A proposal called SPHINCS- could let Ethereum users protect their accounts against quantum-computing attacks for as little as 7 cents per transaction, according to the lead developer behind Ethereum's Kohaku project. The plan is positioned as a near-term patch while the network works toward a more permanent post-quantum solution.
What Post-Quantum Signatures Are — and Why They Matter
A digital signature is the cryptographic proof that you, and only you, authorized a transaction. The signatures Ethereum currently uses rely on mathematical problems that classical computers cannot solve in any practical timeframe. Quantum computers, if they reach sufficient scale, could crack those same problems — potentially allowing an attacker to forge signatures and drain wallets.
Post-quantum signatures are a different family of cryptographic schemes designed to remain secure even against quantum hardware. SPHINCS- is one such scheme. The "post-quantum" label is not marketing shorthand; it refers to a specific class of algorithms that security researchers believe will hold up against quantum attack methods.
What the On-Chain Data Claim Actually Says
The figure that matters here is the 7-cent cost cited by the Kohaku lead. That number represents the price of running post-quantum signature verification on Ethereum — the computation the network must perform to confirm a transaction is legitimate under the new scheme. Cheaper verification matters because high costs translate directly into higher fees for ordinary users, which historically has been enough to kill adoption of even technically sound proposals.
The source does not specify what network conditions or fee assumptions underlie the 7-cent figure, so readers should treat it as a best-case estimate until more detail is published.
An Interim Fix, Not the Final Answer
The Kohaku lead frames SPHINCS- explicitly as a stopgap. Ethereum is pursuing a longer-term post-quantum solution in parallel, and the SPHINCS- proposal is designed to reduce verification costs while that broader work continues. That framing is worth noting: a protocol announcing an interim measure is implicitly acknowledging that quantum risk is real enough to act on now, even before the comprehensive fix is ready.
For $ETH holders, the practical question is whether 7 cents per transaction is low enough to encourage meaningful adoption of quantum-resistant accounts — or whether it remains a feature only the security-conscious will bother enabling.