This purpose of this study is to implement a firmware and simulation testbench program to incorporate message security and checksum verification using a lightweight cryptographic scheme on resource-constrained hardware. The designed program is stored in the ROM as part of the firmware. The sensor controller, which communicates with the master microcontroller, selects the instructions from the ROM, performs computation, and transfers data using the data bus. The program utilizes Keccak as a keyed permutation to encrypt and decrypt messages with the session key (KS). Additionally, a brief literature review on post-quantum cryptography and side-channel analysis is presented.