Is your bitcoin exposed to quantum computers?
Some coins are protected by their address type. Others have their public key sitting on-chain, harvestable by a future quantum attacker. Paste your addresses and find out which is which — before it matters.
One distinction decides everything
A quantum computer running Shor's algorithm could derive a private key from a public key — but not from a public key hash. ShorWatch checks, for every address, whether the key or only its hash is on-chain.
Paste your addresses
Any mainnet address type — legacy, SegWit, Taproot. The scan runs in your browser against public block-explorer data. Nothing is uploaded, nothing is stored.
We check key exposure
Address reuse reveals your public key forever. Taproot publishes it by design. Never-spent hash addresses keep it hidden. Each address gets classified accordingly.
Get a clear verdict
Exposed or protected, in plain language, with the exact reason and what to do about it — including how BIP-360 quantum-resistant addresses fit in once they activate.
Free to check. Pro to stay safe.
The quantum threat isn't a one-off scare — it's a slow-moving migration that will take years. Pro keeps watch so you don't have to.
- Up to 5 addresses per scan
- Full exposure verdict & reasons
- Actionable recommendations
- Whole-wallet scan (xpub)
- Monitoring & alerts
- Whole-wallet scan from your xpub, ypub or zpub — every address derived in your own browser, the key never leaves your device
- Movement alerts — instant notice the moment funds leave a watched address. Alerts fire on detection; they can't block a transaction
- Exposure monitoring — know if any of your addresses becomes quantum-exposed
- BIP-360 migration alerts — know when quantum-resistant addresses go live, with a step-by-step playbook
- Exportable PDF report
- API access — audit entire UTXO sets programmatically
- Quantum-readiness reports for compliance & clients
- Post-quantum migration consulting
The risk model, honestly explained
Why is address reuse the biggest problem?
Legacy and SegWit addresses (starting with 1, 3 or bc1q) only publish a hash of your public key when they receive funds. The key itself stays hidden — until the first time you spend from that address, when the full public key is revealed in the transaction signature.
If you spend from an address and then keep receiving funds on it, those funds sit behind a public key that anyone can read from the chain. A future quantum attacker could target them at leisure — a so-called long-range attack.
Why are Taproot addresses flagged as exposed?
Taproot outputs (addresses starting with bc1p) place the public key directly on-chain by design — that's what makes them efficient. It also means every Taproot UTXO is theoretically harvestable by a future quantum computer, even if the address was never spent from.
This is not a bug and not an immediate threat — no quantum computer today comes remotely close. But for long-term cold storage measured in decades, it is a real design trade-off worth knowing about.
Coins on never-spent addresses — fully safe?
They are protected against long-range attacks, since only a hash is public. A residual short-range risk remains: the moment you broadcast a spend, your key becomes public for the minutes until the transaction confirms. That attack requires a quantum computer fast enough to work within one block interval — a far higher bar.
Is Bitcoin doing anything about this?
Yes. BIP-360 (February 2026) proposes a quantum-resistant address type, and BIP-361 (April 2026) sketches a phased retirement of vulnerable signatures. Migration will take years once activated. The practical playbook today: avoid address reuse, prefer hash-based addresses for long-term storage, and be ready to migrate when quantum-resistant addresses go live — ShorWatch Pro will tell you the moment that happens.
What this scanner does not know
It reads public per-address statistics, so it can't see inside multisig setups, inspect P2PK outputs from the 2009–2011 era, or know how your keys are managed. Treat results as an informed first pass, not an audit.
Do you store my addresses?
No. There is no server, no database, no analytics, no cookies. The page queries the public mempool.space API directly from your browser — the same data anyone can look up about any address.