# A Lightweight Blockchain-Based IoT Identity Management Approach
## 2 Related Work  
With the fast growth of the Internet of Things area, the role of identity management is expanding to cover sensors, actuators, and smart devices. The role is more about to grant access to IoT services and applications and to monitor sensors. Many scholars have undertaken the identity management of things area and proposed several models and frameworks in order to support the fast-growing IoT network. [PERSON] [9] proposed a framework for authentication and integrity protection while using simple cryptography operation. The work discussed the tamperproof authentication and the trust model, while taking the lightweight IoT units into consideration. [PERSON] et al. [10] presented a novel asymmetric mutual identity authentication scheme for IoT-based on hash algorithms and elliptic curve cryptography technique. The structure focuses on two primary roles, the platform and a terminal node, while a certificate authority center is responsible for issuing and verifying all of the exchanged certificates. [PERSON] et al. [11] tailored a novel holistic and privacy-preserving solution for the Internet of Things. They coped the authentication and access control systems with the claims-based approach. They also used the Idemix credential system to hide sensitive identity attributes. The works that are mentioned above lack implementation and real-world use cases; besides, all of the papers adopted the traditional IdM centralized approach that has already shown weak security and privacy performance. Moreover, combining cryptography primitives with the existing solutions without taking into consideration that the IoT decentralized network architecture and requirements, such as guaranteeing secure communication between different IoT entities, assuring data privacy and integrity, and providing high availability when authenticating and authorizing IoT entities, will lead to a standstill. On the contrary to the centralized approach, [PERSON] et al. [12] reviewed many works regarding identity management models while using blockchain technology. According to their review, few articles proposed particular identity models to manage things, while most of the studies used PKI (Public Key Infrastructure) mechanism for implementation. They also claimed that all of the reviewed identity models that are based on blockchain are not mature enough to back the IoT network. [PERSON] et al. [13] investigated a case of using blockchain in a smart home where they considered high resource devices as miners, responsible for handling all intelligent home communication and preserving the private blockchain. The work audited the security, integrity, and availability of the framework. Moreover, [PERSON] et al. [14] proposed a selective disclosure credentials scheme framework in order to ensure confidentiality, authenticity, and availability. Mainly, the work tries to fill the privacy research gap by enabling selective disclosure credentials while using the cryptography primitives that are offered by Ethereum blockchain and chainspace protocol. [PERSON] et al. [15] presented IoTchain; a three-tier blockchain-based IoT security architecture comprises an authentication, blockchain, and application layers that are designed to leverage many features, such as identity authentication, access control, and privacy protection. [PERSON] et al. [16] discussed the benefits of adopting the distributed ledger technology to advance the electronic healthcare domain. In this work, they discussed the need for using DLT in order to ensure the authenticity, integrity of the data generated from health, and wearable, embedded devices using IOTA protocol as a core technology of their work. To the best of our knowledge, all of the reviewed blockchain-based identity management solutions and decentralized identity frameworks did not discuss the identity management functions and lifecycle of an entity inside the network, the interoperability, or entities' interaction in the network.