Biblio

With the rapid development of cloud storage technology, an increasing number of enterprises and users choose to store data in the cloud, which can reduce the local overhead and ensure safe storage, sharing, and deletion. In cloud storage, safe data deletion is a critical and challenging problem. This paper proposes an assured data deletion scheme based on multi-authoritative users in the semi-trusted cloud storage scenario (MAU-AD), which aims to realize the secure management of the key without introducing any trusted third party and achieve assured deletion of cloud data. MAU-AD uses access policy graphs to achieve fine-grained access control and data sharing. Besides, the data security is guaranteed by mutual restriction between authoritative users, and the system robustness is improved by multiple authoritative users jointly managing keys. In addition, the traceability of misconduct in the system can be realized by blockchain technology. Through simulation experiments and comparison with related schemes, MAU-AD is proven safe and effective, and it provides a novel application scenario for the assured deletion of cloud storage data.

With the advent of the era of Internet of Things (IoT), the increasing data volume leads to storage outsourcing as a new trend for enterprises and individuals. However, data breaches frequently occur, bringing significant challenges to the privacy protection of the outsourced data management system. There is an urgent need for efficient and secure data sharing schemes for the outsourced data management infrastructure, such as the cloud. Therefore, this paper designs a dual-server-based data sharing scheme with data privacy and high efficiency for the cloud, enabling the internal members to exchange their data efficiently and securely. Dual servers guarantee that none of the servers can get complete data independently by adopting secure two-party computation. In our proposed scheme, if the data is destroyed when sending it to the user, the data will not be restored. To prevent the malicious deletion, the data owner adds a random number to verify the identity during the uploading procedure. To ensure data security, the data is transmitted in ciphertext throughout the process by using searchable encryption. Finally, the black-box leakage analysis and theoretical performance evaluation demonstrate that our proposed data sharing scheme provides solid security and high efficiency in practice.

In the smart grid, the sharing of power data among various energy entities can make the data play a higher value. However, there may be unauthorized access while sharing data, which makes many entities unwilling to share their data to prevent data leakage. Based on blockchain and ABAC (Attribute-based Access Control) technology, this paper proposes an access control scheme, so that users can achieve fine-grained access control of their data when sharing them. The solution uses smart contract to achieve automated and reliable policy evaluation. IPFS (Interplanetary File System) is used for off-chain distributed storage to share the storage pressure of blockchain and guarantee the reliable storage of data. At the same time, all processes in the system are stored in the blockchain, ensuring the accountability of the system. Finally, the experiment proves the feasibility of the proposed scheme.

With the development of artificial intelligence, the need for data sharing is becoming more and more urgent. However, the existing data sharing methods can no longer fully meet the data sharing needs. Privacy breaches, lack of motivation and mutual distrust have become obstacles to data sharing. We design a privacy-preserving, decentralized data sharing method based on blockchain smart contracts, named PPDS. To protect data privacy, we transform the data sharing problem into a model sharing problem. This means that the data owner does not need to directly share the raw data, but the AI model trained with such data. The data requester and the data owner interact on the blockchain through a smart contract. The data owner trains the model with local data according to the requester's requirements. To fairly assess model quality, we set up several model evaluators to assess the validity of the model through voting. After the model is verified, the data owner who trained the model will receive reward in return through a smart contract. The sharing of the model avoids direct exposure of the raw data, and the reasonable incentive provides a motivation for the data owner to share the data. We describe the design and workflow of our PPDS, and analyze the security using formal verification technology, that is, we use Coloured Petri Nets (CPN) to build a formal model for our approach, proving its security through simulation execution and model checking. Finally, we demonstrate effectiveness of PPDS by developing a prototype with its corresponding case application.

In the era of big data, more and more users store data in the cloud. Massive amounts of data have brought huge storage costs to cloud storage providers, and data deduplication technology has emerged. In order to protect the confidentiality of user data, user data should be encrypted and stored in the cloud. Therefore, deduplication of encrypted data has become a research hotspot. Cloud storage provides users with data sharing services, and the sharing of encrypted data is another research hotspot. The combination of encrypted data deduplication and sharing will inevitably become a future trend. The current better-performing updateable block-level message-locked encryption (UMLE) deduplication scheme does not support data sharing, and the performance of the encrypted data de-duplication scheme that introduces data sharing is not as good as that of UMLE. This paper introduces the ciphertext policy attribute based encryption (CP-ABE) system sharing mechanism on the basis of UMLE, applies the CP-ABE method to encrypt the master key generated by UMLE, to achieve secure and efficient data deduplication and sharing. In this paper, we propose a permission verification method based on bilinear mapping, and according to the definition of the security model proposed in the security analysis phase, we prove this permission verification method, showing that our scheme is secure. The comparison of theoretical analysis and simulation experiment results shows that this scheme has more complete functions and better performance than existing schemes, and the proposed authorization verification method is also secure.

Recently, with the development of the cloud environment, users can store their data or share it with other users. However, various security threats can occur in data sharing systems in the cloud environment. To solve this, data sharing systems and access control methods using the CP-ABE method are being studied, but the following problems may occur. First, in an outsourcing server that supports computation, it is not possible to prove that the computed result is a properly computed result when performing the partial decryption process of the ciphertext. Therefore, the user needs to verify the message obtained by performing the decryption process, and verify that the data is uploaded by the data owner through verification. As another problem, because the data owner encrypts data with attribute-based encryption, the number of attributes included in the access structure increases. This increases the size of the ciphertext, which can waste space in cloud storage. Therefore, a ciphertext of a constant size must be output regardless of the number of attributes when generating the ciphertext. In this paper, we proposes a CP-ABE based data sharing system that provides signature-based verifiable outsourcing. It aims at a system that allows multiple users to share data safely and efficiently in a cloud environment by satisfying verifiable outsourcing and constant-sized ciphertext output among various security requirements required by CP-ABE.

In this paper, a blockchain based scheme is proposed to provide registration, mutual authentication and data sharing in wireless sensor network. The proposed model consists of three types of nodes: coordinators, cluster heads and sensor nodes. A consortium blockchain is deployed on coordinator nodes. The smart contracts execute on coordinators to record the identities of legitimate nodes. Moreover, they authenticate nodes and facilitate in data sharing. When a sensor node communicate and accesses data of any other sensor node, both nodes mutually authenticate each other. The smart contract of data sharing is used to provide a secure communication and data exchange between sensor nodes. Moreover, the data of all the nodes is stored on the decentralized storage called interplanetary file system. The simulation results show the response time of IPFS and message size during authentication and registration.

The ability to specify various policies with different overriding criteria allows for complex sets of sharing policies. This is particularly useful in situations in which data privacy depends on various properties of the data, and complex policies are needed to express the conditions under which data is protected. However, if overriding policy decisions constrain the affected data, decisions from overridden policies should not be suppressed completely, because they can still apply to subsets of the affected data. This article describes how a privacy policy framework can be extended with a mechanism to partially override decisions based on specified constraints. Our solution automatically generates complementary sets of decisions for both the overridden and the complementary, non-overridden subsets of the data, and thus, provides a means to specify a complex policies tailored to specific properties of the protected data.

The rapid development of cloud computing and the arrival of the big data era make the relationship between users and cloud closer. Cloud computing has powerful data computing and data storage capabilities, which can ubiquitously provide users with resources. However, users do not fully trust the cloud server's storage services, so lots of data is encrypted and uploaded to the cloud. Searchable encryption can protect the confidentiality of data and provide encrypted data retrieval functions. In this paper, we propose a time-controlled searchable encryption scheme with regular language over encrypted big data, which provides flexible search pattern and convenient data sharing. Our solution allows users with data's secret keys to generate trapdoors by themselves. And users without data's secret keys can generate trapdoors with the help of a trusted third party without revealing the data owner's secret key. Our system uses a time-controlled mechanism to collect keywords queried by users and ensures that the querying user's identity is not directly exposed. The obtained keywords are the basis for subsequent big data analysis. We conducted a security analysis of the proposed scheme and proved that the scheme is secure. The simulation experiment and comparison of our scheme show that the system has feasible efficiency.

Data sharing through the cloud is flourishing with the development of cloud computing technology. The new wave of technology will also give rise to new security challenges, particularly the data confidentiality in cloud-based sharing applications. Searchable encryption is considered as one of the most promising solutions for balancing data confidentiality and usability. However, most existing searchable encryption schemes cannot simultaneously satisfy requirements for both high search efficiency and strong security due to lack of some must-have properties, such as parallel search and forward security. To address this problem, we propose a variant searchable encryption with parallelism and forward privacy, namely the parallel and forward private searchable public-key encryption (PFP-SPE). PFP-SPE scheme achieves both the parallelism and forward privacy at the expense of slightly higher storage costs. PFP-SPE has similar search efficiency with that of some searchable symmetric encryption schemes but no key distribution problem. The security analysis and the performance evaluation on a real-world dataset demonstrate that the proposed scheme is suitable for practical application.

In cloud computing, the data is stored and retrieved through the internet. There are some common systems for cloud storage which includes the system for e-health records, the file stored on to the cloud server includes information which is private and sensitive, and the main focus should be that at the time when data gets shared, the content of the file should not be revealed. One of the ways to secure the file data is to simply encrypt the file, but on the other side, the authenticate user to which the data is shared will not be able to use it. User's time and memory are saved by Storing data in the cloud. The main issue is that the user loses total control over the once it is upload. This issue needs to be addressed while designing the system. In this paper the study of various mechanisms and techniques for data security stored over the cloud and hiding of the sensitive and private data. The paper also discusses the various issues faced while using or applying the techniques. Here, a system is proposed to use the encryption techniques, algorithms as well as secure cloud storage.

Cloud security has been of utmost concern for researchers and cloud deployers since the inception of cloud computing. Methods like PKI, hashing, encryption, etc. have proven themselves useful throughout cloud technology development, but they are not considered as a complete security solution for all kinds of cloud authentications. Moreover, data sharing in the cloud has also become a question of research due to the abundant use of data storage available on the cloud. To solve these issues, a Kerberos-based time-to-live (TTL) inspired data sharing and authentication mechanism is proposed on the cloud. The algorithm combines the two algorithms and provides a better cloud deployment infrastructure. It uses state-of-the-art elliptic curve cryptography along with a secure hashing algorithm (SHA 256) for authentication, and group-based time-to-live data sharing to evaluate the file-sharing status for the users. The result evaluates the system under different authentication attacks, and it is observed that the system is efficient under any kind of attack and any kind of file sharing process.

Cloud computing is a vast area within which large amounts of data are exchanged through cloud services and has fully grown with its on-demand technology. Due to these versatile cloud services, sensitive data will be stored on cloud storage servers and it is also used to dynamically control a number of problems: security, privacy, data privacy, data sharing, and integrity across cloud servers. Moreover, the legitimacy and control of data access should be maintained in this extended environment. So, one of the most important concepts of cryptographic techniques in cloud computing environment is Attribute Based Encryption (ABE). In this research work, data auditing or integrity checking is considered as an area of concern for securing th cloud storage. In data auditing approach, an auditor inspects and verifies the data file integrity without having any knowledge about the content of file and sends the verification report to the data owner. In this research, Elliptical Curve Modified RSA (ECMRSA) is proposed along with Modified MD5 algorithm which is used for attribute-based cloud data integrity verification, in which data user or owner uploads their encrypted data files at cloud data server and send the auditing request to the Third-Party Auditor (TPA) for verification of their data files. The Third-Party Auditor (TPA) challenges the data server for ensuring the integrity of data files on behalf of the data owners. After verification of integrity of data file auditor sends the audit report to the owner. The proposed algorithm integrates the auditing scheme with public key encryption with homomorphic algorithm which generates digital signature or hash values of data files on encrypted files. The result analysis is performed on time complexity by evaluating encryption time, GenProof time and VerifyProof Time and achieved improvement in resolving time complexity as compared to existing techiques.

The push for data sharing and data processing across organisational boundaries creates challenges at many levels of the software stack. Data sharing and processing rely on the participating parties agreeing on the permissible operations and expressing them into actionable contracts and policies. Converting these contracts and policies into a operational infrastructure is still a matter of research and therefore begs the question how should a digital data market place infrastructure look like? In this paper we investigate how communication fabric and applications can be tightly coupled into a multi-domain overlay network which enforces accountability. We prove our concepts with a prototype which shows how a simple workflow can run across organisational boundaries.

Security of cloud storage and sharing is concerned for years since a semi-trusted party, Cloud Server Provider (CSP), has access to user data on cloud server that may leak users' private data without constraint. Intuitively, an efficient solution of protecting cloud data is to encrypt it before uploading to the cloud server. However, a new requirement, data sharing, makes it difficult to manage secret keys among data owners and target users. Therefore conditional proxy broadcast re-encryption technology (CPBRE) is proposed in recent years to provide data encryption and sharing approaches for cloud environment. It enables a data owner to upload encrypted data to the cloud server and a third party proxy can re-encrypted cloud data under certain condition to a new ciphertext so that target users can decrypt re-encrypted data using their own private key. But few CPBRE schemes are applicable for a dynamic cloud environment. In this paper, we propose a new dynamic conditional proxy broadcast reencryption scheme that can be dynamic in system user setting and target user group. The initialization phase does not require a fixed system user setup so that users can join or leave the system in any time. And data owner can dynamically change the group of user he wants to share data with. We also provide security analysis which proves our scheme to be secure against CSP, and performance analysis shows that our scheme exceeds other schemes in terms of functionality and resource cost.

Generative Adversarial Network (GAN) has already made a big splash in the field of generating realistic "fake" data. However, when data is distributed and data-holders are reluctant to share data for privacy reasons, GAN's training is difficult. To address this issue, we propose private FL-GAN, a differential privacy generative adversarial network model based on federated learning. By strategically combining the Lipschitz limit with the differential privacy sensitivity, the model can generate high-quality synthetic data without sacrificing the privacy of the training data. We theoretically prove that private FL-GAN can provide strict privacy guarantee with differential privacy, and experimentally demonstrate our model can generate satisfactory data.

Large enterprises and organizations from both private and public sectors typically outsource a platform solution, as part of the Managed Security Services (MSSs), from 3rd party providers (MSSPs) to monitor and analyze their data containing cyber security information. Sharing such data among these large entities is believed to improve their effectiveness and efficiency at tackling cybercrimes, via improved analytics and insights. However, MSS platform customers currently are not able or not willing to share data among themselves because of multiple reasons, including privacy and confidentiality concerns, even when they are using the same MSS platform. Therefore any proposed mechanism or technique to address such a challenge need to ensure that sharing is achieved in a secure and controlled way. In this paper, we propose a new architecture and use case driven designs to enable confidential, flexible and collaborative data sharing among such organizations using the same MSS platform. MSS platform is a complex environment where different stakeholders, including authorized MSSP personnel and customers' own users, have access to the same platform but with different types of rights and tasks. Hence we make every effort to improve the usability of the platform supporting sharing while keeping the existing rights and tasks intact. As an innovative and pioneering attempt to address the challenge of data sharing in the MSS platform, we hope to encourage further work to follow so that confidential and collaborative sharing eventually happens among MSS platform customers.

With the construction and implementation of the government information resources sharing mechanism, the protection of citizens' privacy has become a vital issue for government departments and the public. This paper discusses the risk of citizens' privacy disclosure related to data sharing among government departments, and analyzes the current major privacy protection models for data sharing. Aiming at the issues of low efficiency and low reliability in existing e-government applications, a statistical data sharing framework among governmental departments based on local differential privacy and blockchain is established, and its applicability and advantages are illustrated through example analysis. The characteristics of the private blockchain enhance the security, credibility and responsiveness of information sharing between departments. Local differential privacy provides better usability and security for sharing statistics. It not only keeps statistics available, but also protects the privacy of citizens.

Advanced Persistent Threat (APT) having focused target along with advanced and persistent attacking skills under great concealment is a new trend followed for cyber-attacks. Threat intelligence helps in detecting and preventing APT by collecting a host of data and analyzing malicious behavior through efficient data sharing and guaranteeing the safety and quality of information exchange. For better protection, controlled access to intelligence information and a grading standard to revise the criteria in diagnosis for a security breach is needed. This paper analyses a threat intelligence sharing community model and proposes an improvement to increase the efficiency of sharing by rethinking the size and composition of a sharing community. Based on various external environment variables, it filters the low-quality shared intelligence by grading the trust level of a community member and the quality of a piece of intelligence. We hope that this research can fill in some security gaps to help organizations make a better decision in handling the ever-increasing and continually changing cyber-attacks.

Network threats often come from multiple sources and affect a variety of domains. Collaborative sharing and analysis of Cyber Threat Information (CTI) can greatly improve the prediction and prevention of cyber-attacks. However, CTI data containing sensitive and confidential information can cause privacy exposure and disclose security risks, which will deter organisations from sharing their CTI data. To address these concerns, the consortium of the EU H2020 project entitled Collaborative and Confidential Information Sharing and Analysis for Cyber Protection (C3ISP) has designed and implemented a framework (i.e. C3ISP Framework) as a service for cyber threat management. This paper focuses on the design and development of an API Gateway, which provides a bridge between end-users and their data sources, and the C3ISP Framework. It facilitates end-users to retrieve their CTI data, regulate data sharing agreements in order to sanitise the data, share the data with privacy-preserving means, and invoke collaborative analysis for attack prediction and prevention. In this paper, we report on the implementation of the API Gateway and experiments performed. The results of these experiments show the efficiency of our gateway design, and the benefits for the end-users who use it to access the C3ISP Framework.

Cloud computing has become an important and popular infrastructure for data storage and sharing. Typically, data owners outsource their massive data to a public cloud that will provide search services to authorized data users. With privacy concerns, the valuable outsourced data cannot be exposed directly, and should be encrypted before outsourcing to the public cloud. In this paper, we focus on k-Nearest Neighbor (k-NN) search over encrypted data. We propose efficient and secure k-NN search schemes based on matrix similarity to achieve efficient and secure query services in public cloud. In our basic scheme, we construct the traces of two diagonal multiplication matrices to denote the Euclidean distance of two data points, and perform secure k-NN search by comparing traces of corresponding similar matrices. In our enhanced scheme, we strengthen the security property by decomposing matrices based on our basic scheme. Security analysis shows that our schemes protect the data privacy and query privacy under attacking with different levels of background knowledge. Experimental evaluations show that both schemes are efficient in terms of computation complexity as well as computational cost.

Sharing personal data with other people or organizations over the web has become a common phenomena of our modern life. This type of sharing is usually managed by access control mechanisms that include access control model and policies. However, these models are designed from the organizational perspective and do not provide sufficient flexibility and control to the individuals. Therefore, individuals often cannot control sharing of their personal data based on their personal context. In addition, the existing context-aware access control models usually check contextual condition once at the beginning of the access and do not evaluate the context during an on-going access. Moreover, individuals do not have control to define how often they want to evaluate the context condition for an ongoing access. Wearable devices such as Fitbit and Apple Smart Watch have recently become increasingly popular. This has made it possible to gather an individual's real-time contextual information (e.g., location, blood-pressure etc.) which can be used to enforce continuous authorization to the individual's data resources. In this paper, we introduce a novel data sharing policy model for continuous authorization in subject-driven data sharing. A software prototype has been implemented employing a wearable device to demonstrate continuous authorization. Our continuous authorization framework provides more control to the individuals by enabling revocation of on-going access to shared data if the specified context condition becomes invalid.

Many enterprises and individuals prefer to outsource data to public cloud via various pricing approaches. One of the most widely-used approaches is the pay-as-you-go model, where the data owner hires public cloud to share data with data consumers, and only pays for the actually consumed services. To realize controllable and secure data sharing, ciphertext-policy attribute-based encryption (CP-ABE) is a suitable solution, which can provide fine-grained access control and encryption functionalities simultaneously. But there are some serious challenges when applying CP-ABE in pay-as-you-go. Firstly, the decryption cost in ABE is too heavy for data consumers. Secondly, ABE ciphertexts probably suffer distributed denial of services (DDoS) attacks, but there is no solution that can eliminate the security risk. At last, the data owner should audit resource consumption to guarantee the transparency of charge, while the existing method is inefficient. In this work, we propose a general construction named fully accountable ABE (FA-ABE), which simultaneously solves all the challenges by supporting all-sided accountability in the pay-as-you-go model. We formally define the security model and prove the security in the standard model. Also, we implement an instantiate construction with the self-developed library libabe. The experiment results indicate the efficiency and practicality of our construction.

Social media users generate tremendous amounts of data. To better serve users, it is required to share the user-related data among researchers, advertisers and application developers. Publishing such data would raise more concerns on user privacy. To encourage data sharing and mitigate user privacy concerns, a number of anonymization and de-anonymization algorithms have been developed to help protect privacy of social media users. In this work, we propose a new adversarial attack specialized for social media data.We further provide a principled way to assess effectiveness of anonymizing different aspects of social media data. Our work sheds light on new privacy risks in social media data due to innate heterogeneity of user-generated data which require striking balance between sharing user data and protecting user privacy.

The evolution of the microelectronics manufacturing industry is characterized by increased complexity, analysis, integration, distribution, data sharing and collaboration, all of which is enabled by the big data explosion. This evolution affords a number of opportunities in improved productivity and quality, and reduced cost, however it also brings with it a number of risks associated with maintaining security of data systems. The International Roadmap for Devices and System Factory Integration International Focus Team (IRDS FI IFT) determined that a security technology roadmap for the industry is needed to better understand the needs, challenges and potential solutions for security in the microelectronics industry and its supply chain. As a first step in providing this roadmap, the IFT conducted a security survey, soliciting input from users, suppliers and OEMs. Preliminary results indicate that data partitioning with IP protection is the number one topic of concern, with the need for industry-wide standards as the second most important topic. Further, the "fear" of security breach is considered to be a significant hindrance to Advanced Process Control efforts as well as use of cloud-based solutions. The IRDS FI IFT will endeavor to provide components of a security roadmap for the industry in the 2018 FI chapter, leveraging the output of the survey effort combined with follow-up discussions with users and consultations with experts.