In recent days, the usage of cloud computing in wireless networks offers more advantages to the users by storing resources with less complexity and ease to control. Data security is considered a critical aspect in a cloud computing environment due to the sensitive and confidential information of users stored in IOT. So, this paper introduces a Lightweight and Privacy-Preserving Two-Factor Authentication (TFA) with S-box based Flipping Module (SBFM) to provide data security for a user. The proposed scheme uses Unclonable Function Key (UFK) to provide a better solution for highly-secured cloud computing. Moreover, Reconfigurable Unpredictable Response Value (RURV) helps to generate the different response values for every clock cycle in IoT. Finally, Spartan 6 Field Programmable Gate Array (FPGA) performances of the proposed TFA-RURV-IoT are compared to existing TFA-URV-IoT protocols, whereas the simulation results show that proposed TFA-RURV-IoT achieves better results in terms of LUT, slices and flip flops.