Ethereum developers advance post-quantum readiness with deposit contract proposal

The Ethereum Foundation’s push to advance post-quantum readiness on the network’s mainnet got a new chapter on August 24 as a contributor presented a draft plan to integrate quantum-safe keys into the contract validators use to join the network. 

The proposal draft, if it scales all the stages through finalization, would set off a process where the network rebuilds and permanently switches off its current signature scheme. 

The urgency to turn draft plans into shipped code on Ethereum mainnet has escalated since advancements such as the March 2026 Google Quantum AI document that slashed the cost of breaking the 256-bit elliptic curve cryptography Ethereum uses by about 20 times, per ethereum.org. 

Those machines don’t exist anywhere in the world right now, but Ethereum is already planning for a future where they are, in the same way the National Institute of Standards and Technology (NIST) is too. The NIST plans to deprecate ECDSA by 2030 and disallow it by 2035.

What will the Ethereum post-quantum proposed contract change?

The one-line description in the draft proposal filed by Kevaundray Wedderburn, listing Thomas Coratger and Tom Wambsgans as co-authors, in the ethereum/EIPs repository presented a validator deposit contract with variable length, plus a mode to “irreversibly” retire BLS.

The way Ethereum runs right now, validators sign with a scheme that combines hundreds of thousands of signatures into one to keep consensus efficient. That is the BLS, which leans on elliptic curve pairings, per ethereum.org‘s quantum-resistance page. 

However, the problem is that a quantum computer running Shor’s algorithm can solve that kind of math. 

The Foundation’s fix is leanXMSS, a hash-based scheme that swaps out BLS’s 96-byte signatures with nearly 3,000 bytes.  

Length-flexible contracts and a switch that ends BLS for good resolve the new problem of fitting the new keys in a deposit contract with fixed-size fields. 

When will the proposal be voted on? 

Wedderburn’s proposal is not yet ready to be voted on, with the author specifying that the draft is unfinished and large portions are simply boilerplate covering EIP-7685 mechanics. Wedderburn added that the team still had to blend the draft with existing validator EIPs 7251, 7002 and 8282.

As Vitalik Buterin outlined in a February 2026 roadmap, the Ethereum developer ecosystem is working on four aspects to beef up its post-quantum readiness plan: 

• Validator BLS signatures, which cover deposit contracts
• KZG commitments behind data availability
• ECDSA signatures that guard ordinary accounts
• Zero-knowledge proof systems used by rollups

EIP-8141, another proposal to migrate users to quantum-safe signatures, is under consideration for the Hegotá upgrade and is expected to handle account-level protection through native account abstraction. 

Quantum readiness has been a 2026 priority

The Ethereum Foundation started January 2026 by naming a dedicated post-quantum team. Coratger, a co-author in Wedderburn’s deposit-contract draft, is a leader on that team. 

The Foundation attached a $1 million Poseidon Prize to hardening a hash function, on top of an earlier $1 million Proximity Prize. Justin Drake described all those efforts a “top strategic priority” at the time.

Core L1 quantum upgrades are targeted for around 2029, a date ethereum.org and Cryptopolitan both describe as a planning goal that could still move.

For now, the draft needs sign-off. The Foundation’s bot lists it as awaiting one more editor review, and an editor has asked that its placeholder number be reassigned to 8394 before it can advance.

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