smart contracts and layer-2 networks could face exposure. The Ethereum Foundation is reportedly targeting around 2029 for key protocol changes addressing the quantum threat.