TLDR
- Ethereum researcher Nicolas Consigny proposes protecting accounts from quantum threats for just $0.07
- The solution, called SPHINCS-, adapts a US government post-quantum standard to Ethereum without needing a hard fork
- Google warned in March 2026 that quantum computers could break Ethereum’s encryption with fewer qubits than previously thought
- BlackRock and Moody’s both flagged quantum risks to crypto in early June 2026
- Nearly 10% of Bitcoin’s supply is considered structurally unsafe against a future quantum attack
Ethereum accounts could be protected from quantum computing threats for as little as $0.07 each, according to Nicolas Consigny, a researcher at the Ethereum Foundation.
JUST IN: Ethereum could quantum-proof accounts for as little as seven cents with SPHINCS- post-quantum signature verification. If scalable, it eases a future security upgrade path for $ETH. pic.twitter.com/TnU3OEwGj6
— Bpay News (@bpaynews) June 14, 2026
Consigny shared the proposal on June 14, 2026. It introduces a system called SPHINCS-, which adapts SPHINCS+, a post-quantum signature standard developed by the US National Institute of Standards and Technology.
The key advantage is that users could deploy this protection themselves, without waiting for a network-wide hard fork.
SPHINCS- is designed as a temporary fix. It reduces the cost of verifying quantum-resistant signatures on-chain, bridging the gap until Ethereum rolls out a longer-term solution called leanSPHINCS.
Ethereum’s current security relies on the Elliptic Curve Digital Signature Algorithm, or ECDSA. Quantum computers, if powerful enough, could break this encryption and expose wallets and transactions.
Why the Urgency Is Growing
In March 2026, Google researchers warned that fewer than 500,000 physical qubits could be enough to crack Ethereum’s encryption. That estimate is far lower than earlier projections, which put the number in the millions.
Google also identified five potential quantum attack vectors on Ethereum that could put more than $100 billion at risk.
Ethereum developers have plans to build a Post-Quantum Public Key Registry and roll out upgrades between 2026 and 2029. But those changes require broad coordination and are still years away.
Consigny’s proposal offers something users can act on now, without waiting for the network to catch up.
Industry Warnings Are Piling Up
On June 9, BlackRock warned that both Ethereum and Bitcoin need to speed up their quantum migration planning. A day earlier, Moody’s raised concerns about financial risks from delays in post-quantum cryptography, pointing out that competition with AI funding could slow progress.
Bitcoin faces its own exposure. Glassnode estimates that around 1.92 million Bitcoin, close to 10% of total supply, is structurally unsafe against a quantum attack. Another 20.6% is classed as operationally vulnerable due to key management practices.
That leaves roughly 69.8% of Bitcoin’s supply considered safe, broadly in line with an Ark Invest estimate from March 2026.
In April 2026, post-quantum startup Project Eleven awarded a prize to researcher Giancarlo Lelli for using a quantum computer to break a 15-bit elliptic-curve key. Bitcoin’s keys are 256 bits long, so a full break remains distant, but the direction of travel is clear.
Ethereum was trading at $1,665.49 on June 14, 2026, with a market cap of around $200.6 billion. The market has not reacted sharply, but pressure from major financial institutions to act is increasing.
Ethereum’s core developers are targeting 2029 for full quantum-resistant upgrades. Until then, low-cost stopgap solutions like SPHINCS- may be the most practical option available to users.
