In LEO(Low Earth Orbit)satellite communication systems,the satellite network is made up of a large number of satellites,the dynamically changing network environment affects the results of distributed computing.In orde...In LEO(Low Earth Orbit)satellite communication systems,the satellite network is made up of a large number of satellites,the dynamically changing network environment affects the results of distributed computing.In order to improve the fault tolerance rate,a novel public blockchain consensus mechanism that applies a distributed computing architecture in a public network is proposed.Redundant calculation of blockchain ensures the credibility of the results;and the transactions with calculation results of a task are stored distributed in sequence in Directed Acyclic Graphs(DAG).The transactions issued by nodes are connected to form a net.The net can quickly provide node reputation evaluation that does not rely on third parties.Simulations show that our proposed blockchain has the following advantages:1.The task processing speed of the blockchain can be close to that of the fastest node in the entire blockchain;2.When the tasks’arrival time intervals and demanded working nodes(WNs)meet certain conditions,the network can tolerate more than 50%of malicious devices;3.No matter the number of nodes in the blockchain is increased or reduced,the network can keep robustness by adjusting the task’s arrival time interval and demanded WNs.展开更多
联盟链技术是我国区块链发展和应用的主阵地.传统联盟链应用存在底层技术平台异构、应用技术门槛高、成链成本大、运维监管难等瓶颈问题,限制了区块链技术与应用发展.提出一种区块链公用基础设施——区块链服务网络(blockchain-based se...联盟链技术是我国区块链发展和应用的主阵地.传统联盟链应用存在底层技术平台异构、应用技术门槛高、成链成本大、运维监管难等瓶颈问题,限制了区块链技术与应用发展.提出一种区块链公用基础设施——区块链服务网络(blockchain-based service network,BSN)的构建机理,阐述BSN的技术架构和实现机制.BSN已于2020年4月在中国正式商用,能够显著降低区块链开发、部署、运维、互通和监管成本,有利于区块链技术向企业、政府、行业等领域推广应用,为我国新型智慧城市建设和数字经济发展提供了可信可控的公用基础设施和服务载体.展开更多
While users enjoy the convenience of data outsourcing in the cloud,they also face the risks of data modification and private information leakage.Searchable encryption technology can perform keyword searches over encry...While users enjoy the convenience of data outsourcing in the cloud,they also face the risks of data modification and private information leakage.Searchable encryption technology can perform keyword searches over encrypted data while protecting their privacy and guaranteeing the integrity of the data by verifying the search results.However,some associated problems are still encountered,such as the low efficiency of verification and uncontrollable query results.Accordingly,this paper proposes a Privacy-Preserving Searchable Encryption(PPSE)scheme based on public and private blockchains.First,we store an encrypted index in a private blockchain while outsourcing corresponding encrypted documents to a public blockchain.The encrypted documents are located through the encrypted index.This method can reduce the storage overhead on the blockchains,and improve the efficiency of transaction execution and the security of stored data.Moreover,we adopt a smart contract to introduce a secondary verification access control mechanism and restrict data users’access to the private blockchain through authorization for the purpose of guaranteeing data privacy and the correctness of access control verification.Finally,the security analysis and experimental results indicate that compared with existing schemes,the proposed scheme can not only improve the security of encrypted data but also guarantee the efficiency of the query.展开更多
基金funded in part by the National Natural Science Foundation of China (Grant no. 61772352, 62172061, 61871422)National Key Research and Development Project (Grants nos. 2020YFB1711800 and 2020YFB1707900)+2 种基金the Science and Technology Project of Sichuan Province (Grants no. 2021YFG0152, 2021YFG0025, 2020YFG0479, 2020YFG0322, 2020GFW035, 2020GFW033, 2020YFH0071)the R&D Project of Chengdu City (Grant no. 2019-YF05-01790-GX)the Central Universities of Southwest Minzu University (Grants no. ZYN2022032)
文摘In LEO(Low Earth Orbit)satellite communication systems,the satellite network is made up of a large number of satellites,the dynamically changing network environment affects the results of distributed computing.In order to improve the fault tolerance rate,a novel public blockchain consensus mechanism that applies a distributed computing architecture in a public network is proposed.Redundant calculation of blockchain ensures the credibility of the results;and the transactions with calculation results of a task are stored distributed in sequence in Directed Acyclic Graphs(DAG).The transactions issued by nodes are connected to form a net.The net can quickly provide node reputation evaluation that does not rely on third parties.Simulations show that our proposed blockchain has the following advantages:1.The task processing speed of the blockchain can be close to that of the fastest node in the entire blockchain;2.When the tasks’arrival time intervals and demanded working nodes(WNs)meet certain conditions,the network can tolerate more than 50%of malicious devices;3.No matter the number of nodes in the blockchain is increased or reduced,the network can keep robustness by adjusting the task’s arrival time interval and demanded WNs.
文摘联盟链技术是我国区块链发展和应用的主阵地.传统联盟链应用存在底层技术平台异构、应用技术门槛高、成链成本大、运维监管难等瓶颈问题,限制了区块链技术与应用发展.提出一种区块链公用基础设施——区块链服务网络(blockchain-based service network,BSN)的构建机理,阐述BSN的技术架构和实现机制.BSN已于2020年4月在中国正式商用,能够显著降低区块链开发、部署、运维、互通和监管成本,有利于区块链技术向企业、政府、行业等领域推广应用,为我国新型智慧城市建设和数字经济发展提供了可信可控的公用基础设施和服务载体.
基金supported by the National Natural Science Foundation of China (No.61972073)the Key Program of Natural Science Foundation of Hebei Province of China (No.F2019201290)the Natural Science Foundation of Hebei Province of China (No.F2018201153).
文摘While users enjoy the convenience of data outsourcing in the cloud,they also face the risks of data modification and private information leakage.Searchable encryption technology can perform keyword searches over encrypted data while protecting their privacy and guaranteeing the integrity of the data by verifying the search results.However,some associated problems are still encountered,such as the low efficiency of verification and uncontrollable query results.Accordingly,this paper proposes a Privacy-Preserving Searchable Encryption(PPSE)scheme based on public and private blockchains.First,we store an encrypted index in a private blockchain while outsourcing corresponding encrypted documents to a public blockchain.The encrypted documents are located through the encrypted index.This method can reduce the storage overhead on the blockchains,and improve the efficiency of transaction execution and the security of stored data.Moreover,we adopt a smart contract to introduce a secondary verification access control mechanism and restrict data users’access to the private blockchain through authorization for the purpose of guaranteeing data privacy and the correctness of access control verification.Finally,the security analysis and experimental results indicate that compared with existing schemes,the proposed scheme can not only improve the security of encrypted data but also guarantee the efficiency of the query.
