Blockchain Platforms Overview for Industrial Iot Purposes
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______________________________________________________PROCEEDING OF THE 22ND CONFERENCE OF FRUCT ASSOCIATION Blockchain Platforms Overview for Industrial IoT Purposes Nikolay Teslya, Igor Ryabchikov SPIIRAS St.Petersburg, Russia [email protected], [email protected] Abstract—There are a lot of blockchain platform there is an active development of blockchain technology, which implementationsavailable today. To be integrated into the smart provides a simpler solution for the problems presented above. space for Industrial IoT the blockchain platform should support not only token exchange butalsosmart contract distribution and The blockchain is a distributed transaction ledger supported launching, fault toleranceconsensus mechanism andequivalence by a set of nodes that does not have a single point of trust and between participants to create and implement new blocks and failure. Each node performs the validation of the added contracts. The paper provides analysis of the most used consensus transactions, and the consensus mechanism allows the mechanisms, specific features of public (permissionless) and arrangement of nodes in the transaction order. In other words, private (permissioned) blockchains. Also a description of blockchain technology allows the creation of a common blockchain platforms that satisfy the requirements for the IIoT information space of many independent participants with platformdevelopment is provided.By the result of the analysis the generally accepted rules for its modification (including platform and specific modules have been selected for modification rights) in which the participants do not trust each implementation of blockchain for industrial IoT platform. other in complete manner. Abstracting, blockchain can be perceived as a trusted platform for the execution of programs, I. INTRODUCTION providing certain guarantees of reliability and consistency. These guarantees depend on the specific implementation. The organization of interaction between the smart factory The operation principles of the blockchain technology can be components both internally and with other factories is one of the summarized as follows. Participants in the blockchain network main issues for Industry 4.0 concept. Until now, there are a lot share the common information space (state) and the modification of solutions based on the using of the IoT concept, which allows rules (program code). In a number of implementations of the uniting many components into a single information space and technology, there are also persist built-in mechanisms for the providing information exchange between them. Regarding to the distribution of new software code, called smart contracts. Each industry such union can be based on the concept of Industrial participant (in accordance with the accepted rights) can make a Internet of Things (IIoT), which is the use of IoT for the call to the shared program code to modify the state. The call is interaction of physical, virtual and social industrial components made through the creation of transactions. The participant in a single information space also known as smart space. notifies the others about the transaction that he would like to However, production becomes more and more decentralized and make. Transactions of all participants for a certain period of time several problems appear, among which the following can be are collected in blocks for the purpose of bundling and reducing highlighted: the need to provide interoperability between the overhead costs associated with reaching a consensus. After components in the smart space and between smart spaces; trust that, in accordance with the implemented mechanism of between the participants of the information space; control over consensus, the parties agree on the next received transaction the distribution of resources (such as maintenance time, energy, block. Each new block contains a hash of the previous block, etc.) and finished products [1]. thereby forming a linked list. By sequentially executing all To provide the interoperability between the smart space transactions starting from the first block, the current state can be components, the ontology and ontology matching mechanism restored. The consensus mechanism for the most of blockchain can be used. Such approach is already widely described and used technology implementations, makes it possible to realize the so- in the number of projects, e.g. [2], [3]. The solution of the trust called coherence in the long run, ensuring that in case of the problem between components is more complicated due to absence of changes after some time from the last update all heterogeneity of the participants. It can be solved with the help participants will share the common state. In accordance with the of digital signature [4] and access control [5] mechanisms that implementation of the mechanism for achieving consensus, the needs central partner that can provide trust and access control for difference between the states of a pair of nodes may be delay (the all the components of IIoT. Control over resources distribution node has not yet had time to receive and apply a new transaction and finished products can be carried out using a database block) or a temporary branch (two different valid blocks of accessible to all components. These solutions are quite complex transactions were received by different nodes). and require the deployment of complex infrastructure to provide The aim of the paper is to analyze available blockchain fault tolerance, performance and availability. At the same time, solutions in order to be implemented for Industry 4.0 case. The ISSN 2305-7254 ______________________________________________________PROCEEDING OF THE 22ND CONFERENCE OF FRUCT ASSOCIATION main questions to be analyzed are implemented consensus x Proof-of-work (PoW) [7]; algorithm, publicity of network, smart contract support, platform x Proot-of-elapsed-time (PoET)) [8]; to be used for providing all these functions in IIoT platform. x Proof-of-stake (PoS) [9]; These parameters are partly depending on each other, for x Byzantine Fault Tolerance (BFT) [10]; example, the consensus mechanism is depending on the x Federated Byzantine Agreement (FBA) [11]; publicity of the network. To be appropriable for IIoT platform x Various combinations of the above algorithms. [1] blockchain should support smart contracts, support block generation without mining procedure and consensus mechanism A. Proof-of-work that can work with a low number of users. The Proof-of-work mechanism provides the ability to create The rest of the paper is structured as follows. Section 2 transaction blocks by any participant also known as miners provides information about papers that studies blockchain randomly at approximately equal intervals. The participant who implementations. Section 3 provides descriptions of consensus will create the next block is not determined in advance. After mechanisms. Section 4 describes permissonless and creating a valid block, the participant distributes it to the permissioned implementations of blockchain network and their network, the rest participants should accept it, validate and advantages and disadvantages. Section 5 provides some proceed to create the next block. But a situation is possible in blockchain platforms and modules that can be used for which several valid blocks will be created (by different integration of blockchain and IIoT. participants). This situation is viewed as a conflict that will be resolved by selecting a longest chain that is defined by consensus II. STATE OF THE ART of more than 51% of participants. Since only one chain can be At the moment there are many implementations of the active, unaccepted block is added to the block tree and marked blockchain technology. Publication search showed the existence as orphaned. This makes it possible to implement an attack, in of at least 20 platforms. Their main differences are the which an attacker tries to convince a participant that a certain implementation of the consensus mechanism, the transactions transaction has been made (for example, a payment for services), validation mechanism (and, consequently, the guarantees of perform the desired actions (get a service), and then cancel the reliability and consistency) and functionality (for example, transaction by creating a new valid block, thereby receiving the support only currency exchange or blockchain for common service and having returned payment. With Proof-of-work, the purposes with the ability to create smart contracts). In the case probability of generating a valid transaction block is of a common-purpose blockchain (with the support of smart proportional to the computational power that the participant has contracts), there are differences in available state storage (for the generation it is necessary to solve the complex structures, as well as opportunities to limit the performance of mathematical problem). So the miner or group of miners should smart contracts. control more than 50% of computational power of whole network to successfully implement this type of attack. 7KDW¶s As blockchain technology has gained popularity not so long why it DOVRFDOOHG³DWWDFN´. For large blockchain networks ago, many of the proposed projects are at an early stage, so they with a large number of participants and a uniform distribution of do not have qualitative documentation describing the algorithms computing power, the probability of this attack is small due to that support the claimed guarantees and therefore are not