Security Solution
Emerging technologies like IoT as well as Bockchain has presented many technological advantages. Subsequently advantages of integrating Blockchain and IoT have been studied and analyzed by many researchers. The primary aspect of IoT device level security is mainly expected to cover diversified factors like managing huge amount of data, privacy preservation of user, trust assurance, confidentiality and also integrity. It also merits its significance related to advantages associated with Blockchain and distributed ledger applications. In this subsection we will consider some of the prominent research contributions addressing security concerns of IoT using Distributed Ledger technology with Blockchain.
A Blockchain Connected Gateway has been proposed in [13] for maintaining security and adaptive users’ privacy, where the authors have made use of Bluetooth Low Energy empowered IoT devices. Crucial data of user are protected from being accessed without user’s consent by means of the Gateway. To implement authentication and also secrecy in terms of privacy preservation, a digital signature scheme is also proposed. As basic fundamental architecture of the system, blockchain networks are applied to address privacy related issues between application providers of IoT and their users by encrypting users’ applied choices and keeping them for further reference in the network.
Authors have highlighted in [14] regarding difficulty for the mobile and handheld devices for performing required computation for proof of work for reaching a consensus due to their resource limitations. Hence a concept of edge computing was introduced wherein such mobile devices are facilitated to use the resources present at the level of edge devices for computations in order to get the proof of work.
A blockchain based data storage scheme was proposed in [15] for protecting and storing huge volume of generated data by IoT devices. This secured method applied register and forward methodology. The devices located at the edge actually collect data from the IoT devices. Then this data is registered and associated with the particular IoT device in the blockchain and subsequently forwarded to a Distributed Hash Table (DHT). Blockchain based cryptographic means are used to address queries on specific data. It is registered as a transaction in the blockchain for verification of authentication. After being successfully authenticated, DHT then releases the desired data. In this approach blockchain works like a trusted third party (TTP) for storing of data and its management, provides protection to the stored data and also facilitates user authentication.
A distributed cloud architecture was proposed in [16] using blockchain utilizing Software Defined Networking (SDN) enabled controller fog nodes as edge nodes in the system. The edge nodes process data analysis, their classification for the huge volume of acquired data from the IoT devices present at the edge of the network. This system also took care of efficient data traffic management of the system using data distribution within the fog and associated edge nodes.
To improve scalability and also for eliminating the role of a TTP, in Manzoor et al. [17] have presented a blockchain based proxy controlled re-encryption scheme [18]. This is implemented with deployment of Smart Contracts. In this scheme the proxy re-encryption facilitates data transparency and mapping between the data owner and the registered user associated to the Smart Contract. In this, secure storage and sharing of the IoT acquired data’s confidentiality is maintained by first performing data encryption before their storage on cloud and then subsequently re- encrypting the stored data before their sharing among users.
In Kim et al. [19] have suggested an idea based on Blockchain of Things (BoT) model to address the corresponding hacking issues of IoT devices. A specialized method called color spectrum chain blockchain technique is used. This proposal tried to address the security vulnerabilities in the sensors. In this technique Thin Plate Spline (TPS) is used along with multiple-agreement algorithm to access required security strengths of the system.
A fingerprint verification based automatic door locking system was proposed and implemented using mobile handsets in [20] based on blockchain technology. This system implementation has been proved to be efficient about the prevention of attempt to forge, any move to tamper or leak biometric information of the users. In the system the users could authenticate themselves using a mobile handset with biometric fingerprint printing authentication coupled with blockchain based security measures.
3.5.3 Proposed Distributed Ledger-Based IoT Cloud IAM
Distributed Ledger implementation needs a basic platform namely a Blockchain. As the blockchain facilitates distributed database and essential characteristics of immutability, Distributed Ledger implementation can be done upon this platform efficiently. Blockchain as a technology can easily be integrated with access control and data sharing mechanisms. This way it may provide a new means for elimination of shortcomings of the age old traditional schemes. Blockchain provides solutions to many problems that are more effective to provide data integrity, fairness, authenticity, security, and distribution [21]. By virtue of the inherent cryptographic properties and decentralized storage and processing, as a technology Blockchain has been assessed as a suitable method for providing IAM services for IoT ecosystem as deliberated by the authors of [22, 23].
In any cryptographically secured system key management plays a vital role. In our proposed method Elliptic Curve Digital Signature Algorithm (ECDSA) may be conveniently used for generating public and private keys for the devices and the IoT clusters associated with Blockchain nodes. It provides the same level of security as with the RSA method. We have selected this approach depending upon a detailed comparison between encryption algorithms described by [24]. The ECDSA based program needs comparatively reduced power consumption from other similar methods. Hence it also suits the requirements of IoT infrastructure, keeping the constraint resources availability of the IoT devices.
Figure 3.4 above represents a schematic diagram of the proposed Blockchain based IoT Cloud model for the IAM service implementation. Vital aspects of the proposed model are as follows.
1 (i) Establishment of an Ethereum-based private blockchain as a core of the distributed ledger network.
2 (ii) Device address and user Ids are mapped over the nodes of the blockchain.
3 (iii) Storage of the acquired data from the devices is done off the blockchain inn the cloud storage.
4 (iv) Use of multiple smart contracts for ensuring ‘user’ and ‘things’ mapping for effective service management as well as identity management.
5 (v) Use of blockchain consensus mechanism for verification of data access as a registered event logged in the blockchain
6 (vi) Use of cloud nodes for processing and relieving the edge devices from loading of processing due to their constrained resources availability.
7 (vii) Superimposing the IAM functionality of Cloud with the inherent advantages of blockchain related information security and event logging.
Figure 3.4 Proposed model of blockchain-based IoT Cloud for IAM.
3.6 Conclusion
Steadily the use of IoT devices is making ingress to our day to day lives affecting improvements towards our living conditions. It is quite evident to note that IoT is one of most prominent and emerging technologies in today’s scenario. The proliferation and application of IoT in all spheres of life is ever increasing for ease of life as well as efficient functioning of things.
