Keep your keys out of hackers’ reach.
In this article, we’ll explore what an Air-Gapped device is, how it works, and the advanced security technologies it uses to protect sensitive data from modern cyber threats.
What is an Air-Gapped Device?
The main goal of an Air-Gapped system is to stop all data movement in or out unless it is manually controlled, to protect sensitive information from hacking or leaks.
An Air-Gapped system is a computer without any network connections. But more than that, it is part of a complete security strategy designed to protect highly sensitive data. These systems are completely disconnected from all networks — including the internet, local area networks (LAN), and any wireless connections like Bluetooth or Wi-Fi.
The main goal of using Air-Gapped devices is to keep data absolutely safe, especially for systems that require maximum security. This is useful in fields like the military, banks, cryptos, government offices, or research groups.
In most Air-Gapped setups, data is moved in or out through a strictly controlled physical device. This is often a USB drive, MicroSD Card, or similar device. Additional methods include QR codes and manual input.
This combination of physical separation, manual control, and strict monitoring helps ensure the highest level of protection against cyberattacks and data leaks.
Air-Gapped cryptocurrency wallets
One of the most modern and increasingly popular uses of the air-gap strategy is with cold wallets. In the cryptocurrency world, ownership is defined by knowledge of private keys, so keeping that data secure is essential.
Here’s how they’re used:
Maximum security for Private Keys
Air-gapping your wallet means your keys are inaccessible to hackers, regardless of potential software security flaws. For this approach to be effective, the seed/key backup must not be stored online, even if encrypted. Remember, you can never be 100% sure your computer is safe, but hackers cannot steal what isn’t online or isn’t digital.
Offline transaction signing
Users can create a transaction request on an online device (like a computer or smartphone). This unsigned transaction is then transferred to the Air-Gapped device (via QR codes or SD cards).
The Air-Gapped device, which holds the private key, then signs the transaction. The signed transaction is then transferred back (via QR/SD card) to the online device to be broadcast and published to the blockchain. This process ensures the private key never touches an internet-connected device.
Protection against remote attacks
Because there’s no physical or wireless connection to any network, Air-Gapped devices are immune to remote cyberattacks, phishing scams, and network vulnerabilities that could compromise online wallets.
Ideal for large holdings and long-term storage
For individuals or institutions holding significant amounts of cryptocurrency or planning to hold it for the long term (often called “hodling”), Air-Gapped solutions provide the highest level of security, reducing the risk of theft or loss.
Air-Gapped & Multisig: Advanced security
Multisig (short for “multi-signature”) is a system that requires signatures from several keys for a crypto transaction to happen. Instead of just one private key to send money, multisig might need 2 out of 3, or 3 out of 5 devices (or people) to sign, depending on how it’s set up.
Combining multisig with Air-Gapped devices creates a much stronger layer of security. Each Air-Gapped device holds a different part of the signing system. All of them are separate from the internet, which completely stops the risk of remote attacks or private keys being stolen.
For example, in a 2-of-3 setup:
- Three Air-Gapped devices each hold a different private key.
- If any two of these devices sign a transaction, the transfer becomes valid.
- If one device is lost or broken, the user still controls their funds and doesn’t lose assets.
For organizations or groups managing assets (like DAOs or investment funds), the multisig Air-Gapped model allows for clear delegation of signing power and internal control. It also lowers the risk of inside threats or human error.
In short, combining Air-Gapped and multisig is a great solution for both individuals who want to protect large amounts of money and organizations that need a highly secure, flexible, and lasting security system.
The future of Air-gapped devices in Web3 and DeFi
Even though hot wallets are more convenient for DeFi interactions, air-gapped wallets remain crucial for long-term asset storage, secure transaction signing, and protection against cyberattacks. Many organizations and individuals use a tiered storage model, where air-gapped wallets act as the “last layer of security.”
Staking, voting, and multisig platforms have already started to support offline transaction signing. Users can create and sign transactions with an air-gapped device, then transfer the data using a USB or QR code to an online device for broadcasting. Some protocols even allow for delegated signing or multi-signature authentication from several devices.
Common Air-Gapped devices
Devices like the Blockstream Jade and Coldcard stand out in this category, as they can be operated entirely air-gapped – meaning they never need to connect directly to an internet-enabled device. This significantly reduces the attack surface compared to wallets like Ledger or Trezor, which require USB or Bluetooth connections and companion apps.
However, it’s worth noting that Coldcard and Jade are Bitcoin-only devices. If you require multi-asset support (e.g. Ethereum, USDT, or other altcoins), solutions like Trezor or Ledger remain necessary.
Conclusion
While Air-Gapped systems aren’t right for every situation, they play a key role in protecting sensitive data, industrial systems, and digital assets from internet risks. As attacks become more advanced, understanding and correctly using the Air-Gapped device is an important step to boost information security.
Need further guidance?
Our in-house Cybersecurity team at BitcoinVN offers 1:1 consulting sessions designed to help you take full control of your digital assets – securely and confidently.
Whether you’re just getting started with self-custody, exploring advanced setups like MuSig, or want to harden your operational security, our experts will guide you step-by-step toward true self-sovereignty. No fluff, no shortcuts – just practical, Bitcoin-native security tailored to your needs.
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