An energy efficient encryption technique for the Internet of Things sensor nodes

Securing data at the back end in Internet of Things (IoT) applications, such as a cloud server, is easy due to the ample computational resources at that stage. However, securing the data at the device level before outsourcing to the central server is necessary, considering the attack scenarios at the interface between the device and the back-end machine. The end devices, resource-constrained in terms of power consumption, memory, processing capabilities, and area, cannot use conventional security solutions to thwart attacks and breaches. This work proposes an encryption algorithm based on the Advanced Encryption Standard for resource-constrained IoT sensor nodes by reducing the algorithm's computational complexity for higher-bit key streams. The encryption technique employs energy optimization techniques to reduce energy consumption while encrypting the data. The paper explores the coordinate functions intrinsic to the AES round function. It proves that the coordinate functions within the AES round function achieve equivalence through an affine transformation of the input. The consequences of the complexity reduction regarding cryptanalytic attacks and the justification based on mathematical analysis are discussed. The work carried through this research aims at building the security level down to the low-power sensor nodes primarily used in IoT application scenarios wherein the proposed resource-efficient encryption technique can be used to provide security services before sending the data to back-end machines. The suggested encryption technique was evaluated experimentally on the Zolertia Firefly and RE-motes utilising the Contiki operating system. The proposed algorithm shows efficiency in throughput, memory, and energy consumption compared to the standard AES implementation.