The New Advanced Society

Both academia and industry have conducted several researches to arrive at a conclusion that Distributed Ledger and Blockchain technology can potentially play a crucial role to manage, control and secure all networked device. Schematic diagram of Blockchain empowered IoT Cloud is depicted at Figure 3.3. Accordingly, this can be seen as a promising security solution to counter the challenges with IoT related security issues. Some vital features of blockchain which are useful for IoT in general and IoT security specifically are described below.

For Addressing: Typically, Blockchain uses 160 bit address. As a standardized cryptographic function in Blockchain, it is capable to address 20 bytes or a 160 bit hash of the public key which is the output of Elliptic Curve Digital Signature Algorithm (ECDSA). Hence it is found to be a better addressing means than IP V6 (128 bit) for provisioning of Global Unique Identifier (GUI) at the time of allocating and assigning address for an IoT device.

Figure 3.3 Blockchain empowered IoT Cloud.

For Authentication: Smart contracts can be deployed with Blockchain to provide authentication using decentralized means. This can also be used to provide authentication to smart devices connected to the IoT system. Inherent advantages of Blockchain can also be suitably utilized for effective authentication establishment.

For Authorization: Using Smart contracts deployed over Blockchain and also integrating multiple smart contracts, effective authorization and access control mechanism for connected IoT devices can be established. This mechanism is found to be faster and efficient compared to commonly used protocols like Oath, Open ID, etc.

For Privacy: Smart contracts are such versatile tools, whereby using this over Blockchain enables ensuring data privacy. This technique can control access by enforcing a designated set of conditions and time to allow or deny access to users or group of users to control the acquired data or even transit data for the IoT system. Smart contracts can also be programmed to decide on patch updation. Using this means, changing of ownership and provisioning of IoT devices are found to be smooth exercises.

For Data Integrity: In a Blockchain based arrangement, the connected IoT devices are cryptographically safeguarded and signed by a verified and legitimate sender who is holding a unique public key and GUID. Secure storage mechanism along with its event time stamping of the distributed ledger facilitates data integrity for the interconnected IoT devices. For example, to maintain data integrity in a distributed system TrustChain is proposed with an aim to perform trusted transactions using blockchain.

For Identity of Things: Blockchain technology can be used to identify IoT devices with a set of attributes. Attribute management for the connected smart devices of IoT system holds a key factor for the Identity and Access Management (IAM). Attributes in terms of deployment location coordinates as registered by GPS, make, model and device serial no of IoT device along with its ownership, change or renovation of ownership play a crucial role with respect to identity of things.

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.