I. Introduction
As the exchange of personal information among Internet of Things (IoT) devices increases, the security of encryption keys has become necessary [1]. Since conventional encryption techniques using random number generators and nonvolatile memory (NVM) entail serious encryption leakage risks [2], the physically unclonable function (PUF) has been developed to enable a higher level of security and cost-effectiveness [3]. As the PUF is a hardware-based encryption technique that does not share resources for processing encryption keys, the encryption keys generated from the PUF can be secured more safely than software-based encryption techniques that share the resources in public. In addition, the PUF is a promising security solution for IoT devices where hardware resources are constrained due to its lightweight characteristics [4], [5].