A spin-orbit torque-based key generation system with key concealment and attack detection through irreversible physical changes.

The confidentiality of key storage devices determines the trustworthiness of cryptographic systems. Existing attack detection methods typically depend on monitoring external variations of devices, which can be circumvented by attackers. This work presents a unified key generation and protection scheme using spin-orbit torque (SOT) devices. By unifying static and dynamic entropy sources within the same devices, the key generation system functions both as physically unclonable functions and as true random number generators. In idle states, devices retain only random numbers and conceal any extractable key. Illegal key access irreversibly destroys stored random numbers, offering a robust attack detection mechanism. A comparator circuit flags illegal key extraction activity, ensuring that the user can promptly detect and revoke compromised keys. This approach merges key generation, concealment, and detection into a single physical platform, providing a hardware-rooted, unforgeable method for key protection.