# Improving IoT Data Security and Integrity Using Lightweight Blockchain Dynamic Table
###### Abstract  
Over the past few years, the Internet of Things (IoT) is one of the most significant technologies ever used, as everything is connected to the Internet. Integrating IoT technologies with the cloud improves the performance, activity, and innovation of such a system. However, one of the major problems which cannot be ignored in such integration is the security of the data that are transferred between the client (IoT) and the server (cloud). Solving that problem leads to the use the of IoT technologies in more critical applications and fields. This paper proposes a new security framework by combining blockchain technology with the AES algorithm. Blockchain technology is used and modified to protect data integrity and generate unique device identification within minimal power consumption and best performance. The AES algorithm is used to improve the data confidentiality when being transmitted to the server. The outcomes demonstrated that the proposed solution improves the security system of the IoT healthcare data and proved its efficiency and power consumption compared to other methods.  
IoT; security; AES encryption; blockchain; private blockchain; dynamic table +
Footnote †: journal: Applied  
In recent years, blockchain technology has been designed as a high-security solution for many security-needs applications, including the IoT. Blockchain technology has been predicted by the business and scientific communities to be a disruptive technology that will have a significant impact on how IoT devices are managed, controlled, and most crucially, secured [8]. Furthermore, blockchain technology has attracted a lot of attention as it moves toward decentralized designs and addresses security, anonymity, traceability, and centralization. Using blockchain, entities and techniques are enforcing security and privacy attributes in various IoT security levels [9]. IoT systems may be built with a suitably distributed consensus-based architecture and security challenges resolved by integrating blockchain technology. Even if this is the perfect match, it is still a difficult task. The majority of current blockchain technologies are not compatible with the IoT environment and cannot satisfy its unique requirements. Because IoT settings are resource-constrained, computationally intensive, power-intensive, and storage-constrained, blockchain has a high computational complexity, a small amount of scalability, a large bandwidth overhead, and a high latency. Some devices are not recommended to be used with IoT [10]. Therefore, recent solutions have been trying to adopt the blockchain technology by modifying and optimizing the blockchain generating and managing techniques [11; 12; 13]. This paper has presented a new mechanism to improve the security and efficiency of IoT networks using a new blockchain mechanism.  
Our suggested system makes the following contributions:  
* We offer a multi-layer blockchain-based method for safeguarding the privacy and security of IoT devices while also increasing system scalability.
* Multiple-hashcode-based access control is utilized to provide safe communication with multiple organizations without Trusting Third Parties (TTP);
* We assess our approach by executing a prototype implementation to match the IoT criteria.  
The findings reveal that our system is more effective and efficient in terms of transaction latency and throughput; we also conduct a security analysis of the suggested solution in comparison to other recent research in the literature.