Air-Gapped Multi-Chain Hardware Wallet

A secure, air-gapped hardware wallet for the XDC Network supporting multiple wallets across multiple blockchains. Every signature is produced offline: transactions cross the air gap as QR codes, private keys live inside an ATECC608A secure element, and accounts are exported using UR:CRYPTO-HDKEY encoding.

A hardware wallet has to keep private keys secret even if the host computer is fully compromised, while still being usable across several blockchains. That means no key material can ever touch an online machine, signing must happen on a constrained device, and the whole flow has to stay simple enough for real users.

Air-gapped, secure-element signing

• Private keys are generated and stored inside an ATECC608A secure element; ECDSA signing happens on-device and keys never leave it.
• The wallet is fully air-gapped: unsigned transactions come in as QR codes, signatures go back out as QR codes — no USB, no network path to the keys.
• Accounts are exported with UR:CRYPTO-HDKEY encoding for clean interop.
• A single device supports multiple wallets across multiple chains on the XDC Network.

• A working multi-chain, air-gapped hardware wallet for the XDC Network
• Secure-element-backed key management with offline QR signing

Add to confirm: supported chains/coins, signing latency, and the host platform (Raspberry Pi model).