“…The attacks discussed in the previous section have posed serious challenges for the PUF designers and manufacturers. To tackle this issue, various countermeasures have been introduced in the literature, including controlled PUFs [60,93], re-configurable PUFs [60], PUFs with noise-induced CRPs [94,91,87], to name a few. "Controlled PUFs" is the umbrella term given to PUFs, where the adversary does have a restricted access to the CRPs through either obfuscating the challenges/responses [26,28] or mechanisms used to feed the challenges/collect the responses [60,93,50,92,43,50,14].…”