Abstract
A hardware life cycle controller gates each life cycle transition behind a bidirectional handshake. An external agent writes a 128-bit user nonce U, and the controller concatenates it with a 128-bit device nonce X drawn from the on-chip entropy source (ES) and with the monotonic transition counter CNT, forming a 288-bit challenge that neither party fixes alone. A KMAC engine then performs two passes over that challenge. The first pass derives a device proof Z1 = KMAC(Y1, U || X || CNT) from a shared secret Y1 and exposes Z1, along with X and CNT, in read-only registers, allowing the agent to authenticate the part when Y1 is device-unique. The second pass recomputes the expected user response Z2 = KMAC(Y2, Z1) from a second shared secret, and a hardware comparator checks it against the value the agent wrote back, advancing to one-time programmable memory programming only on a match. Because the controller increments the counter before requesting entropy, and because the counter value is included in the message, no two attempts ever share a challenge, so a recorded exchange cannot be replayed even when the entropy source is uncalibrated. Because the scheme uses only symmetric cryptography, it is amenable to lightweight root-of-trust hardware implementations.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Osorio, Miguel and Schaffner, Michael, "Hardware-Anchored Bidirectional Mutual Authentication with Combined Entropy for Secure Integrated Circuit Life Cycle Transitions", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/12347