At present, clients can outsource lots of complex and abundant computation, e.g., Internet of things (IoT), tasks to clouds by the “pay as you go” model. Outsourcing computation can save costs for clients and fully utilize the existing cloud infrastructures. However, it is hard for clients to trust the clouds even if blockchain is used as the trusted platform. In this article, we utilize the verification method as [email protected] by only two rational clouds, who hope to maximize their utilities. Utilities are defined as the incomes of clouds when they provide computation results to clients. More specifically, one client outsources two jobs to two clouds and each job contains
tasks, which include
identical sentinels. Two clouds can either honestly compute each task or collude on the identical sentinel tasks by agreeing on random values. If the results of identical sentinels are identical, then client regards the jobs as correctly computed without verification. Obviously, rational clouds have incentives to deviate by collusion and provide identical random results for a higher income. We discuss how to prevent collusion by using deposits, e.g., bit-coins. Furthermore, utilities for each cloud can be automatically assigned by a smart contract. We prove that, given proper parameters, two rational clouds will honestly send correct results to the client without collusion.
Intellectual contracts based on blockchain technology improve the efficiency of supply management of an automobile enterprise by optimizing the transactional costs of supply logistics. The present research featured KAMAZ PTC. The goal was to develop an interaction mechanism for all participants of an intellectual contract in supply activities. The article includes a review of Russian and foreign publications about intellectual contracts in various business spheres, supply management efficiency, optimization of transactional costs, and blockchain technology. The study made it possible to build an interaction mechanism of the parties involved in a blockchain intellectual contract. It also revealed a pattern of changes introduced to the intellectual contract at different stages of interaction between the initiator and suppliers. The authors also highlighted the difference between smart contract and intellectual contract. An intellectual contract appears as a logical development of a smart contract and allows the sides to change the terms. The party interaction mechanism can improve the supply efficiency as it optimizes the magnitude of transactional costs.
AbstractCentral management of electronic medical systems faces a major challenge because it requires trust in a single entity that cannot effectively protect files from unauthorized access or attacks. This challenge makes it difficult to provide some services in central electronic medical systems, such as file search and verification, although they are needed. This gap motivated us to develop a system based on blockchain that has several characteristics: decentralization, security, anonymity, immutability, and tamper-proof. The proposed system provides several services: storage, verification, and search. The system consists of a smart contract that connects to a decentralized user application through which users can transact with the system. In addition, the system uses an interplanetary file system (IPFS) and cloud computing to store patients’ data and files. Experimental results and system security analysis show that the system performs search and verification tasks securely and quickly through the network.
Traditional centralized access control faces data security and privacy problems. The core server is the main target to attack. Single point of failure risk and load bottleneck are difficult to solve effectively. And the third-party data center cannot protect data owners. Traditional distributed access control faces the problem of how to effectively solve the scalability and diversified requirements of IoT (Internet of Things) applications. SCAC (Smart Contract-based Access Control) is based on ABAC (Attributes Based Access Control) and RBAC (Role Based Access Control). It can be applied to various types of nodes in different application scenarios that attributes are used as basic decision elements and authorized by role. The research objective is to combine the efficiency of service orchestration in edge computing with the security of consensus mechanism in blockchain, making full use of smart contract programmability to explore fine grained access control mode on the basis of traditional access control paradigm. By designing SSH-based interface for edge computing and blockchain access, SCAC parameters can be found and set to adjust ACLs (Access Control List) and their policies. The blockchain-edge computing combination is powerful in causing significant transformations across several industries, paving the way for new business models and novel decentralized applications. The rationality on typical process behavior of management services and data access control be verified through CPN (Color Petri Net) tools 4.0, and then data statistics on fine grained access control, decentralized scalability, and lightweight deployment can be obtained by instance running in this study. The results show that authorization takes into account both security and efficiency with the “blockchain-edge computing” combination.
With the recent rise in the cost of transactions on blockchain platforms, there is a need to explore other service models that may provide a more predictable cost to customers and end-users. We discuss the Contract Service Provider (CSP) model as a counterpart of the successful Internet Service Provider (ISP) model. Similar to the ISP business model based on peered routing-networks, the CSP business model is based on multiple CSP entities forming a CSP Community or group offering a contract service for specific types of virtual assets. We discuss the contract domain construct which encapsulates well-defined smart contract primitives, policies and contract-ledger. We offer a number of design principles borrowed from the design principles of the Internet architecture.
Because of its unique decentralization, encryption, reliability, and tamper-proof, the block chain system makes smart contracts break through the shackles of the lack of trusted environment, and its application field keeps expanding. We read the source code and official documents of Bitcoin, Ethereum, and Hyperledger to explore the operation principle and implementation mode of smart contract. By analyzing the evolution process of smart contracts in blockchain and the sequence of its function expansion, according to the multirole business process of supply chain, we design a semipublic smart contract chain model based on Ethereum and Hyperledger in order to provide useful inspiration and help for the future research of smart contracts in blockchain applied in supply chain.