PUF-FSM: A Controlled Strong PUF

This paper presents the PUF finite state machine (PUF-FSM) that is served as a practical {\it controlled} strong PUF. Previous controlled PUF designs have the difficulties of stabilizing the noisy PUF responses where the error correction logic is required. In addition, the computed helper data to assist error correcting, however, leaks information, which poses the controlled PUF under the threatens of fault attacks or reliability-based attacks. The PUF-FSM eschews the error correction logic and the computation, storage and loading of the helper data on-chip by only employing error-free responses judiciously determined on demand in the absence of an Arbiter PUF with a large CRP space. In addition, the access to the PUF-FSM is controlled by the trusted entity. Control in means of i) restricting challenges presented to the PUF and ii) further preventing repeated response evaluations to gain unreliability side-channel information are foundations of defensing the most powerful modeling attacks. The PUF-FSM goes beyond authentications/identifications to such as key generations and advanced cryptographic applications built upon a shared key.