Watch-only and cold wallet
Ownbit's cold storage uses two phones. One is taken permanently offline and holds your private key — the cold wallet. The other stays online but holds public keys only — the watch-only wallet. They exchange nothing but plaintext QR codes.
How the two phones divide the work
| Cold wallet (offline) | Watch-only wallet (online) | |
|---|---|---|
| Holds | Private key / seed | Public keys and addresses only |
| Network | Permanently offline (SIM out, Wi-Fi cleared) | Online — everyday phone is fine |
| Can it sign? | Yes — this is the only place signing happens | No |
| Can it spend alone? | No network to broadcast | No key to sign |
| Shows balances? | No | Yes — monitors funds and builds transactions |
The watch-only wallet prepares a transaction and shows it as a QR code; the cold wallet scans it, signs offline, and shows the signature as a QR code; the watch-only wallet scans that back and broadcasts it. The private key never crosses the gap.
Why hold public keys only online?
A watch-only wallet can see everything an observer could already see on the public blockchain — addresses and balances — but it physically cannot move funds, because it has no private key. That means the internet-connected device, the one actually exposed to remote attacks, is never the device that can sign. Compromising it leaks no ability to spend.
When should I use this instead of a hot wallet?
A hot wallet keeps the key on your everyday phone and is fine for smaller, frequently used balances. The two-phone cold setup adds real friction — every send needs two QR scans — so it pays off for higher-value holdings you touch rarely. Many people run both: a hot wallet for spending money and a cold wallet for savings.
Frequently asked questions
Do I need two phones?
Yes, for the cold-wallet setup: one permanently offline signer and one online watch-only wallet. The offline phone can be an inexpensive spare — it never needs a SIM or network.
Can the watch-only wallet steal my funds if my online phone is hacked?
No. The watch-only wallet holds public keys only and cannot sign or spend. An attacker who compromises the online phone still cannot move funds without the offline signer.
Does the cold phone ever need internet?
No — it stays permanently offline. It only needs power and a camera to scan QR codes. To update the app you temporarily reinstall while online, then go offline and re-import the mnemonic.
Last updated:
Download Ownbit
Install the app, then set up a cold wallet or MultiSig for the workflow you need.