PUF-FSM: A Controlled Strong PUF

Physical unclonable functions (PUF), as hardware security primitives, exploit manufacturing randomness to extract instance-specific challenge (input) response (output) pairs (CRPs). Since its emergence, the community started pursuing a strong PUF primitive that is with large CRP space and resilient to modeling building attacks. A practical realization of a strong PUF is still challenging to date. This paper presents the PUF finite state machine (PUF-FSM) that is served as a practical controlled strong PUF realization. Previous controlled PUF designs have the difficulties of stabilizing the noisy PUF responses where the error correction logic is required. In addition, the helper data computed to assist error correction eventually leaks information, which poses the controlled PUF under the threaten of fault attacks or reliability-based attacks. The PUF-FSM easily gets around this problem by only employing error-free responses judiciously determined on demand in the absence of an Arbiter PUF that has a large CRP space. In addition, the access to the PUF-FSM is controlled by the trusted entity. Control in means of restricting challenges presented to the PUF and 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 authentication and identification applications to such as key generations and advanced cryptographic applications built upon a shared key.