Ethereum accounts could gain post-quantum protection for as little as $0.07 per transaction under a new proposal from the Ethereum Foundation’s Kohaku project.
Ethereum (ETH) accounts could be shielded against future quantum-computing attacks for as little as $0.07 per transaction, according to Nicolas Consigny, lead of the Ethereum Foundation's Kohaku project. Consigny shared a paper on June 14 proposing a lower-cost path to post-quantum protections that does not require waiting for a hard fork.
The proposal adapts SPHINCS+, a post-quantum signature standard developed by the US National Institute of Standards and Technology (NIST), to operate more efficiently on Ethereum. The adapted scheme is called "SPHINCS-" and is designed to lower on-chain verification costs without requiring a protocol change or precompile.
Source: Nico
Consigny described SPHINCS- as an interim measure bridging toward a longer-term system called "leanSPHINCS," which aims to cut verification costs further through aggregation. The goal is to give Ethereum users a practical option for protecting their accounts before a dedicated hard fork is ready.
Why Quantum Risk Matters for Crypto Now
The proposal targets a specific vulnerability in Ethereum's Elliptic Curve Digital Signature Algorithm (ECDSA), which quantum computers could theoretically break using techniques that do not yet exist at scale. The concern is that such capabilities could emerge before the network completes a full protocol-level upgrade.
Interest in quantum threats to crypto networks grew in April 2026, when post-quantum startup Project Eleven awarded a prize to researcher Giancarlo Lelli for cracking a 15-bit elliptic-curve key using a quantum computer. Lelli derived a private key from its public counterpart using a variant of Shor's algorithm, a quantum computing technique that poses a theoretical risk to the cryptography securing Bitcoin (BTC) and other networks.
BTC keys are 256 bits long, far beyond the 15-bit key that was broken, but the result renewed discussion about long-term cryptographic risk. According to Glassnode, approximately 1.92 million BTC, close to 10% of total supply, are considered structurally unsafe under a future quantum attack scenario. An additional 4.12 million BTC, or 20.6% of supply, are classified as operationally unsafe due to key or address management practices.
Related Article: AI Is Accelerating the Quantum Threat to Crypto Security, Researchers Warn
Glassnode estimates the remaining 69.8% of supply, approximately 13.99 million BTC, is not currently exposed to quantum risk. That figure is broadly consistent with an Ark Invest estimate from March 2026, which placed 65% of the Bitcoin supply in the safe category.
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