Which Bitcoin Wallets Are at Risk From Quantum Computers? 6.9 Million BTC Have Exposed Keys

Millions of Bitcoin are sitting in addresses where a quantum computer could drain them without warning, and whether your own coins are exposed comes down to two details most holders have never checked.

Google Quantum AI’s March paper found about 6.9 million Bitcoin in addresses where the full public key is already visible on-chain, exposed to what researchers call an at-rest attack.

Some of those coins are held in early keys nobody can move. The rest belong to holders who could act if they knew which addresses were affected. So how do you know whether your own coins are exposed?

6.9 Million Bitcoin Held in Addresses With Visible Public Keys

An at-rest attack targets a key already published on the chain rather than one briefly revealed during a transaction, so a future quantum computer would have unlimited time to derive the private key offline and empty the wallet.

The same paper flagged about 20.5 million Ethereum (CRYPTO:ETH) in similarly exposed accounts. Every standard Ethereum account publishes its public key the first time it signs a transaction, and most active balances already have.

The exposure covers roughly a third of Bitcoin’s circulating supply and about a sixth of Ether’s, and it doesn’t depend on the owner doing anything wrong. The address type a coin was created under and whether that address has ever been used set the exposure between them.