The Internet of Things (IoT) is currently a main focus of research across disciplines. In a household IoT environment, almost all devices are connected to the internet. In the case of a smart city, most of the city homes and departments are managed through the network. One small security vulnerability is enough to take down an entire city or parts of it. Hence communications should be encrypted. Physical Unclonable Functions are commonly used for this purpose. A PUF key is not stored anywhere thus providing the advantage of secrecy. In the current paper, two designs of a reconfigurable PUF are proposed, a speed optimized reconfigurable hybrid oscillator arbiter PUF and its power optimized counterpart. Both designs can be introduced into two different categories of IoT devices, one where high performance is needed and one with low power consumption. The Hamming distance of the speed optimized and power optimized designs is 47 % and 48 % with power consumption of 167.5 μW and 143.3 μW, respectively.