An air-gapped computer is physically isolated from any network. It’s the most secure way to manage crypto keys.
What Air-Gapped Means
| Connected | Air-Gapped |
|---|
| Connected to the internet | Never connected to any network |
| Vulnerable to remote attacks | Immune to remote attacks |
| Can be hacked via network | Must be physically accessed |
| Software updates automatic | Manual updates via USB |
Air-Gapped Setup Options
| Option | Cost | Security |
|---|
| Dedicated laptop (offline) | £200-500 | High |
| Raspberry Pi (offline) | £50-100 | High |
| Old smartphone (never online) | £0-100 | Moderate |
| Hardware wallet (Ledger, Trezor) | £50-200 | Very high (similar concept) |
How to Set Up an Air-Gapped Computer
| Step | Action |
|---|
| 1 | Get a dedicated device (laptop, Raspberry Pi) |
| 2 | Install a clean OS (Linux Mint or Ubuntu) |
| 3 | Never connect it to the internet (not even once) |
| 4 | Install crypto software via USB |
| 5 | Generate keys and sign transactions offline |
| 6 | Transfer signed transactions via USB to online device |
Software to Install Offline
| Software | Purpose |
|---|
| Electrum (Bitcoin) | Cold storage wallet |
| Sparrow Wallet | Advanced Bitcoin wallet |
| Tails OS | Privacy-focused OS (boots from USB) |
| Linux Mint | Clean OS for the device |
Download the software on a different computer and transfer via USB.
Signing Transactions Offline
| Step | Action |
|---|
| 1 | Create unsigned transaction on online device |
| 2 | Transfer to air-gapped computer via USB |
| 3 | Review and sign on air-gapped computer |
| 4 | Copy signed transaction back to USB |
| 5 | Broadcast from online device |
Air-Gapped vs Hardware Wallet
| Factor | Air-Gapped PC | Hardware Wallet |
|---|
| Cost | £50-500 | £50-200 |
| Setup complexity | High | Low |
| Ease of use | Low | High |
| Security | Very high | Very high |
| Portability | Low | High |
| Firmware verification | Manual | Built-in |
For most users, a hardware wallet (Ledger/Trezor) provides equivalent security with much better usability.
Advantages of Air-Gapped
| Advantage | Why |
|---|
| No firmware supply chain risk | You control the software |
| Full transparency | Open source, fully auditable |
| No USB vulnerability (if using QR) | QR codes for transaction transfer |
| Customisable | You decide the software stack |
Disadvantages
| Disadvantage | Why |
|---|
| Complex setup | Not for beginners |
| Manual updates | Each update needs USB transfer |
| USB risk | USB could carry malware between devices |
| Physical security | Entire device must be physically secured |
Bottom Line
An air-gapped computer provides maximum security by never connecting to the internet. Use a dedicated device with Linux, install crypto software via USB, and sign transactions offline. For most people, a hardware wallet is a better balance of security and usability. Air-gapped setups are for advanced users with large holdings or specific security requirements. Never connect the air-gapped device to any network — not even once.
This content is for educational purposes only. Not financial advice. Do your own research before investing.