Ethereum ETH
An EVM address is the last 20 bytes of the Keccak-256 hash of the secp256k1 public key, so an account that has only received funds has not revealed its key. The first transaction an externally owned account sends carries an ECDSA signature from which the public key is recovered, and it stays exposed for the life of the account. Contracts and smart accounts have no key of their own; exposure sits with whichever keys are authorised to control them. The account model encourages address reuse, so most ETH sits in accounts that have already sent at least once.
Not live. The Ethereum Foundation's plan is signature agility through account abstraction rather than a protocol-wide key swap: EIP-8141 (Frame Transactions, native account abstraction) is being considered for the Hegota upgrade in the second half of 2026, letting an account switch to a post-quantum signature scheme individually. pq.ethereum.org tracks the full roadmap (PQ signature precompiles, PQ transactions, PQ aggregation) with a stated goal of quantum resistance across execution, consensus and data layers by December 2029. STARK-based rollups already rely on hash assumptions, but EOAs on L1 remain secp256k1 today.
Where the exposure number comes from
Quantum Horizon: An evaluation of quantum computing as a threat to Bitcoin and Ethereum (Gershteyn and Alber, arXiv 2606.14484), as of 2026-06-04. Share of ETH held in externally owned accounts that have already sent a transaction, reconciled top-down (supply minus staked and contract-held ETH) and bottom-up from on-chain components; the paper gives 50 to 65% (61 to 79M ETH), most defensibly 55 to 60%, recorded here as the midpoint of that tighter range.
Deloitte's earlier measurement (page undated, references 2021 market data) found over 65% of all Ether in accounts with a revealed public key, counting addresses with at least one outgoing transaction. The Google Quantum AI, Ethereum Foundation and Stanford whitepaper (arXiv 2603.28846, 30 March 2026) does not give a supply share; CoinDesk's coverage cites it as saying the top 1,000 wallets, about 20.5M ETH, have exposed keys.
Sources
- Quantum Horizon (arXiv 2606.14484) accessed 2026-09-17
- Deloitte: Quantum risk to the Ethereum blockchain accessed 2026-09-17
- ethereum.org: Post-quantum cryptography on Ethereum accessed 2026-09-17
- Google Research blog: Safeguarding cryptocurrency by disclosing quantum vulnerabilities responsibly accessed 2026-09-17
- arXiv 2603.28846: Securing Elliptic Curve Cryptocurrencies against Quantum Vulnerabilities accessed 2026-09-17
- CoinDesk: Google warns five quantum attack paths could put $100 billion on Ethereum at risk accessed 2026-09-17