How to secure your private keys? (Self-custody)

Hardware Wallet Selection Criteria

1. Devices must support open-source firmware to allow independent verification of security claims.

2. Physical isolation between private key generation and external interfaces prevents remote extraction.

3. Tamper-evident casing ensures any physical intrusion attempt leaves visible traces.

4. Support for multisignature configurations adds redundancy against single-point failure.

5. Compatibility with major blockchain networks avoids reliance on third-party bridging tools.

Offline Key Generation Process

1. Air-gapped computers running verified Linux distributions eliminate network-based attack vectors.

2. Entropy sources must be manually collected using dice rolls or atmospheric noise generators.

3. BIP-39 mnemonic phrases are written on stainless steel backups, not paper or digital files.

4. Each word in the seed phrase is verified against the official BIP-39 word list before final storage.

5. No portion of the seed phrase is ever entered into an internet-connected device during setup.

Physical Storage Protocols

1. Steel backups are stored in geographically separate fireproof safes with humidity control.

2. Engraved metal plates avoid ink degradation, laser etching, or thermal fading over decades.

3. Access logs track who handled each backup and when, using handwritten ledgers only.

4. No biometric systems or cloud-synced notes are used to reference location or access details.

5. Private keys never coexist with recovery phrases in the same physical container.

Transaction Signing Workflow

1. Unsigned transactions are prepared on a separate air-gapped machine using deterministic inputs.

2. QR codes carrying transaction data are scanned by the hardware wallet without exposing private keys.

3. Manual confirmation of recipient address, amount, and fee is required on the device’s screen before signing.

4. Signed transactions are exported via QR code or USB and broadcast from an online node under strict firewall rules.

5. No software wallet ever holds a decrypted private key—even momentarily—during this flow.

Recovery Testing Procedures

1. Full restoration of funds is performed annually using only the physical backup and a fresh hardware device.

2. Test transactions are sent to newly generated addresses to verify signature validity on-chain.

3. Recovery timing is measured to ensure no delay exceeds acceptable thresholds for emergency access.

4. All test outputs are discarded immediately after confirmation; no testnet balances are retained.

5. Failure scenarios—including partial seed loss or corrupted firmware—are simulated and documented.

Frequently Asked Questions

Q: Can I use a smartphone camera to scan QR codes for transaction signing?Yes—if the phone runs a minimal OS with no background apps, camera permissions restricted to the wallet app only, and all network interfaces disabled during scanning.

Q: Is it safe to store private keys on a USB drive encrypted with VeraCrypt?No—USB drives lack secure element protection, and encryption keys may be extracted via cold boot or firmware-level attacks.

Q: Do hardware wallets protect against supply chain tampering?Only if purchased directly from verified vendors with batch-verified firmware hashes and unopened anti-tamper seals intact upon receipt.

Q: What happens if my hardware wallet’s screen malfunctions during signing?The device continues to function internally; users rely on tactile buttons and LED indicators to confirm actions, and signed outputs remain valid regardless of display status.