# Improving IoT Data Security and Integrity Using Lightweight Blockchain Dynamic Table
## 4 Literature Review  
According to [36], there are many security threats in IoT, which are categorized into two main threads: physical and logical threats. The proposed solution in this proposal is mainly focused on the logical threats; therefore, the literature review focuses on the logical threats of IoT devices, which contain security leaks and threads when storing and transmitting data from IoT devices to base stations in the cloud. In 2016, [PERSON] et al. [37] defined a new blockchain framework for controlling the access of IoT. The first contribution of the framework consists of providing a reference model for the proposed solution in terms of objectives, models, and mechanisms of the IoT architecture. The second is the FairAccess for the fully decentralized pseudonymous and privacy-preserving characteristics. This contribution also gave a framework for authorization management. The authors indicated that the new FairAccess blockchain technique used different types of transactions, which is different from one that is used in bitcoin, which provides get, delegate, and revoke access. The framework had been tested and examined with a Raspberry PI device for a local blockchain. The main limitation of the proposed solution is the performance of the framework when used with a real-time IoT monitoring application. In 2017, [PERSON], [PERSON] and [PERSON]. [38] worked on preventing stored secret key learning when using AES encryption by proposing a false key-based AES encryption technique. To hide the intermediate data during the reconstructing stage, Wave Dynamic Different Logic (WDDL) with an XOR gate has been utilized. The main objective of the proposed solution was to protect the data against Chosen Plaintext Attack (CPA) attack. However, the solution has not been tested against other AES attacks, such as brute force attacks and random key chaining (RCK). [PERSON] et al. [39] also presented a blockchain-based technique for upgrading IoT device firmware by including various manufacturers and antivirus businesses into the blockchain system and obtaining firmware files from the system. Before it can be synchronized by other blockchain nodes in the system, it must be confirmed by the antivirus company node, and then IoT devices must request the files from the blockchain node. This design has been sent to an antivirus firm for verification. Because the number of verification nodes is so small, the verification node bears a significant strain. Furthermore, the attacker only needs to target a few nodes to do systemic damage. In 2018, [PERSON] and [PERSON] [40] studied the ability to use blockchain technology to enhance the IoT ecosystem security. They determine the main field of using blockchain to improve the security and privacy of IoT. The blockchain can be used and act as a catalyst by enhancing the security and reliability of IoT, as it works as a Machine-to-Machine (M2M) interaction mechanism. The study shows that it can track billions of devices connected to IoT systems by deploying blockchain technology. Furthermore, they explain how the threats to IoT security can be detected using the Shodan search engine, which they describe as \"the world's first search engine for Internet-connected devices\". Instead of a detailed explanation of how blockchain technology can be used to improve IoT security systems, they did not offer a clear mechanism of how to implement blockchain in the IoT. Furthermore, they did not show the impact of using blockchain on IoT performance. In 2019, [PERSON] et al. [41] proposed a lightweight security system using a chaotic system and AES encryption. They combine logistic and Lorenz chaotic systems to create a 5-D chaos system, which is used to generate the key of AES encryption. The AES that was used in the proposed solution had been modified by reducing the processing complexity, which results in improving the performance by 145%.