Cold Wallet

Cold wallet

Separate signing from connectivity by keeping keys offline while still making everyday verification and transfers practical.

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Cold WalletWatch WalletQR offline signing

Overview

Keep private material on an air-gapped device that never needs to touch the network.

Feature highlights

Mirror addresses on an online device to monitor balances and prepare transfers safely.

No extra hardware

Turn a spare phone into an air-gapped cold signer — nothing to buy.

Feature highlights

Use one device to stay offline and another to prepare transactions, monitor balances, and handle broadcasting.

Offline signer

Keep private material on an air-gapped device that never needs to touch the network.

Watch wallet pairing

Mirror addresses on an online device to monitor balances and prepare transfers safely.

Human-verifiable QR flow

Scan unsigned data in, sign offline, and scan the signature back to broadcast.

How it works

Transfer only QR-encoded transaction data between devices, so keys stay isolated throughout the signing process.

Prepare on a Watch Wallet

Mirror addresses on an online device to monitor balances and prepare transfers safely.

Sign on an offline device

Keep private material on an air-gapped device that never needs to touch the network.

Scan back and broadcast

Scan unsigned data in, sign offline, and scan the signature back to broadcast.

Security design

Why the Ownbit cold wallet is safe to trust

Five properties you can check, not promises.

Your own phrase, or one from the OS

Import any BIP39 phrase, passphrase included. A new one is standard BIP39, 12 or 24 words, with entropy straight from the OS — and no Math.random fallback, so a missing secure source fails the generation rather than weakening it.

Offline from first second to last

The signing phone never joins Wi-Fi, mobile data or Bluetooth. Nothing can leak over a network it never touches — everything crosses as a QR code.

Your own phone, not someone’s hardware

An ordinary Android phone or iPhone you already own. No vendor secure element, no custom firmware, no extra chip that could copy a phrase out.

Every QR code is readable

Ownbit’s own encoding and the published standards other wallets speak — both plaintext and documented, so any code can be decoded and checked before you approve it.

Since 2018, zero security incidents

In production since 2018, never a security incident. The design never relied on secrecy: keys offline, codes readable, standard cryptography.

Use the same cold wallet to sign for other wallets

On Android 5.x the cold wallet also speaks published QR standards, so wallets like Sparrow, MetaMask, Rabby and Solflare can use it as their offline signer. They see public keys and signatures; the keys stay on the offline phone.

Ownbit as an external signer Protocol reference

Download

Download Ownbit for the setup you need

Install the app, explore secure mode, set up MultiSig, or build a Cold Wallet flow for higher-value storage.

Download Ownbit View supported assets