Research Article Renovated XTEA Encoder Architecture-Based Lightweight Mutual Authentication Protocol for RFID and Green Wireless Sensor Network Applications Manikandan Nagarajan , 1 Muthaiah Rajappa , 1 Yuvaraja Teekaraman , 2 Ramya Kuppusamy , 3 and Amruth Ramesh Thelkar 4 1 School of Computing, SASTRA Deemed University, 613 401, Thanjavur, India 2 Department of Electronic and Electrical Engineering, The University of Sheffield, Sheffield, S1 3JD, UK 3 Department of Electrical and Electronics Engineering, Sri Sairam College of Engineering, 562 106, Bangalore City, India 4 Faculty of Electrical & Computer Engineering, Jimma Institute of Technology, Jimma University, Ethiopia Correspondence should be addressed to Yuvaraja Teekaraman; yuvarajastr@ieee.org and Amruth Ramesh Thelkar; amruth.rt@gmail.com Received 10 January 2022; Revised 7 February 2022; Accepted 19 February 2022; Published 10 March 2022 Academic Editor: Rashid A Saeed Copyright © 2022 Manikandan Nagarajan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Wireless sensor networks find applications everywhere in day to day activities right from attendance entry systems to healthcare monitoring systems. The evolution of the Internet of Things (IoT) as the Internet of Everything (IoET) makes the wireless sensor network omnipresent and increases the use of Radio Frequency Identification (RFID) for the proper identification of devices and sensor nodes which are mostly battery operated. As technology evolves, security threats also increase rapidly. This mandates a strong and energy-efficient green solution. This work attempted to address these issues by effectively deploying the lightweight encryption scheme called Extended Tiny Encryption Algorithm (XTEA). Though the XTEA is lightweight and famous, it is commonly known for various attacks. Our work patches the security threats in the XTEA by applying domain-specific customization, random number utilization, and undisclosed key renewal techniques. Two custom Renovated XTEA Mutual Authentication Protocol (RXMAP) encoder architectures, namely, RXMAP-1 and RXMAP-2, are proposed based on the replacement of accurate computational blocks with approximate blocks. The proposed RXMAP protocol is evaluated for its computational and storage overhead and verified against various security threats using BAN logic formal verification and informal verification. The proposed encoder architectures are simulated for functional verification, and ASIC implementation is done with a 132 nm process node. ASIC implementation results show that the proposed designs RXMAP-1 and RXMAP-2 occupy 53.11% and 53.31% lesser area compared to XTEA I and 52.97% and 53.18% lesser area compared to XTEA II implementation. The total power consumed by the proposed encoder architectures RXMAP-1 and RXMAP-2 is 68.76% and 71.64% lesser than XTEA II implementation, respectively, while maintaining the equal throughput. 1. Introduction Advancement in technology facilitates people to enjoy wire- less devices with smart sensors. Wireless sensor networks (WSN) are finding applications in various places, viz, health monitoring, IoT (Internet of Things), logistics, and ware- houses [1]. As the application areas are getting wider, the privacy and security issues are also getting complex. So, securing information exchanged in the networks is the need of the hour. There are many algorithms available in the liter- ature for securing the communication among the sensors and systems. Most of the secured algorithms are complex and computation intensive in nature [2]. Wireless sensor networks are composed of Radio Frequency Identification (RFID) tags and low power-consuming sensors [3]. Deploy- ing complex security algorithms is not a feasible solution for Hindawi Wireless Communications and Mobile Computing Volume 2022, Article ID 8876096, 12 pages https://doi.org/10.1155/2022/8876096