As quantum ‘Q-Day’ jumps to 2029, Ethereum faces a new fight over what to do with coins left in old wallets

The realistic quantum threat to Ethereum, or "Q-Day," is now framed around a 2029 horizon, according to Google's planning, accelerating the need for post-quantum readiness. The Ethereum Foundation's roadmap prioritizes migrating exposed surfaces, starting with user accounts (EOAs), then high-value operational keys at exchanges and bridges, followed by governance multisigs and validator keys. Account abstraction (EIP-4337) is the primary execution-layer path for users to upgrade authentication without a chain reset, though adoption is still partial. The coordination challenge is significant, especially for bridges and custodians holding billions in value, where operational discipline is already lacking. Furthermore, the community faces a politically charged decision regarding dormant coins whose public keys were exposed in old transactions; the EF suggests outcomes are either doing nothing or freezing vulnerable coins, estimating Ethereum's exposure at only 0.1% of supply, compared to Bitcoin's higher risk. The industry is already pricing in operational lag as a security risk, meaning credible migration timelines are becoming essential for capital retention well before a cryptographically relevant quantum computer arrives.

(Source：CryptoSlate)