International Journal of Electrical and Computer Engineering (IJECE) Vol. 12, No. 2, April 2022, pp. 2139~2146 ISSN: 2088-8708, DOI: 10.11591/ijece.v12i2.pp2139-2146  2139 Journal homepage: http://ijece.iaescore.com A dynamic data encryption method based on addressing the data importance on the internet of things Dana Khwailleh, Firas Al-balas Department of Computer Science, Jordan University of Science and Technology, Ar-Ramtha, Jordan Article Info ABSTRACT Article history: Received May 24, 2021 Revised Sep 19, 2021 Accepted Oct 10, 2021 The rapid growth of internet of things (IoT) in multiple areas brings research challenges closely linked to the nature of IoT technology. Therefore, there has been a need to secure the collected data from IoT sensors in an efficient and dynamic way taking into consideration the nature of collected data due to its importance. So, in this paper, a dynamic algorithm has been developed to distinguish the importance of data collected and apply the suitable security approach for each type of data collected. This was done by using hybrid system that combines block cipher and stream cipher systems. After data classification using machine learning classifiers the less important data are encrypted using stream cipher (SC) that use rivest cipher 4 algorithm, and more important data encrypted using block cipher (BC) that use advanced encryption standard algorithm. By applying a performance evaluation using simulation, the proposed method guarantees that it encrypts the data with less central processing unit (CPU) time with improvement in the security over the data by using the proposed hybrid system. Keywords: Block cipher Security over internet of things Stream cipher This is an open access article under the CC BY-SA license. Corresponding Author: Firas Albalas Department of Computer Science, Jordan University of Science and Technology Ar Ramtha 3030, Ar-Ramtha, Jordan Email: faalbalas@just.edu.jo 1. INTRODUCTION The internet of things (IoT) is defined as connecting all objects in different environments through the internet. These objects collect different data, and sometimes data may be of high importance, whether it is about the surrounding environment or the user itself [1]. Therefore, it is necessary to ensure that only the receiver can safely recover this information [2] and to protect this information from any risk that may occur to it, such as penetration by unauthorized persons or eavesdropping by a third party [3]. Figure 1 shows the definition of IoT. To get the widespread of internet IoT obtained that by enabling easy access and collaboration with a large number of devices, for example, personal appliances, control cameras, sensors, motors, and screens, the IoT will promote development through application, in order to massively use risks, and attack information provided by these creatures to provide new services to citizens, companies, and public administrations [4]. Today, there are many uses of the internet such as making data globally available to authorized users and online data processing units. Of course, the data can be sensitive and this violates the privacy of users. This risk is exacerbated by the trend to separate the sensor network infrastructure and applications. Therefore, a security solution must be provided to achieve an appropriate level of security for the IoT [5]. Due to the lower cost and the time of marketing, IoT manufacturers did not give the security issue a priority to be part of their IoT devices. Few manufactured devices include a software-based security programs like firmware, however, the previous solutions do not take into consideration the different usage patterns of IoT