# Improving IoT Data Security and Integrity Using Lightweight Blockchain Dynamic Table
## 3 Blockchain Technology  
Blockchain technology has been predicted by the industry and research community as a technology with future applications that can play a key role in the management and control of IoT devices as well as adding security features [20]. This section describes the basics that have been used in designing the proposed solution and integrating Blockchain technology into it and how blockchain is a technology that enables viable security solutions to today's challenging IoT security problems. First, the section provides a brief explanation of blockchain, then identifies open-research IoT security problems and challenges that blockchain may provide solutions to. The department also scans blockchain-based solution literature for IoT security problems. As shown in Figure 1, a blockchain is essentially a decentralized, distributed, and shared database ledger with the inability to alter the transactions and records in it over a peer-to-peer (P2P) network [21]. After the data blocks are temporally sealed, they are restricted and validated by miners. By using Elliptical Curve Cryptography (ECC) and SHA-256 hashing, Blockchain provides strong encryption for data authentication and integrity [7]. The block data, as shown in Figure 2, contain a list of all transactions and a hash to the previous block. Having a complete record of all transactions in the blockchain makes it provide global trust distributed across borders. No matter how trusted third parties (TTP) or central authorities and services are, they can be disrupted, hacked, or malfunctioned. Misuse may also occur in the future. Figure 1: Blockchain architecture. In the blockchain, every transaction in a shared public ledger is verified by the consensus of the majority of mining nodes that actively participate in the validation and verification of transactions. In the Bitcoin network [22], miners validate the block by calculating a hash with leading zeros to achieve the difficulty goal. Block data become immutable once transactions are validated and verified by consensus, which makes erasing or changing the data an impossible task. A Blockchain can be built as follows: (1) a licensed (or private) network that can be restricted to a specific group of participants (this is called a public blockchain) or (2) without permission or a public network that is open to anyone to join. Permission blockchains provide more privacy and improve access control and this is called the Local Blockchain. Blockchain Platform in IoTThere are a variety of blockchain development platforms, such as Ethereum and Hyperledger, each with its own set of features [23]. [PERSON] created the Ethereum blockchain platform [24]. The most significant distinction between Ethereum and Bitcoin is a smart contract, which enables Ethereum to deploy applications on the blockchain [25]. Ethereum can do a variety of tasks, such as playing games, according to various smart contracts. As a result, Ethereum is also known as \"blockchain 2.0\". Ethereum has paved the way for a new generation of blockchain developers. Ethereum extends the remaining qualities of blockchain to mainstream apps, which are referred to as \"Decentralized Applications\" [26]. Ethereum is a relatively new platform among a range of platforms, with a high level of reliability and appeal. Hyperledger, on the other hand, is a Linux Foundation-supported blockchain interoperability application. It has a variety of platforms, including IBM's Fabric [27]. To accomplish privacy protection, the system takes into account the enterprise's structure and creates alternative protocols depending on different network topologies, such as \"Byzantine Fault Tolerance (BFT).\" Because it is more private, it is most commonly used in the financial business, which is concerned about personal privacy. IOTA is a blockchain platform developed by [PERSON]'s team [28]. It is mainly used on the Internet of Things, providing payment and file storage functions.