With the rapid development of cloud services, huge volume of data is shared via cloud computing. Although cryptographic techniques have been utilized to provide data confidentiality in cloud computing, current mechanisms cannot enforce privacy concerns over ciphertext associated with multiple owners, which makes co-owners unable to appropriately control whether data disseminators can actually disseminate their data. In this paper, we propose a secure data group sharing and conditional dissemination scheme with multi-owner in cloud computing, in which data owner can share private data with a group of users via the cloud in a secure way, and data disseminator can disseminate the data to a new group of users if the attributes satisfy the access policies in the ciphertext. We further present a multiparty access control mechanism over the disseminated ciphertext, in which the data co-owners can append new access policies to the ciphertext due to their privacy preferences. Moreover, three policy aggregation strategies, including full permit, owner priority and majority permit, are provided to solve the privacy conflicts problem caused by different access policies. The security analysis and experimental results show our scheme is practical and efficient for secure data sharing with multi-owner in cloud computing.

Cloud computing has become increasingly popular among users and businesses around the world. Although cryptographic techniques can provide data protection for users in public cloud, several issues also remain problematic, such as secure data group dissemination and fine-grained access control of time-sensitive data. In this paper, we propose an identity-based data group sharing and dissemination scheme in public cloud, in which data owner could broadcast encrypted data to a group of receivers at one time by specifying these receivers' identities in a convenient and secure way. In order to achieve secure and flexible data group dissemination, we adopt attribute-based and timed-release conditional proxy re-encryption to guarantee that only data disseminators whose attributes satisfy the access policy of encrypted data can disseminate it to other groups after the releasing time by delegating a re-encryption key to cloud server. The re-encryption conditions are associated with attributes and releasing time, which allows data owner to enforce fine-grained and timed-release access control over disseminated ciphertexts. The theoretical analysis and experimental results show our proposed scheme makes a tradeoff between computational overhead and expressive dissemination conditions.

Benefiting from cloud computing and mobile devices, a huge number of media contents, such as videos are shared in mobile networks. Although scalable video coding can be utilized to provide flexible adaptation, the cloud poses a serious threat to media privacy. In this paper, we propose a privacy-preserving multi-dimensional media sharing scheme named SMACD in mobile cloud computing. First, each media layer is encrypted with an access policy based on attribute-based encryption, which guarantees media confidentiality as well as fine-grained access control. Then, we present a multi-level access policy construction with secret sharing scheme. It ensures that the mobile consumers who obtain a media layer at a higher access level must satisfy the access trees of its child layers at the lower access level, which is compatible with the characteristics of multi-dimensional media and also reduces the complexity of access policies. Moreover, we introduce decentralized key servers to achieve both intra-server and inter-server deduplication by associating different access policies into the same encrypted media. Finally, we conduct experimental evaluation on mobile device and cloud platform with real-world datasets. The results indicate that SMACD protects media privacy against cloud media center and unauthorized parties, while incurring less computational and storage cost.

The multimedia-based e-Learning methodology provides virtual classrooms to students. The teacher uploads learning materials, programming assignments and quizzes on university’ Learning Management System (LMS). The students learn lessons from uploaded videos and then solve the given programming tasks and quizzes. The source code plagiarism is a serious threat to academia. However, identifying similar source code fragments between different programming languages is a challenging task. To solve the problem, this paper proposed a new plagiarism detection technique between C++ and Java source codes based on semantics in multimedia-based e-Learning and smart assessment methodology. First, it transforms source codes into tokens to calculate semantic similarity in token by token comparison. After that, it finds semantic similarity in scalar value for the complete source codes written in C++ and Java. To analyse the experiment, we have taken the dataset consists of four (4) case studies of Factorial, Bubble Sort, Binary Search and Stack data structure in both C++ and Java. The entire experiment is done in R Studio with R version 3.4.2. The experimental results show better semantic similarity results for plagiarism detection based on comparison. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

The Software Defined Network (SDN) is merged in the Internet of Things (IoT) to interconnect large and complex networks. It is used in the education system to interconnect students and teacher by heterogenous IoT devices. In this paper, the SDN-based IoT model for students’ Interaction is proposed which interconnects students to a teacher in a smart city environment. The students and teachers are free to move to anywhere, anytime and with any hardware. An architecture model for students’ teacher’s interaction in IoT is proposed which shows the details procedure about the interaction of teacher with students for electronic assessment. The SDN solves the scalability and interoperability issues between their heterogenous IoT devices. A Methodology for Students’ Answer Assessment using Latent Semantic Analysis (LSA) is proposed which calculates the semantic similarity between teacher’s question and students’ answers. The LSA is used to calculate semantic similarity between text documents. It is used to mark the students’ answers automatically by semantics. The Students’ can see results through their IoT devices just after finishing the examination with more accurate marks We have collected fifty (50) undergraduate students’ data from Learning Management System (LMS) of Virtual University (VU) of Pakistan. The experiment is implemented on eighteen (18) students’ answers in R Studio with R version 3.4.2. Teachers are provided with four (4) bins of the mark while the proposed method assigns accurate marks. The experimental results show that the proposed methodology gave accurate results as compared to teacher’s marks. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

This research aims to an electronic assessment (e-assessment) of students' replies in response to the standard answer of teacher's question to automate the assessment by WordNet semantic similarity. For this purpose, a new methodology for Semantic Similarity through WordNet Semantic Similarity Techniques (SS-WSST) has been proposed to calculate semantic similarity among teacher' query and student's reply. In the pilot study-1 42 words' pairs extracted from 8 students' replies, which marked by semantic similarity measures and compared with manually assigned teacher's marks. The teacher is provided with 4 bins of the mark while our designed methodology provided an exact mcamre of marks. Secondly, the source codes plagiarism in students' assignments provide smart e-assessment. The WordNet semantic similarity techniques are used to investigate source code plagiarism in binary search and stack data structures programmed in C++, Java, C# respectively.

We proposed a new type of bitcoin withholding attack named block withholding delay (BWD). It is different from the traditional withholding attacks which always drop valid blocks. BWD attackers never discard blocks but they delay the submissions of blocks to the pool managers, resulting the pool failed in the mining competitions and loss of rewards. We analyzed the optimum strategy of a BWD attacker who split its computing power into two parts, one was utilized to launch BWD attacks on the victim pools, while the other part was used for solo mining. We present detailed quantitative analysis of the maximum incentive that an attacker can earn by carefully splitting its computing power, and demonstrated that the attacker can obtain higher incentives than its contribution to the network in different conditions. Furthermore, we proposed a countermeasure against BWD based on the interval type-2 Takagi-Sugeno-Kang fuzzy inference system (IT2-TSK-FIS). The principle is to modify the private payoff scheme of pools to increase the risk of losing revenues of the rogue miners who deliberately delay block submissions. The scheme dealing the uncertain cause of block delay using fuzzy inference, and it is so designed that it does not require modifications of public mining protocols or data structures of the bitcoin network, which makes it applicable in practical pools. © 2020 the Author(s), licensee AIMS Press.

本研究通过构建数字虚拟资产安全管理与交易原型系统，为理论及方法提供验证手段，为其改进和提高提供实验数据；同时，通过研究系统的典型应用场景、部署方式、实现策略等，为大规模示范应用、技术推广、产品研发等提供依据。本研究将严格基于课题1数字虚拟资产基础数学模型、课题2数字虚拟资产安全管理与交易技术、课题3数字虚拟资产安全威胁感知方法和课题4数字虚拟资产动态风险控制机制的理论和方法构建相应的原型系统，以达到项目成果验证的目的。具体的研究内容包括研究数字虚拟资产安全管理与交易原型系统体系架构、典型应用场景、部署方式、实现策略等；基于课题1数字虚拟资产基础数学模型和课题2数字虚拟资产安全管理与交易技术的理论和方法，研究数字虚拟资产安全应用系统，包括用户身份认证和资产登记、安全存储和使用控制、以及安全交易和追踪溯源3 大子系统；基于课题1数字虚拟资产基础数学模型、课题3数字虚拟资产安全威胁感知方法和课题4数字虚拟资产动态风险控制机制的理论和方法，研究数字虚拟资产威胁管控系统，包括数字虚拟资产安全威胁发现、以及数字虚拟资产动态风险控制2大子系统；研究利用原型系统进行项目成果验证的方法，包括人机界面的交互形式，以方便模型的调试、仿真，以及系统参数的调整和分析等工作，为项目理论及方法验证、改进和提高提供实验数据。 This project provides a verification method for the theory and method by constructing a digital virtual asset security management and trading,and provides experimental data for its improvement and enhancement.At the same time,by studying the typical application scenarios,deployment mode,and implementation strategies of the system,Provide a basis for large-scale demonstration applications,technology promotion,product development and so on.This project will build a corresponding prototype system based on the theories and methods of project 1 to project 4,so as to achieve the purpose of project results verification.The specific research contents include research on digital virtual asset security management and transaction prototype system architecture,typical application scenarios,deployment mode,implementation strategies,etc.;Based on the theory and method of project 1 and project 2,study digital virtual asset security application systems,including three sub-systems:identity authentication and asset registration,secure storage and usage control,and secure transaction and traceability;research on digital virtual asset threat management systems,including digital virtual asset security,Based on the theories and methods of project 1,project 3 and project 4,this paper studies the digital virtual asset threat management and control system,including digital virtual asset security threat detection and digital virtual asset dynamic risk control sub-system.The research USES the prototype system to carry on the project achievement verification method,including the man-machine interface interactive form,facilitates the model debugging,the simulation,as well as the system parameter adjustment and the analysis and so on work,provides the experimental data for the project theory and the method verification,the improvement and the enhancement.

The security of wireless sensor networks (WSN) has become a great challenge due to the transmission of sensor data through an open and wireless network with limited resources. In the paper, we discussed a lightweight security scheme to protect the confidentiality of data transmission between sensors and an ally fusion center (AFC) over insecure links. For the typical security problem of WSN’s binary hypothesis testing of a target’s state, sensors were divided into flipping and non-flipping groups according to the outputs of a pseudo-random function which was held by sensors and the AFC. Then in order to prevent an enemy fusion center (EFC) from eavesdropping, the binary outputs from the flipping group were intentionally flipped to hinder the EFC’s data fusion. Accordingly, the AFC performed inverse flipping to recover the flipped data before data fusion. We extended the scheme to a more common scenario with multiple scales of sensor quantification and candidate states. The underlying idea was that the sensor measurements were randomly mapped to other quantification scales using a mapping matrix, which ensured that as long as the EFC was not aware of the matrix, it could not distract any useful information from the captured data, while the AFC could appropriately perform data fusion based on the inverse mapping of the sensor outputs. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.

Cloud-Assisted Internet of Vehicles (IoV)which merges the advantages of both cloud computing and Internet of Things that can provide numerous online services, and bring lots of benefits and conveniences to the connected vehicles. However, the security and privacy issues such as confidentiality, access control and driver privacy may prevent it from being widely utilized for message dissemination. Existing attribute-based message encryption schemes still bring high computational cost to the lightweight vehicles. In this paper, we introduce a secure and privacy-preserving dissemination scheme for warning message in cloud-Assisted IoV. Firstly, we adopt attribute-based encryption to protect the disseminated warning message, and present a verifiable encryption and decryption outsourcing construction to reduce the computational overhead on vehicles. Secondly, we present a conditional privacy preservation mechanism which utilizes anonymous identity-based signature technique to ensure anonymous vehicle authentication and message integrity checking, and also allows the trusted authority to trace the real identity of malicious vehicle. We further achieve batch verification to improve the authentication efficiency. The analysis indicate that our scheme gains more security properties and reduces the computational overhead on the vehicles. © 2019 IEEE.