A 100-Bit-Output Modeling Attack-Resistant SPN Strong PUF with Uniform and High-Randomness Response

Strong physically unclonable function (Strong PUF) [1] is a unified solution for lightweight IoT edge device authentication (Fig. 1). Although recent research made breakthroughs on the conventional issue of modeling attack vulnerability, these studies had to limit the output to 1 bit [2] -[4] or 5 bits [5] using XOR in the final stage. To generate enough response bits for one authentication period, e.g., 100 bits, either 100-time server communications (latency/energy/CRP consumption in communications) or multiple parallel Strong PUF macros (huge area) are required. The reason of limitation is that the pre-XOR response bits have high correlation, and each bit is not random enough when the challenge input changes. In this case, an attacker can simplify the attack model and break the Strong PUF. It is a big challenge to expand the output space securely without increasing entropy sources.