Beyond Cold Storage: Why Hardware Wallets Need Open Source and Clear Signing

The article reviews major crypto thefts (Bybit, Feb 2025; Radiant, Oct 2024) where attackers compromised developer machines and injected malicious signing code so hardware wallets blindly signed transactions, resulting in large-scale ETH theft. It argues that offline key storage alone is insufficient and recommends open-source firmware, inspectable hardware, reproducible builds and on-device transaction decoding (clear signing) to allow users and auditors to verify intent; it presents Ambire Ice as an example design emphasizing on-device verification.