Design and Implementation a Strong CRO-PUF with Maximum Reliability to Securely Generate Cryptographic Keys in IoT Applications

With the expansion and spread of the Internet of Things, the ineffectiveness of the old encryption methods was proven. PUF was introduced as a hardware solution and is currently the best choice for securing IoT devices. The PUF structure based on the ring oscillator (RO-PUF) is one of the most well-known and desirable PUFs. It is also the best structure for the implementation of FPGA. Compared to other schemes, the responses generated by RO-PUF are the most reliable. This paper introduces an RO-PUF that provides maximum reliability, has a vast challenge-response pair (CRP) space, and is resistant to modeling attacks. A new comparator block is added to the CRO-PUF structure to evaluate the response bits and, when the value difference of the two counters is significant enough, to determine the stable response bits at the output. The proposed structure was implemented on the Xilinx FPGA board. The experiment shows that the proposed structure has ideal reliability, uniqueness, and uniformity close to the ideal value. This structure is resistant to modeling attacks due to its reconfigurability. Due to its maximum reliability and CRP, this structure can be the best choice for lightweight cryptographic applications.