Machine Learning Resistant Amorphous Silicon Physically Unclonable Functions (PUFs)

Many crypto protocols rely heavily on the security of keys that are stored in device memory and are susceptible to malware attacks. Physically unclonable functions (PUFs) have been proposed as an alternative [1] whose response to external stimuli (challenge) is determined by their microscopic structure, which is difficult to clone. PUF operation consists of two phases: enrollment and deployment. During the enrollment process, the manufacturer creates a challenge response pair (CRP) library by probing the device with unique binary challenges and measuring/generating the corresponding digitized response. The CRP data set is then stored for the deployment phase where the PUF device can be authenticated by probing it with a subset of challenges in the CRP data set and comparing the responses. To be a strong security primitive a PUF must exhibit behavior that is i) deterministic, ii) unpredictable, and iii) unique.