# Crypto Quantum Risk Report: Bitcoin and Ethereum Keys

> Crypto quantum risk explained with block-pinned data: Bitcoin and Ethereum funds whose public keys are exposed, BIP-360 and post-quantum migration plans.

Markdown copy of https://voltfincrypto.com/apps/crypto-quantum-risk-report

**Question:** How much crypto is exposed to a future quantum attack today, on Bitcoin and on Ethereum?

- Kind: Report in Voltfin Folio
- Topic: [Security and risk](https://voltfincrypto.com/topics/security)
- Chains: Bitcoin, Ethereum
- Status: Planned. The data is not published yet, so this page states no figure; each figure will open its receipt when it is.

A large enough quantum computer could break the signatures that protect Bitcoin and Ethereum accounts, and the coins it could reach are already visible: they sit behind public keys that are exposed on-chain. This report measures, at a pinned block on each chain, how much bitcoin and ether is in that position, and explains what the proposed migrations would change.

The two chains expose keys differently. On Bitcoin, exposure depends on the output type and on whether an address was reused; on Ethereum, every account that has sent a transaction has revealed its key through its signature, while accounts that have only received have not. Each edition is pinned to one block per chain, so its counts can be re-checked and compared with the next.

The report does not forecast when such a machine might exist. It sets out what is exposed and how exposure changes as new outputs and accounts are created. It also sets out what each proposal, from new output types to a sunset of old signatures, would do to those amounts.

## Blueprint

### What is exposed today

The bitcoin and ether behind exposed public keys at the pinned blocks, and the share of each chain's supply that represents.

Cites: Bitcoin with exposed keys; Ether in accounts with exposed keys; Exposed share of each chain's supply.

### Bitcoin by output type

Exposure split into P2PK, bare multisig, Taproot and reused addresses, with the hash-only types beside them.

Cites: Bitcoin per exposure class; Addresses per exposure class; Bitcoin in early P2PK outputs.

### Ethereum accounts that have signed

Ether in accounts that have sent a transaction against accounts that have only received, with contract accounts counted apart.

Cites: Ether in accounts with a nonce above zero; Ether in receive-only accounts; Ether in contract accounts.

### Is exposure growing or shrinking

How the exposed amounts changed since the last edition, and the share of new Bitcoin outputs created as Taproot in each month.

Cites: Change in exposed bitcoin since the last edition; Change in ether in exposed accounts since the last edition; Share of new outputs created as P2TR, by month.

### What the proposals would change

BIP-360, proposals to sunset old signature types and Ethereum's post-quantum account plans, each set against the amounts above.

Cites: Smart accounts and EIP-7702 delegations created per month.

## How it will be measured

- Bitcoin exposure classes come from the UTXO set at the report block: P2PK, bare multisig and P2TR outputs show keys directly, and reused P2PKH, P2WPKH, P2SH and P2WSH addresses revealed theirs in an earlier spend.
- On Ethereum, an externally owned account counts as exposed when its nonce is above zero at the report block, since every signed transaction reveals the public key; its ETH balance is read at the same block.
- Contract accounts, including smart wallets, are counted apart because they hold no key of their own; their owners' keys are exposed once those owners have signed.
- Every figure is pinned to one block per chain, named in the edition with its hash, and later editions are compared at their own pinned blocks.

## Data it needs

- `bitcoin_supply_daily` (to build): Bitcoin issued, supply by coin age band and by output script type (including coins whose public keys are already exposed), supply last moved long ago, and cost-basis measures.
- `account_abstraction_daily` (to build): ERC-4337 UserOperations, bundlers and paymasters, and EIP-7702 delegations per chain per day.
- Source: Bitcoin UTXO set at the report block, classed by scriptPubKey type and by whether an earlier spend revealed the address's key
- Source: Ethereum account nonces and ETH balances at the report block, from a state snapshot
- Source: eth_getCode at the report block, to separate contract accounts and EIP-7702 delegated accounts from plain accounts
- Source: Monthly counts of new Bitcoin outputs by script type, for the P2TR share
- Source: Proposal texts (BIP-360 and Ethereum research posts), cited by link and date

## Questions

### Is Bitcoin at risk from quantum computers?

Bitcoin's signatures would be breakable by a large fault-tolerant quantum computer running Shor's algorithm. Coins whose public keys are already on-chain would be exposed first; coins behind unrevealed key hashes would only be exposed while a spend reveals the key. The report measures how much bitcoin is in each group.

### Is Ethereum quantum resistant?

Ethereum's ordinary accounts sign with the same kind of elliptic-curve scheme as Bitcoin, and any account that has sent a transaction has revealed its public key. Proposed migrations would move accounts to post-quantum signature schemes, for example through smart accounts; the report tracks how much ETH remains in exposed accounts.

### What is post-quantum migration in crypto?

Migration means moving funds from keys a quantum computer could break to schemes it could not, such as hash-based or lattice-based signatures. It needs a protocol change that adds the new scheme and a transaction from every holder, which is why unmoved and lost coins are the hardest part.

### What does BIP-360 change?

BIP-360 proposes an output type, Pay-to-Merkle-Root, that keeps Taproot's script tree but drops the key-path spend, so no public key is written into the output. It does not add a post-quantum signature by itself; it removes one source of exposure for coins that move into it.

### Why would exposed coins be frozen?

Some proposals would phase out spending with old signature types after a deadline, so coins that were never migrated could not be taken by a future attacker. Others reject any freeze as confiscation. The report sets out what each option would mean for the exposed amounts it measures.

## Glossary

- **Exposed public key**: A public key that can be read on-chain, from an output script or a signed spend, which a quantum attacker would need to derive the private key.
- **Post-quantum signature**: A signature scheme, such as a hash-based or lattice-based one, designed to resist attacks by quantum computers.
- **Nonce**: On Ethereum, the count of transactions an account has sent; above zero, the account has revealed its public key.
- **Shor's algorithm**: A quantum algorithm that solves the discrete-logarithm problem behind elliptic-curve signatures, given a large enough fault-tolerant quantum computer.

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