With the rapid development of mobile communications and continuous network expansion, wireless resources become increasingly scarce. Based on the blockchain, the blockchain radio access network (B-RAN) has recently emerged as a promising architecture for the next generation mobile communication system. Via in-depth merging of blockchain and wireless communication technologies, the B-RAN presents a new paradigm to design future mobile networks. This paper briefly introduces the basic concept and workflow of the B-RAN, and provides several technical solutions for the B-RAN in order to satisfy different scenarios and needs. Furthermore, the security performance of the B-RAN is theoretically analyzed. This paper also designs a dedicated framework of the B-RAN and implements its core modules to test its practical performance. The test results show that the B-RAN has a noteworthy advantage in throughput under the scenario of multiple subnetworks. Compared with other blockchain architectures, the B-RAN has a significantly lower latency of service deployment and is able to achieve the balance dynamically between its security level and service latency.
Low throughput has been the biggest obstacle to large-scale blockchain applications. During the past few years, researchers have proposed various schemes for improving the systems’ throughput. However, due to the inherent inefficiency and defects of the Internet, especially in data broadcasting tasks, these efforts have all proved unsatisfactory. In this paper, we propose a novel blockchain protocol which utilizes the satellite broadcasting network instead of the traditional Internet for data broadcasting and consensus tasks. An automatic resumption mechanism is also proposed to solve the unique communication problems of satellite broadcasting. Simulation results show that the proposed algorithm has a lower communication cost and can greatly improve the throughput of the blockchain system. Theoretical estimation of a satellite broadcasting enabled blockchain system’s throughput is 6 000 000 TPS with a satellite bandwidth of 20 Gbps.
The development of traffic analysis technology makes many covert communication methods based on the TCP/IP architecture face many threats. The subliminal channel is one that can realize covert communication by using cryptographic systems such as digital signatures and authentication. During the digital signature process, both parties of the communication can transmit secret information, and no one except the two parties knows the existence of the secret information. As a new generation technology, the blockchain adopts a distributed structure, and its openness, data tampering and security make it an effective carrier for constructing subliminal channels. This article introduces Monero, a new type of digital currency that uses blockchain technology, and constructs two subliminal channels in Monero. The first is based on the sharing of keys between signers and verifiers. The second does not share keys. Covert communication is achieved through these two subliminal channels.
The blockchain has typical features such as decentralization of accounts, data irrevocability and transparency of information, which solves to a certain extent the collaboration and value flow between individuals who do not trust each other. However, the public verifiability of the blockchain poses security challenges for user privacy, while its performance issues, especially in terms of transaction throughput and scalability, also limit further development of blockchain technology. This paper researches and discusses the two major aspects of blockchain privacy protection and scaling technologies. First, it outlines the Bitcoin and ETH technologies in the blockchain and the comparison between them; then, it introduces several typical blockchain-oriented key technologies and development status of privacy protection such as ring signature, zero knowledge proof, secure multi-party computing, homomorphic commitment and subvector commitment. Similarly, the key technologies and case studies of blockchain scale-up are introduced from both up and down the chain to break through the two major bottlenecks in the development of blockchain privacy protection and scalability, so that the blockchain has a smart contract function, under the premise of protecting user privacy with high transaction throughput and scalability, to meet the actual needs of a wide range of fields such as finance, education, social management and industrial logistics, is the future direction of development of the blockchain.
The regulation of digital currency is currently a hot topic. At present, there are some digital currencies that protect user privacy well, but are unable to be regulated, which hinders the further application of these digital currencies. By taking Monero as an example, this paper proposes an improved solution based on a group signature and a knowledge proof for CryptoNote, the underlying technology of Monero, which can achieve the regulation of Monero. The group manager can trace a suspected transaction, determine the real identity of its sender, find the complete transaction list of the sender, and revoke the private key to freeze the coins of the sender when necessary.
Recent advances in cloud computing are further pushing forward the development of the technique known as searchable encryption. However, existing encrypted search schemes mainly consider a centralized setting, where a search is conducted in a traditional client-server model. How to apply searchable encryption schemes to an untrusted distributed setting like the blockchain environment remains to be explored. Meanwhile, the advanced security property like forward security is posing new challenges that traditional technologies are no longer sufficient to cope with. In this work, we explore the potential of the blockchain technique and propose a novel dual index structure for forward-secure encrypted search with dynamic file updates. We show how to synthesize this design strategy in the context of blockchain-based storage systems and achieve both optimal search and update complexity. We also propose a verification scheme to verify the correctness of search results and customize an encrypted on-chain checklist to achieve strong data protection and lower the blockchain overhead. We implement the prototype on a Redis cluster and conduct performance evaluations on the Amazon Cloud. Extensive experiments demonstrate the security and efficiency of the design.
A mechanism for proof-of-reputation consensus for blockchain validator nodes is proposed to deal with existing blockchain consensus mechanism's lack of evaluation of validator node's reputation and the inability to effectively prevent Byzantine behaviors. First, an interactive indicator is designed for validator nodes to represent their contribution in the blockchain network, which will be used as the reputation benchmark of validator nodes. Second, another reliability indicator is designed for validator nodes from the aspects of online time and the number of valid blocks, which will be used as the weight of the reputation improvement of validator nodes. Finally, the reputation of validator nodes of the current round is comprehensively calculated, and a set of producing validators of the current round is selected based on the reputation ranking. Experimental results show that the proof of reputation consensus mechanism has certain advantages in dealing with malicious and lazy behaviors, and that it can also reduce the impact of capital and energy consumption on the blockchain consensus mechanism while ensuring the validity of the credit evaluation.
In the traditional Service Oriented Architecture(SOA),evaluations of services are results from accumulated remarks, which means that they lack real-time feedbacks. In this paper, we propose an advanced architecture combined by SOA and block-chain. We take the advantage of the stable time-slot generated by the consensus algorithm to clock the service pool, making it possible to evaluate the real-time states of services. Moreover, we propose a mathematical model based on the Markov Chain to assess and predict the compatibility of a service in a time-slot. And we assess and evaluate the distribution of compatibility by bringing in four well-known consensus algorithms (Bitcoin’s PoW, PPCoin’s DPoS, Fabric PBFT, PBFT+DPoS) which generate different lengths of time-slots. The result shows that our compatibility assessment model works well and that the distribution varies with different consensus algorithms with the rankings of effects as follows: PoW,PBFT,DPoS, and PBFT+DPoS.
The bio-inspired detection system has aroused wide attention in the fields of 5G and the Internet of things for the intrinsic features (e.g, inherent adaptivity, resiliency, and global intelligence). This paper first analyzes the architectural composition and potential security risks of such bio-inspired detection systems. Traditional distributed detection systems may suffer from man-in-the-middle attacks and collusion attacks. In this paper, a blockchain-based distributed security detection method, BDAF (Blockchain-based Digital Ants Framework), is proposed to address these problems. This method uses aggregate signatures to improve the privacy of the system, encrypt detection data, and conducts distributed threat assessment based on a consensus mechanism. The BDAF transforms the bio-inspired threat detection system into a blockchain application, which effectively improves the robustness by taking advantage of the structural benefits of the blockchain.
The emergence of block withholding attack poses a threat to the security of the Bitcoin system and seriously damages the honest miners' right to obtain fair benefits. In this paper, we study this attack by building an evolutionary game model to reveal the dynamic evolution trend of players’ strategies and to deduce the evolutionary stability strategies with the help of replicator dynamics. We also analyze the strategy choices of miners under the different supervision and punishment measures of the pool and put forward corresponding suggestions for the pool. Finally, we conduct numerical simulation by Matlab to verify the effectiveness of our analysis by the evolutionary game model. The simulation results show that the mining pool can effectively mitigate the block withholding attack at a relatively low frequency of supervision and high penalty.
Aiming at the problem of privacy protection when users transact or store data on the block chain, a ring signature algorithm which can be applied to a block chain system is proposed. First, the traditional ring signature algorithm is improved to generate keys based on the multi-PKG, which meets the requirements of the blockchain distributed trust environment. Second, different roles are assigned to the nodes in the block chain, and intelligent contract technology is used to control the generation and verification process of the signature. Finally, relevant experiments are carried out on the improved algorithm. Analysis and experimental results show that the algorithm proposed in this paper can protect the identity privacy of nodes in the block chain, has a good fault tolerance under the premise of ensuring efficiency, and can operate normally in the case of partial node failure.
The existing blockchain data covert transmission scheme is faced with the problems of poor concealment, small channel capacity and low efficiency. This paper designs a new model for separating the data embedding mechanism from the transaction filtering mechanism, and proposes a new filtering algorithm based on the address dynamic label. In this scheme,the HMAC algorithm is used to construct the special address label, so that the receiving party can effectively screen the special transaction carrying the concealed information from the massive data in the blockchain ledger, and realize the concealed data transmission in the open blockchain scenario. Simulation results show that the proposed scheme can realize the hidden transmission of data in the real bitcoin network. The concealment and efficiency of the scheme are better than those of the traditional scheme.
Electronic health records contain the occurrence, development and treatment of patients' diseases, and have a high medical value. Due to the privacy and sensitivity of medical data, data sharing and privacy protection are key issues for electronic medical records. Aiming at the characteristics of decentralization and tamper resistance of the blockchain, an electronic medical record sharing model based on the blockchain is proposed. First, a private chain and an alliance chain are built to store the encrypted electronic medical and electronic medical's security index records of users, respectively. Second, a combination of distributed key generation technology and a type and identity based proxy re-encryption scheme is proposed, and a multi-center scheme is designed as a data sharing protocol, which uses the entrusted-proof-of-rights-and-interests algorithm to select proxy nodes. Finally, an analysis and calculation of the proposed scheme and the existing scheme in various aspects such as tamper resistance and attack resistance are conducted. The result shows that the scheme consumes less energy in terms of communication overhead and computing power so that it can achieve the safe sharing of medical data effectively.
With the rapid development of information digitization, a great deal of judicial evidence electronization also brings a lot of issues such as data security and trust. To face the growing demand for electronic data storage, the traditional method of depositing has gradually revealed its shortcomings, such as high cost, low efficiency, and difficulty in obtaining credit, so how to ensure the security and credibility of video evidence, voice recording, electronic contract, and other electronic judicial evidence has become a problem that must be solved. In order to solve these problems, this paper designs a blockchain electronic certificate storage system based on the Hyperledger Fabric. Through the combination of the blockchain consensus mechanism and the interstellar file system, the electronic evidence storage problem is solved while ensuring the safety and credibility of the electronic evidence and the traceability of responsibilities. Finally, an access permission control scheme is designed to ensure the privacy of user data.
Aiming at the problems of safety and privacy threats in establishing autonomous vehicle platoons in vehicle social networks, which would hinder the widespread adoption of platoons, a scheme for recommendation of autonomous vehicle platoon members by combining the blockchain and vehicle social networks is proposed. A series of security protocols to form a privacy platoon recommendation algorithm is first proposed. Second, the homomorphic encryption and secure multi-party computing are integrated to protect data security and reduce the risk of privacy leakage. Finally, the blockchain and vehicle social networks are combined to achieve efficient system operation. The proof of security shows that the proposed scheme meets the requirement of privacy protection. Besides, experimental results show that the cost of communication and that of calculation in the proposed scheme are both acceptable and reliable and effective for the formation of the platoon.
In this paper, in order to improve the efficiency of designing the dual-passband filter, the extraction method of the coupling matrix of the dual-passband filter is studied based on the duplexer theory, and a dual-passband cavity filter is designed. First, the basic theory of the coupling matrix is analyzed, and then the method for extracting the coupling matrix based on the duplexer is studied. Finally, the corresponding coupling matrix is verified theoretically by the circuit model, and the design and simulation of the filter are performed using electromagnetic simulation software. The simulation results show that the dual-passband filter designed in this paper has the characteristics of a flexible and controllable passband, a low insertion loss, and good out-of-band rejection. The proposed method can improve the efficiency of designing the dual-passband filter.
Due to the inseparability of measurements in neighborhood scenarios, the tracking performance of the traditional extended target tracking algorithm would degrade. In this paper, a new extended target tracking algorithm based on one step data association is proposed to solve the problem. First, the algorithm models the target with a multiplicative noise model. And then, the one step data association method in the Joint Probabilistic Data Association (JPDA) theory is combined with a Generalized Labeled Multi-Bernoulli (GLMB) filter. Simulation results show that the algorithm can track the target in cross and neighborhood scenarios effectively and that it is superior to the traditional extended target tracking algorithms based on measurement partition in estimation accuracy.
In order to solve the problem of multicast wireless secure communication with unknown locations of the eavesdroppers, a secure communication synthesis scheme was proposed based on the frequency diverse arrays. By studying the frequency diverse arrays model and analyzing the beam pattern, a random frequency diverse array is constructed at the transmitter. At the same time, combined with the added artificial noise baseband signal processing method, the maximizing artificial noise energy method is designed to optimize the beamforming weighted vector of each multicast group, so as to improve the security performance of the multicast system. Numerical results show that the scheme realizes secure communication of a multicast system and can precisely control the signal energy received by legitimate users.
Considering the shortcomings of the white-box CLEFIA algorithm (Su-white-box CLEFIA algorithm) implemented by Su Shuai et al with perturbations technology, the analytical method of Michiels et al can recover the master key in a time complexity of no more than 2.5×229. In order to ensure that the CLEFIA algorithm runs safely in a white-box attack context, a white-box implementation scheme (new white-box CLEFIA algorithm) based on the lookup table technology is proposed, which requires 36.034MB of memory space. The white-box diversity values corresponding to the two types of lookup tables in this scheme are 2829 and 2813, respectively, and the time complexity for the affine equivalent algorithm can reach O(276). This scheme can effectively resist code extraction attacks, key extraction attacks, attacks by Michiels et al and analysis by De Mulder.