## 5 Discussion and Future Challenges
### Challenges of Integrating Blockchain and IoT  
With the incorporation of blockchain technology, there are a few security concerns that should be noted. One of the main obstacles for businesses and developers is the dissimilarity in the technologies' underlying functioning principle and architecture (Figure 8). Thus, it is essential to first identify the problems that could raise during the integration of these two technologies. _Size of the Blockchain:_ Blockchain usually has vastly different operational and static data sizes. For example, Bitcoin and Ethereum have grown to be between 250 GB and 1 TB in size, respectively, making them prohibitively large in comparison to IoT systems. Due to the limitation of computation resources and storage of current IoT devices, it is challenging to integrate blockchain with IoT. Given its large file size, the widespread implementation of blockchain in IoT infrastructure is limited. One possible solutions is to move the data to cloud storage. However, cloud computing usually has a centralized structure, whereas blockchain is decentralized, which might lead to framework conflicts. _Required Computing Power:_ Blockchain employs PoW and consensus algorithms to provide high-security features such as immutability, robust authentication, etc., consuming large amounts of computational resources and energy to execute these algorithms. However, IoT devices employ lightweight protocols and processes that require little in the way of power. Blockchain and IoT systems use two different protocols, and they could not be more dissimilar in terms of the amount of computing power and energy required. Making them work together is a difficult undertaking in and of itself. _Security:_ Integrating blockchain technology with IoT systems has been hailed by several experts as a means of ensuring the safety of connected devices. However, the data dependability of IoT devices becomes a major challenge as a result of this integration. A typical blockchain only ensures the integrity of data in the absence of attacks. The failure of hardware, the use of counterfeit hardware, the use of compromised networks and hardware, etc., are all potential causes of data corruption in the IoT. Thus, it is important and challenging to design security algorithms for the incorporation of blockchain into IoT infrastructure. _Challenges of Identity Management:_ The management of one's own identity is essential. Weak data correlation, insufficient data, and outdated or erroneous data are just some of the information collection issues related to identification records. Items such as automobiles, houses, paintings, and digital publications all benefit from possession management for the purposes of copyright management, property rights management, and traceability. The blockchain can be used to record ownership in a way that is immutable. The blockchain method ensures effective contract execution and the subsequent tracking of property ownership. The blockchain method verifies ownership claims and establishes the existence, validity, and uniqueness of choices by using hashing algorithms and timestamps to provide immutable digital evidence such as video, text, and audio. Proper ownership must be confirmed when it has been established. _Users' Anonymity and Data Privacy:_ The potential application of blockchain technology has been proposed as a viable remedy to tackle concerns surrounding data confidentiality due to its intrinsic attributes of immutability, verifiability, and decentralized structure. However, due to the limited capacity of the IoT, it might not be practical to run all the privacy preservation algorithms to ensure the privacy of the data on an IoT-supported blockchain. Thus, eliminating this complexity opens the door to attacks and compels us to make security concessions. Furthermore, while the immutability of data is improved by the fact that all blocks in a blockchain contain identical information, this also raises privacy concerns for users.