Air-Gapped Computers: Ultimate Security for Key Management

An air-gapped computer has never been and will never be connected to the internet. It's the highest security level for operations that must never be exposed to remote attacks.

What to Air-Gap

PGP private key operations (signing, decrypting). Cryptocurrency transaction signing for large holdings. Seed phrase generation and backup. Sensitive document creation. Password database master operations. Any operation where private key exposure would be catastrophic.

Setup

Use an old laptop with WiFi card physically removed. Install Tails or a minimal Linux distribution from a verified USB. Disable all wireless hardware in BIOS. Remove Bluetooth module if present. Never connect Ethernet. Transfer data only via USB drives or QR codes. Boot from read-only media when possible.

Data Transfer Protocol

For cryptocurrency: create unsigned transaction on the online computer, transfer to air-gapped via USB or QR code, sign on air-gapped, transfer signed transaction back, broadcast from online computer. For PGP: export public key to USB for distribution, import messages to decrypt on air-gapped, export encrypted responses via USB.