Ethereum Researcher Proposes $0.07 Quantum Security Upgrade Without a Hard Fork

Highlights:

• Ethereum could add quantum-resistant account protection for about $0.07 without changing the network’s core protocol.
• Ethereum quantum security could become more accessible through the new SPHINCS design.
• Researchers are preparing for future quantum threats even though today’s blockchain networks remain secure.

Ethereum Foundation researcher Nicolas Consigny has proposed a system that allows Ethereum users to add post-quantum protection to their accounts. The account-level protection would cost roughly $0.07 per account. The design works through Ethereum’s existing infrastructure and does not require a hard fork. The proposal also avoids changes to Ethereum’s core protocol and network rules.

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Ethereum May Have Found A Cheap Quantum Defense

Ethereum $ETH researcher Nico (@ncsgy) says users could add quantum resistant account protection for roughly $0.07 per account without waiting for a hard fork.

The proposal relies on wallet level smart contract logic rather than a… pic.twitter.com/d7Ar6qcybQ

— BSCN (@BSCNews) June 15, 2026

Consigny presented the proposal through Ethereum’s privacy-focused Kohaku project. Users could deploy the protection directly to individual accounts without modifying the broader Ethereum network. As a result, Ethereum users could adopt post-quantum protection before developers introduce a dedicated network upgrade.

The proposal addresses the risk that future quantum computers could break the cryptographic systems that secure Ethereum accounts. Researchers have warned that future quantum computers could break the public-key cryptography that secures Ethereum, Bitcoin, and other blockchain networks. Therefore, Ethereum developers are exploring post-quantum security tools before quantum computing capabilities reach that stage.

The proposal has gained attention because it offers a deployable solution rather than a theoretical framework. Consigny said Ethereum can begin preparing accounts for a post-quantum future without waiting for protocol changes. Consigny also included a Verity formal proof in the project documentation. The Fable review, planned audits, and Verity formal proof aim to verify that the design works as intended before wider deployment.

New Design Makes Quantum Protection More Affordable

The proposal introduces SPHINCS-, an Ethereum-optimized version of the SPHINCS+ post-quantum signature standard. Researchers developed SPHINCS+ to protect digital systems from attacks by future quantum computers. The US National Institute of Standards and Technology later recognized SPHINCS+ as a post-quantum cryptography standard.

Ethereum can already start preparing accounts for a post quantum world, without waiting for a hard fork.

Today, it would be just 0.07$ .

Further audits incoming. Though I squeezed in a review with Fable before Uncle Sam crashed my party. Verity formal proof included for my…

— Nico (@ncsgy) June 13, 2026

SPHINCS+ generates large signatures that require significant computing resources during onchain verification. Those verification costs have limited adoption across public blockchain networks. Consigny reduced those costs by replacing the SHAKE256 hashing function with Ethereum’s native KECCAK256 hashing function.

Ethereum already relies on KECCAK256 for hashing operations throughout the network. Consequently, the Ethereum Virtual Machine processes KECCAK256 operations more efficiently than SHAKE256 operations. According to the research, Ethereum smart contracts could verify a post-quantum signature for roughly 150,000 gas. The lower verification costs could make Ethereum quantum Security tools more practical for everyday users and smart contracts.

The proposal also introduces optimized variants that reduce signature sizes. Those variants lower verification expenses for users and developers. SPHINCS- remains fully compatible with the Ethereum Virtual Machine and existing smart contract infrastructure. Developers can implement the design without adding new protocol features or precompiles.

Consigny designed SPHINCS as a bridge toward a future system known as leanSPHINCS. LeanSPHINCS aims to reduce verification costs through signature aggregation. The system plans to combine multiple signatures into aggregated proofs to improve efficiency.

Ethereum Quantum Security Moves Into Focus

Researchers are monitoring quantum computing because future machines could threaten blockchain security systems. Many major blockchain networks still rely on Elliptic Curve Digital Signature Algorithm cryptography. Ethereum, Bitcoin, and Solana all depend heavily on ECDSA for account security and transaction verification.

An April experiment demonstrated continued progress in quantum computing research. Project Eleven awarded researcher Giancarlo Lelli after he used a quantum computer to crack a 15-bit elliptic-curve key. Lelli derived the private key from its public key through a variation of Shor’s algorithm.

Meanwhile, Blockchain analytics firm Glassnode has examined how future quantum attacks could affect Bitcoin. The firm estimates that 1.92 million Bitcoin could be structurally exposed in a future quantum attack. That figure represents nearly 10% of Bitcoin’s total supply. Glassnode also estimates that 4.12 million BTC face operational risks because of key and address management practices.

Glassnode revealed that around 6.04M BTC nearly 30% of Bitcoin supply is theoretically at risk from future quantum threats because public keys are already visible on chain.

Whats even more interesting is that 4.12M BTC of that risk stems from preventable practices like address… pic.twitter.com/qznsfApz8P

— evans (@evans1vn) May 27, 2026

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