Ethereum's Kohaku lead says the network can protect user accounts against quantum-computing attacks for just seven cents, pointing to a proposal built around the SPHINCS+ signature scheme as a near-term solution. The proposal's stated goal is to reduce the cost of post-quantum signature verification while Ethereum builds toward a longer-term fix. That price point, if it holds, would make quantum resistance accessible to ordinary users rather than an expensive edge case.
What SPHINCS+ Does and Why Cost Has Been the Barrier
Post-quantum signatures replace the cryptographic assumptions underpinning standard Ethereum accounts — assumptions that a sufficiently powerful quantum computer could eventually break — with schemes designed to resist such attacks. The catch has always been cost: post-quantum signature schemes carry heavier computational overhead than the ones Ethereum currently uses, and heavier computation translates to higher fees for users. The SPHINCS+ proposal targets that specific problem, aiming to bring verification costs down to a level that does not price out ordinary account holders.
The Kohaku lead's seven-cent figure puts a concrete number on what that reduction looks like in practice. Whether it survives contact with real network conditions is a separate question the proposal has not yet answered.
A Bridge, Not the Final Architecture
The framing here is deliberate: SPHINCS+ is positioned as an interim measure, not Ethereum's permanent post-quantum solution. The network is already working toward a more comprehensive upgrade, and SPHINCS+ is designed to provide cover during the transition window — the gap between now and whenever that longer-term solution is production-ready.
That gap is not trivial. Harvest-now-decrypt-later attacks, in which an adversary copies encrypted data today and decrypts it once quantum hardware matures, mean preparation timelines start well before quantum computers capable of breaking current cryptography actually exist. An interim option priced at seven cents per account gives users a way to act rather than wait.
What the Proposal Leaves Open
The source does not specify a deployment timeline, the scope of account types covered, or how SPHINCS+ performs under full network load. Those are the variables that will determine whether seven cents is a durable benchmark or an optimistic scenario.
For now, the Kohaku lead's claim sets a cost floor that the broader post-quantum debate on $ETH can be measured against. If SPHINCS+ is adopted as a stepping-stone, that number becomes the baseline — and any more expensive solution that follows will need to justify the difference.