Vertical Federated Learning Based on Consortium Blockchain for Data Sharing in Mobile Edge Computing

The data in Mobile Edge Computing(MEC)contains tremendousmarket value,and data sharing canmaximize the usefulness of the data.However,certain data is quite sensitive,and sharing it directly may violate privacy.Vertical Federated Learning(VFL)is a secure distributed machine learning framework that completes joint model training by passing encryptedmodel parameters rather than raw data,so there is no data privacy leakage during the training process.Therefore,the VFL can build a bridge between data demander and owner to realize data sharing while protecting data privacy.Typically,the VFL requires a third party for key distribution and decryption of training results.In this article,we employ the consortium blockchain instead of the traditional third party and design a VFL architecture based on the consortium blockchain for data sharing in MEC.More specifically,we propose a V-Raft consensus algorithm based on Verifiable Random Functions(VRFs),which is a variant of the Raft.The VRaft is able to elect leader quickly and stably to assist data demander and owner to complete data sharing by VFL.Moreover,we apply secret sharing todistribute the private key to avoid the situationwhere the training result cannot be decrypted if the leader crashes.Finally,we analyzed the performance of the V-Raft and carried out simulation experiments,and the results show that compared with Raft,the V-Raft has higher efficiency and better scalability.

Asymmetric Consortium Blockchain and Homomorphically Polynomial-Based PIR for Secured Smart Parking Systems

In crowded cities,searching for the availability of parking lots is a herculean task as it results in the wastage of drivers’time,increases air pollution,and traffic congestion.Smart parking systems facilitate the drivers to determine the information about the parking lot in real time and book them depending on the requirement.But the existing smart parking systems necessitate the drivers to reveal their sensitive information that includes their mobile number,personal identity,and desired destination.This disclosure of sensitive information makes the existing centralized smart parking systems more vulnerable to service providers’security breaches,single points of failure,and bottlenecks.In this paper,an Improved Asymmetric Consortium Blockchain and Homomorphically Computing Univariate Polynomial-based private information retrieval(IACB-HCUPPIR)scheme is proposed to ensure parking lots’availability with transparency security in a privacy-preserving smart parking system.In specific,an improved Asymmetric Consortium Blockchain is used for achieving secure transactions between different parties interacting in the smart parking environment.It further adopted the method of Homomorphically Computing Univariate Polynomial-based private information retrieval(HCUPPIR)scheme for preserving the location privacy of drivers.The results of IACB-HCUPPIR confirmed better results in terms of minimized computation and communication overload with throughput,latency,and response time with maximized drivers’privacy preservation.Moreover,the proposed fully homomorphic algorithm(FHE)was compared against partial-homomorphic encryption(PHE)and technique without encryption and found that the proposed model has quick communication in allocating the parking slots starting with 24.3 s,whereas PHE starts allocating from 24.7 s and the technique without encryption starts at 27.4 s.Thus,we ensure the proposed model performs well in allocating parking slots with less time and high security with privacy preservation.

Directed Acyclic Graph Blockchain for Secure Spectrum Sharing and Energy Trading in Power IoT

Peer-to-peer(P2P)spectrum sharing and energy trading are promising solutions to locally satisfy spectrum and energy demands in power Internet of Things(IoT).However,implementation of largescale P2P spectrum sharing and energy trading confronts security and privacy challenges.In this paper,we exploit consortium blockchain and Directed Acyclic Graph(DAG)to propose a new secure and distributed spectrum sharing and energy trading framework in power IoT,named spectrum-energy chain,where a set of local aggregators(LAGs)cooperatively confirm the identity of the power devices by utilizing consortium blockchain,so as to form a main chain.Then,the local power devices verify spectrum and energy micro-transactions simultaneously but asynchronously to form local spectrum tangle and local energy tangle,respectively.Moreover,an iterative double auction based micro transactions scheme is designed to solve the spectrum and energy pricing and the amount of shared spectrum and energy among power devices.Security analysis and numerical results illustrate that the developed spectrum-energy chain and the designed iterative double auction based microtransactions scheme are secure and efficient for spectrum sharing and energy trading in power IoT.

Cross-Domain Authentication Scheme Based on Blockchain and Consistent Hash Algorithm for System-Wide Information Management

System-wide information management(SWIM)is a complex distributed information transfer and sharing system for the next generation of Air Transportation System(ATS).In response to the growing volume of civil aviation air operations,users accessing different authentication domains in the SWIM system have problems with the validity,security,and privacy of SWIM-shared data.In order to solve these problems,this paper proposes a SWIM crossdomain authentication scheme based on a consistent hashing algorithm on consortium blockchain and designs a blockchain certificate format for SWIM cross-domain authentication.The scheme uses a consistent hash algorithm with virtual nodes in combination with a cluster of authentication centers in the SWIM consortium blockchain architecture to synchronize the user’s authentication mapping relationships between authentication domains.The virtual authentication nodes are mapped separately using different services provided by SWIM to guarantee the partitioning of the consistent hash ring on the consortium blockchain.According to the dynamic change of user’s authentication requests,the nodes of virtual service authentication can be added and deleted to realize the dynamic load balancing of cross-domain authentication of different services.Security analysis shows that this protocol can resist network attacks such as man-in-the-middle attacks,replay attacks,and Sybil attacks.Experiments show that this scheme can reduce the redundant authentication operations of identity information and solve the problems of traditional cross-domain authentication with single-point collapse,difficulty in expansion,and uneven load.At the same time,it has better security of information storage and can realize the cross-domain authentication requirements of SWIM users with low communication costs and system overhead.KEYWORDS System-wide information management(SWIM);consortium blockchain;consistent hash;cross-domain authentication;load balancing.

Task-Attribute-Based Access Control Scheme for IoT via Blockchain

As a new form of network,the Internet of things(IoT)is becoming more widely used in people’s lives.In this paper,related theoretical research and practical applications of the IoT are explored.The security of the IoT has become a hot research topic.Access controls are methods that control reasonable allocations of data and resources and ensure the security of the IoT.However,most access control systems do not dynamically assign users’rights.Additionally,with some access control systems,there is a risk of overstepping other user’s authority,and there may exist a central authority that is a single point of failure.Therefore,to solve these problems,this paper proposes a Task-Attribute-Based Access Control scheme for the IoT via blockchain that combines the access control technologies of both the IoT and blockchain.This model,which merges the advantages of task-based access controls and attribute-based access controls,is perfectly integrated with blockchain technology.This model uses hash functions and digital signature algorithms to ensure the authenticity and integrity of the data,and it can dynamically allocate users’minimum privileges and thus perfectly solves the single point of failure problem.The model is implemented using a Geth client and solidity code,and the simulation results demonstrate the effectiveness of the model.

A Review: Consensus Algorithms on Blockchain

Blockchain is a distributed public ledger that keeps track of all transactions that have ever taken place in the system. As a distributed ledger, a consensus mechanism is required to ensure all the transaction functions properly. In order to reach a consensus, it is critical to emphasize the importance of performance and efficiency. The use of the right consensus algorithm will significantly improve the efficiency of a blockchain application. This paper reviewed several types of consensus algorithms used in blockchain and discusses the idea of a new consensus algorithm that can improve the performance of consortium blockchain.

Secure Model of Medical Data Sharing for Complex Scenarios

In order to secure the massive heterogeneous medical data for the complex scenarios and improve the information sharing efficiency in healthcare system,a distributed medical data ledger model(DMDL)is proposed in this paper.This DMDL model has adopted the blockchain technology including the function decoupling,the distributed consensus,smart contract as well as multi-channel communication structure of consortium blockchain.The DMDL model not only has high adaptability,but also meets the requirements of the medical treatment processes which generally involve multientities,highly private information and secure transaction.The steps for processing the medical data are also introduced.Additionally,the methods for the definition and application of the DMDL model are presented for three specific medical scenarios,i.e.,the management of the heterogeneous data,copyright protection for medical data and the secure utilization of sensitive data.The advantage of the proposed DMDL model is demonstrated by comparing with the models which are being currently adopted in healthcare system.

A Trust-Based Hierarchical Consensus Mechanism for Consortium Blockchain in Smart Grid

As the smart grid develops rapidly,abundant connected devices offer various trading data.This raises higher requirements for secure and effective data storage.Traditional centralized data management does not meet the above requirements.Currently,smart grid with conventional consortium blockchain can solve the above issues.However,in the face of a large number of nodes,existing consensus algorithms often perform poorly in terms of efficiency and throughput.In this paper,we propose a trust-based hierarchical consensus mechanism(THCM)to solve this problem.Firstly,we design a hierarchical mechanism to improve the efficiency and throughput.Then,intra-layer nodes use an improved Raft consensus algorithm and inter-layer nodes use the Byzantine Fault Tolerance algorithm.Thirdly,we propose a trust evaluation method to improve the election process of Raft.Finally,we implement a prototype system to evaluate the performance of THCM.The results demonstrate that the consensus efficiency is improved by 19.8%,the throughput is improved by 12.34%,and the storage is reduced by 37.9%.

Raft Consensus Algorithm Based on Credit Model in Consortium Blockchain

As one of the underlying technologies of the blockchain,the consensus algorithm plays a vital role in ensuring security and efficiency.As a consensus algorithm for the private blockchain,Raft has better performance than the rest of the consensus algorithms,and it does not cause problems such as the concentrated hashing power,resource waste and fork.However,Raft can only be used in a non-byzantine environment with a small network size.In order to enable Raft to be used in a large-scale network with a certain number of byzantine nodes,this paper combines Raft and credit model to propose a Raft blockchain consensus algorithm based on credit model CRaft.In the node credit evaluation phase,RBF-based support vector machine is used as the anomaly detection method,and the node credit evaluation model is constructed.Then the Trust Nodes List(TNL)mechanism is introduced to make the consensus phase in a creditable network environment.Finally,the common node is synchronized to the consensus node to update the blockchain of the entire network.Experiments show that CRaft has better throughput and lower latency than the commonly used consortium blockchain consensus algorithm PBFT(Practical Byzantine Fault Tolerance).

A Consensus and Incentive Program for Charging Piles Based on Consortium Blockchain

Charging piles are used for charging electric vehicles and are directly accessible to users in an energy internet entrance,while playing an important role in energy consumption.Currently,each enterprise constructs the center of operation and maintenance of their systems independently,along with their respective APP payment programs.This results in high operating costs,poor user experience,and low utilization rate of the pile,which limits the promotion and popularization of electric vehicles.To overcome this limitation,there is a need for a multi-center,fair,and transparent consortium blockchain,which can conform to the application requirements of a unified payment system and accommodate a range of diverse enterprise charging piles.In this paper,the design for a consensus and incentive program for consortium blockchain is presented.First,the application status of blockchain in an energy internet is described.Then,the logical structure and hierarchical model of the consortium blockchain are analyzed.Next,multicycle accounting and limiting the amount of accounting nodes in each round is presented to ensure the overhead of consensus remain constant.Finally,the accounting incentive mechanism and the bidding encouragement strategy based on“electric beans”are designed.

UCBIS:An improved consortium blockchain information system based on UBCCSP

Blockchain technologies have been applied in many areas,from economics,the internet of things to the industrial internet.In order to solve the issue that the Hyperledger Fabric does not currently support Chinese Commercial Cryptographic(CCC)algorithms,we extended the Blockchain Cryptographic Service Provider(BCCSP)module in the Hyperledger Fabric by upgrading the original BCCSP module to support the CCC algorithms SM2 and SM3.Furthermore,we designed a transaction process by using UBCCSP(Upgraded BCCSP),and a new smart contract also has been presented.After that,an improved consortium blockchain information system based on UBCCSP named UCBIS(Consortium Blockchain Information System based on UBCCSP)is proposed.In the Hyperledger Fabric transaction process,the identity information and transaction data are protected by the SM2 and SM3 algorithms,moreover,SM3 is also used in the construction process of smart contracts.Our smart contracts reduce the total data amount and improve query efficiency.Finally,the information query system based on UBCCSP is implemented.After being tested and analyzed,the average time for every query is only 31.162 ms in the blockchain system,which has better performance and higher query efficiency.