Since in IoT systems the devices are mostly connected among them, the data exchange is a vital activity in the network. In this kind of networks, not only non-sensitive data exchange is performed, but also sensitive data (digital signatures, login credentials, account numbers, personal images, and so on) are shared. Therefore, new appropriate approaches to encrypt the secret information are highly required.
Ad Hoc networks are considered essential elements of the Internet of Things (IoT). An ad hoc network is a self-organizing network architecture, a peer-to-peer network, where each node is capable of data collect- ing, storage, processing, and forwarding. This type of networks connects various kinds of devices or things, e.g., sensors, actuators, RFID tags, smartphones, which are very different in terms of size, capability, and functionality. The typical scenario is the Internet of Things (IoT) where the ad hoc networks have been extensively used in different fields of engineering, especially in environment monitoring, intelligent transportation, smart cities, etc.
This research presents an experimental setup of a fractional-chaos based-cryptosystem for ad hoc networks under the IEEE 802.15.4 standard. The proposed cryptosystem is composed of a novel chaotic pairing approach between the coordinator node and end-devices nodes to sending data into the network. More specifically, the RF-data of the IEEE 802.15.4 frame is encrypted using a fractional-order encryption key and four iterative steps. It is worth to note that the chaotic key is based on a fractional-order chaotic system, which is derived from the fractional calculus theory. Next, the experimental validation of the cryptosystem is shown sending an encrypted image between ARM digital platforms and wireless Xbee modules.
As well known, a generic IoT system can be adequately represented and described by using three main layers: perception, transportation, and application. According to the existent security issues against the IoT at different layers, specific constraints and security requirements have been defined. Then, a security approach should provide confidentiality, integrity, authentication, authorization, and freshness.
On the other hand, the cryptographic strength of symmetric ciphers (block, stream, involution, lightweight) in terms of security is defined by the key length. The number of rounds for a specific cipher is determined by the original cipher designers, stating the optimum number of rounds for optimum security. More rounds and longer key length trans- late to a safer system. Nevertheless, as for the performance of the system, it is mainly measured by the number of rounds that a cipher has to be executed. More rounds are equal to more computation overhead. Therefore, when designing a system, the balance between security, cost, and performance has to be accounted for the IoT environment.
Therefore, the data encryption of the ad hoc networks needs to be tackled through unconventional security approaches such as generating secret random keys locally.
For details consult:
Montero-Canela, R., Zambrano-Serrano, E., Tamariz-Flores, E. I., Muñoz-Pacheco, J. M., & Torrealba-Meléndez, R. (2020). Fractional chaos based-cryptosystem for generating encryption keys in Ad Hoc networks. Ad Hoc Networks,97, 102005.