A Passkey Based Recovery Mechanism for Blockchain Hardware Wallets

Blockchain hardware wallets have higher security assurances. Compared to software wallets, they offer an important differentiating security property called unicity. Unicity ensures the uniqueness of the seed/private key and ties ownership to a unique hardware entity, both physically and logically. This is highly desirable if high-value assets are involved in a transaction. However, this unicity property is lost as soon as a backup of the hardware wallet is created, even for future recovery purposes. In this paper, we propose a novel passkey based recovery mechanism that allows full recovery of user funds without the need for a backup of the seed in the hardware wallet, thus preserving its unicity and other security assurances. We demonstrate its practicality through a testbed, its superior security, and performance compared to others.