Computer Standards & Interfaces 82 (2022) 103622 Available online 10 January 2022 0920-5489/© 2022 Elsevier B.V. All rights reserved. MFO-RPL: A secure RPL-based routing protocol utilizing moth-fame optimizer for the IoT applications Ali Seyfollahi , Meysam Moodi , Ali Ghaffari * Department of Computer Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran A R T I C L E INFO Keywords: Routing security RPL Rank attack Moth-fame optimization algorithm ABSTRACT The intricate features and autonomous confguration of Routing Protocol for Low-power and Lossy Networks (RPL) make it challenging to provide a key management solution and deploy it on constrained resources sensing systems. So far, various types of attacks, such as rank attacks, have been identifed on this protocol, so it is necessary to take appropriate countermeasures to mitigate and isolate their effects. This paper proposes the Moth-Flame Optimization-based secure scheme for RPL (MFO-RPL) to optimize the routing process and rank attack detection in RPL. MFO-RPL uses the petal algorithm to select the next-hop nodes and form the optimal path between the source and root in the graph. Then, rank attacks in RPL are detected using the Moth-Flame algorithm to prevent malicious nodes from being selected as the preferred parent. Simulation fndings under different scenarios revealed that MFO-RPL has fewer lost packets, rank switching, convergence time, and attacks than comparative schemes. 1. Introduction Around 30 billion smart things such as smartphones, dust-driven sensors, wearables, and cyber-physical systems from all over the world are connected via the Internet and are growing exponentially [1,2]. Different communication standards are adapted for these heterogeneous networks and pervasive communications such as Low-power and Lossy Networks (LLN) [3] and IPv6 over Low-powered Wireless Personal Area Networks (6LoWPAN) [4–7]. These things have constrained processing, energy resource and storage, low data rate, and bandwidth [8,9]. In LLN, numerous embedded devices send massive volumes of data to the Internet [10], with the inherent challenges of low Packet Delivery Ratio (PDR) and high packet losses [11]. The Internet Engineering Task Force (IETF) has introduced the RPL routing protocol [12] to meet the various requirements of applications and obligations [13]. Network designers can utilize RPL’s unparalleled fexibility by using the different metrics they want for the RPL Objective Function (OF). Given each network’s dynamic topology and potential vulnerabil- ities, data routing and addressing consider two crucial concerns in IoT networks that require appropriate attention [14]. Based on the layered architecture, IoT enables Internet communication between physical devices of heterogeneous networks [15]. Layers in the IoT ecosystem’s architecture meet each other’s needs, and their interaction also affects the whole system’s performance [16]. Small size, low hardware, and communication capabilities have led to limitations in the functions of aggregation, transmission, and communication between nodes and their routing in the IoT [17]. Routing of messages exchanged between nodes is one of the main challenges in IoT communications, which is very important due to the need to maintain the uniformity of the path packets between the source and destination [18] and has led to various pro- posals for routing in the IoT. 1.1. Motivation Considering IoT environments’ dynamics, discovering security challenges, and providing automated solutions require more time and energy [19]. In IoT, network security is critical, especially when packets pass through heterogeneous networks of billions of intelligent nodes [20] to reach a server on the Internet. The scale and rate of new attacks on sensor devices in the IoT are increasing day by day, and therefore the study of data transmission security requires a lot of attention [21]. In the meantime, creating secure routing is challenging. This essential need to secure the routing process between multiple IoT devices across hetero- geneous networks requires extensive research. One of the signifcant information security concerns in IoT is network layer security. RPL can be vulnerable to common routing attacks in wireless * Corresponding author. E-mail address: a.ghaffari@iaut.ac.ir (A. Ghaffari). Contents lists available at ScienceDirect Computer Standards & Interfaces journal homepage: www.elsevier.com/locate/csi https://doi.org/10.1016/j.csi.2022.103622 Received 15 December 2020; Received in revised form 2 October 2021; Accepted 4 January 2022