A proposed Ethereum wallet scheme would make it harder for a future quantum computer to connect stealth-payment announcements with recipients, while leaving spending keys and transfer details exposed.
The ERC-8441 draft proposal defines schemeId 3 for ERC-5564, the stealth-address framework. It derives a payment secret from ML-KEM-768 and secp256k1 elliptic-curve Diffie-Hellman (ECDH), combining the two cryptographic methods. Its purpose is to reduce the chance that a future quantum computer could use public announcements to identify a recipient.
That protection is conditional. The proposal assumes ML-KEM-768 stays secure and that its ciphertexts satisfy an anonymity property known as ANO-CCA; it notes that FIPS 203 does not claim that property. Recipients may benefit if both assumptions hold, while people scanning announcements would need to run ECDH and ML-KEM decapsulation for each one.
The scheme addresses a weakness in the existing approach, which relies on secp256k1 ECDH. A sufficiently capable quantum computer could compromise those keys and expose recipient links preserved in permanent public announcement records. ERC-8441 would not conceal transfers that fund stealth addresses: transaction timing, amounts or later sweeps could still connect activity. Spending would also remain controlled by a secp256k1 key that a quantum attacker could break.
The draft is designed to work with the existing ERC-5564 announcer and ERC-6538 registry interfaces, without a new contract or consensus change.
Local-node measurements show schemeId 3 registration at 964,737 gas, versus 115,310 for schemeId 1. Announcements cost 69,330 gas under schemeId 3 and 28,313 under schemeId 1. The draft notes that the schemeId 3 announcement figure uses the EIP-7623 calldata floor, while schemeId 1 uses standard pricing, limiting a direct comparison. The higher measured gas costs and added scanning work are tradeoffs for the proposed privacy layer.
A separate draft, EIP-8450, is titled “Post-Quantum Consensus Key Registry” and covers Ethereum validators and builders.
