Is your Bitcoin exposed to the quantum threat?
Paste a Bitcoin address and check whether its public key is already visible on the blockchain — the one thing a future quantum computer could exploit. Everything runs in your browser: the address never touches our servers.
Why does this matter?
Your Bitcoin is protected by an elliptic-curve signature. Deriving the private key from the public one is impossible for a normal computer, but a large quantum computer could do it with Shor's algorithm. The key point: only what is already visible is at risk. A modern unspent address shows only a hash; nothing to attack.
When does your public key get exposed?
When you spend
Every time you send from an address, you sign — and that signature reveals your public key forever. This is why reusing addresses is dangerous.
Taproot addresses (bc1p)
They publish the public key directly in the output, whether spent or not.
Old P2PK addresses
The 2009-2011 ones (Satoshi's era) used the public key as the address itself: exposed from day one.
What to do today (no panic)
- Don't reuse addresses. A fresh address for every payment.
- Keep funds in modern, unspent addresses. They only show a hash: today that's the safest place.
- Don't panic-sell. No quantum computer can do this today, and Bitcoin is already preparing the migration (BIP-360).
- Beware miracle 'quantum-safe coins'. If the sales pitch is fear, it's marketing.
- Migrate when the time comes. When wallets support the new resistant addresses, it's just one more hygiene step.
Understand the quantum threat in depthWhat BIP-360 and BIP-361 are, how many bitcoins are exposed and what comes next.
Read the full guide →
Informational tool. Not financial or security advice. The check is based on public blockchain data via mempool.space.