Cryptocurrencies do not only allow for money transfers in the absence of a trusted third party but also enable the execution of distributed applications. Due to the rapid pace of development of cryptocurrencies, the foundations of such applications have not been rigorously studied. This is particularly problematic since in these applications, real money is at stake, and security breaches regularly cause severe financial losses.In this thesis, we present two systematic approaches to reliably verify the security of distributed blockchain applications based on formal foundations. To this end, we focus on the cryptocurrencies with the highest market capitalization, Bitcoin and Ethereum. In Ethereum, distributed applications are realized as smart contracts, reactive programs written in Ethereum’s expressive scripting language. In contrast, Bitcoin supports only a basic scripting language, and advanced applications are realized as peer-to-peer cryptographic protocols that resort to the execution of simple smart contracts in case of disputes among peers. As a result, the challenge in verifying distributed applications on the Ethereum blockchain lies in the study and abstraction of the semantics of Ethereum’s evolved scripting language, whereas Bitcoin, the study of distributed applications, requires a systematic analysis of the cryptographic protocols.In the thesis, we first formalize the formerly under-specified semantics of Ethereum’s native smart contract language EVM bytecode and implement the semantics in the proof assistant F*. In this context, we formally characterize relevant generic properties for smart contract security, which capture real-world attack scenarios.We then survey existing automated static analyzers for Ethereum smart contracts unveiling the weaknesses in the semantic foundations of these tools and the practical impact of these weaknesses on the analysis results. Based on these findings, we propose our own automatic static analysis tool for Ethereum smart contracts, which comes with a rigorous soundness proof while still showing competitive performance. In this course, we also propose a general framework for the modular and semantic-driven development of automatic static analyzers. Finally, we study the security of payment channel networks for Bitcoin. Payment channel networks are distributed protocols that allow for efficient and cheap payments between Bitcoin users and offer a promising solution to Bitcoin’s scalability problems. We unveil a security issue in Bitcoin’s existing payment channel network implementation and formally characterize the relevant security and privacy notions in this context. We further develop a cryptographic primitive for the construction of payment channel networks with formal security guarantees
In this work, we design and implement the first protocol for distributed generation of an RSA modulus that can support thousands of parties and offers security against active corruption of an arbitrary number of parties. In a nutshell, we first design a highly optimized protocol for this scale that is secure against passive corruptions, and then amplify its security to withstand active corruptions using lightweight succinct zero-knowledge proofs. Our protocol achieves security with "identifiable abort," where a corrupted party is identified whenever the protocol aborts, and supports public verifiability.Our protocol against passive corruptions extends the recent work of Chen et al. (CRYPTO 2020) that, in turn, is based on the blueprint introduced in the original work of Boneh-Franklin protocol (CRYPTO 1997, J. ACM, 2001). Specifically, we reduce the task of sampling a modulus to secure distributed multiplication, which we implement via an efficient threshold additively homomorphic encryption scheme based on the Ring-LWE assumption. This results in a protocol where the (amortized) per-party communication cost grows logarithmically in the number of parties. In order to minimize the work done by the parties, we employ a "publicly verifiable" coordinator that is connected to all parties and only performs computations on public data.We implemented both the passive and the active variants of our protocol and ran experiments using 2 to 4,000 parties. This is the first implementation of any MPC protocol that can scale to more than 1,000 parties. For generating a 2048-bit modulus among 1,000 parties, our passive protocol executed in under 6 minutes and the active variant ran in under 25 minutes.
A blockchain-based processing framework for sensitive data is proposed. The smart network comprises a blockchain module, an electronic contract (E-contract) layer node, and a Software-as-a-Service (SaaS) layer module. The underlying blockchain module provides technical support, such as virtual machines, consensus algorithms, transaction verification mechanisms, and accounting mechanisms. The E-contract layer module provides a distributed application service and uses the blockchain technology to support it. In addition, it runs the code of the sensitive data transaction system and the code created by the algorithm for encoding generation at the E-contract layer. The SaaS layer module offers a cloud-platform service that allows each party to easily engage in business collaboration via web portals or clients. The proposed smart system is used by each party get involved in the production of sensitive data. The final sensitive data are produced by the final data generator, and other modules involved in the process of data production are unaware of the final data. This approach prevents the leakage of sensitive data into the circulation.
Gaopeng Xie, Yuling Liu, Guojiang Xin, Qiuwei Yang
With the large-scale application of cloud storage, how to ensure cloud data integrity has become an important issue. Although many methods have been proposed, they still have their limitations. This paper improves some defects of the previous methods and proposes an efficient cloud data integrity verification scheme based on blockchain. In this paper, we proposed a lattice signature algorithm to resist quantum computing and introduced cuckoo filter to simplify the computational overhead of the user verification phase. Finally, the decentralized blockchain network is introduced to replace traditional centralized audit to publicize and authenticate the verification results, which improves the transparency and the security of this scheme. Security analysis shows that our scheme can resist malicious attacks and experimental results show that our scheme has high efficiency, especially in the user verification phase.
Blockchain rewriting with fine-grained access control allows a user to create a transaction associated with a set of attributes, while another user (or modifier) who possesses enough rewriting privileges from a trusted authority satisfying the attribute set can rewrite the transaction. However, it lacks accountability and is not designed for open blockchains that require no trust assumptions. In this work, we introduce accountable fine-grained blockchain rewriting in a permissionless setting. The property of accountability allows the modifier's identity and her rewriting privileges to be held accountable for the modified transactions in case of malicious rewriting (e.g., modify the registered content from good to bad). We first present a generic framework to secure blockchain rewriting in the permissionless setting. Second, we present an instantiation of our approach and show its practicality through evaluation analysis. Last, we demonstrate that our proof-of-concept implementation can be effectively integrated into open blockchains.
The act of maintaining educational records both online and on paper have become a norm. With the enforcement of lockdowns due to the Covid-19 pandemic, the education sector attempted to move their entire operations online. However with this move, various operations such as Verification of Documents, Approval of LORs have become harder to deal with in a legitimate manner. In this paper, we have compared various existing methods to deal with the problem at hand and proposed our system for the same.
Digital signatures and key exchange protocols are the two most important public key cryptographic primitives used in the electronic transmission of data. The goal of key exchange is to preserve the secrecy of the communication, while the goal of digital signatures is to guarantee the authenticity of the exchanged messages. Constructions of digital signature schemes based on classical mathematical assumptions appeared shortly following the invention of public key cryptography in the late 1970s. And just like with key exchange, the most efficient variants are based on number-theoretic problems that are believed to be (sub)-exponentially hard for classical machines, but are solved in polynomial time by Shor’s algorithm on a powerful-enough quantum computer. Also, like for key exchange, the most efficient constructions that we believe to be quantum safe are based on the presumed hardness of lattice problems over polynomial rings. One interesting difference between key exchange and digital signatures is that key exchange appears to inherently require that some mathematical problem be computationally hard. Digital signatures, on the other hand, can be generically constructed from any one-way function [1,2]. So even though they certainly fall into the category of public key primitives based on their usage, their existence requires much weaker assumptions. Additionally, the transformation from a one-way function to a digital signature is not too inefficient. For example, the total parameter size (public key + signature) of the SPHINCS+ scheme [3] is around 40 kB. While these sizes are larger, and signing times considerably longer, than those of signatures based on factoring or discrete log, it is still a usable scheme for many applications. And being only based on symmetric assumptions (e.g. one wayness and collision resistance of cryptographic hash functions), its security is very attractive. In order to be considered an interesting alternative to the above-mentioned signature, a scheme based on a mathematical assumption would need to have significant performance advantages. Schemes based on factoring and the discrete logarithm problem were significantly shorter and faster, and so the generic approach lay dormant for over four decades. The new quantum-safe schemes will need to have similar performance advantages if they are to be used in lieu of this safe approach. Below, we describe two techniques for constructing lattice-based digital signatures with output sizes being just a few kilobytes. On a very high level, lattice-based signature constructions follow the two known approaches for constructing classical signatures. In the first approach, the signer outputs a function f and an image y = f(x) as his public key and keeps x as his secret key. To sign a message μ, he gives a non-interactive zero-knowledge proof that he knows an x satisfying y = f(x), using the message μ to create the ‘challenge’ H(μ) for the proof (where H is a public function that maps μ to something ‘random looking’). If the function f is one way then the verifier should be convinced that the proof could have only been created by the entity who knows x. A classic example of this type of scheme is the Schnorr signature scheme [4] based on the hardness of the discrete logarithm problem. The second approach is to create a function f together with a trapdoor f−1, output f as the public key and keep f−1 as the secret key. A message μ is signed by using the secret trapdoor to create a pre-image x such that f(x) = H(μ). Again, if the function f is one way then only someone in possession of a trapdoor should be able to invert it. An example of such a construction based on a ‘factoring-like’ assumption is the RSA signature scheme [5]. The high-level ideas for lattice-based signatures follow the above blueprints, but the technical details are significantly more involved. The main reason for the complications is the different algebraic structure of the hard one-way function underlying lattice cryptography. While the domain of the function in discrete log and RSA-based one-way functions are groups, the domains in lattice-based signatures are sets that are not closed under any operation—in particular, they are elements in a group that have small norms. This crucial small norm requirement precludes us from using uniformly random masking as in Schnorr signatures or having a trapdoor for a bijective one-way function as in RSA signatures. These barriers have, nevertheless, been overcome and the resulting digital signatures are quite practical. In 2017, the US National Institute of Standards and Technology (NIST) began a ‘competition’ for a quantum-safe key exchange and digital signatures standard. At the time of this writing, this process is in the third round and there are two lattice-based signatures remaining—each following one of the above high-level designs. The CRYSTALS-Dilithium [6] scheme follows the Schnorr framework, but adds a crucial rejection-sampling step to keep the size of the coefficients small. The FALCON scheme [7] utilizes a randomized trapdoor sampling technique that uses a secret trapdoor for f−1 to produce random pre-images from a particular distribution. Because there is no longer a bijection, it is crucial to also have the property that the distribution of the outputted pre-images does not leak information about the trapdoor. Both schemes are relatively fast and their parameters (public key + signature size) are the shortest of all quantum-safe signature schemes. While both schemes are based on lattices, they have rather different characteristics. FALCON has very short parameters (see Table 1), but entails a rather complicated procedure for signature generation. In particular, it uses (an optimized version of) the GPV sampler [8], which requires floating-point arithmetic with approximately 64 bits of precision. Requiring such high precision means that subtle implementation errors may not get detected even with rigorous testing. Dilithium, on the other hand, has larger parameters but a very simple implementation where all the sampling in the signing is done in a power-of-2 range; it is thus much less prone to implementation errors. It is quite possible that in the future both schemes will be used for different applications. Approximate parameter sizes (in bytes) for the CRYSTALS-Dilithium and FALCON digital signature schemes at approximately 128-bit security levels. Approximate parameter sizes (in bytes) for the CRYSTALS-Dilithium and FALCON digital signature schemes at approximately 128-bit security levels. Conflict of interest statement. None declared.
Blockchain provides a creative approach to storing information, executing transactions, conducting tasks, and building trust. Some see Blockchain as a revolutionary technology for cryptography and cybersecurity, with applications ranging from cryptocurrency to healthcare, smart contracts, Internet of Things, smart grids governance, supply-chain etc. This research work would offer a detailed analysis of blockchain Security, Privacy and Trust. It further studies the applications of blockchain technology in the domain of education and involved challenges. Finally, it proposes a blockchain-based framework for secure and reliable student's record management.
Sidra Malik, Volkan Dedeoglu, Salil S. Kanhere, Raja Jurdak
Blockchain offers traceability and transparency to supply chain event data and hence can help overcome many challenges in supply chain management such as: data integrity, provenance and traceability. However, data privacy concerns such as the protection of trade secrets have hindered adoption of blockchain technology. Although consortium blockchains only allow authorised supply chain entities to read/write to the ledger, privacy preservation of trade secrets cannot be ascertained. In this work, we propose a privacy-preservation framework, PrivChain, to protect sensitive data on blockchain using zero knowledge proofs. PrivChain provides provenance and traceability without revealing any sensitive information to end-consumers or supply chain entities. Its novelty stems from: a) its ability to allow data owners to protect trade related information and instead provide proofs on the data, and b) an integrated incentive mechanism for entities providing valid proofs over provenance data. In particular, PrivChain uses Zero Knowledge Range Proofs (ZKRPs), an efficient variant of ZKPs, to provide origin information without disclosing the exact location of a supply chain product. Furthermore, the framework allows to compute proofs and commitments off-line, decoupling the computational overhead from blockchain. The proof verification process and incentive payment initiation are automated using blockchain transactions, smart contracts, and events. A proof of concept implementation on Hyperledger Fabric reveals a minimal overhead of using PrivChain for blockchain enabled supply chains.
Mamta, Brij B. Gupta, Kuan‐Ching Li, Victor C. M. Leung · 6 authors
The concept of sharing of personal health data over cloud storage in a healthcare-cyber physical system has become popular in recent times as it improves access quality. The privacy of health data can only be preserved by keeping it in an encrypted form, but it affects usability and flexibility in terms of effective search. Attribute-based searchable encryption (ABSE) has proven its worth by providing fine-grained searching capabilities in the shared cloud storage. However, it is not practical to apply this scheme to the devices with limited resources and storage capacity because a typical ABSE involves serious computations. In a healthcare cloud-based cyber-physical system (CCPS), the data is often collected by resource-constraint devices; therefore, here also, we cannot directly apply ABSE schemes. In the proposed work, the inherent computational cost of the ABSE scheme is managed by executing the computationally intensive tasks of a typical ABSE scheme on the blockchain network. Thus, it makes the proposed scheme suitable for online storage and retrieval of personal health data in a typical CCPS. With the assistance of blockchain technology, the proposed scheme offers two main benefits. First, it is free from a trusted authority, which makes it genuinely decentralized and free from a single point of failure. Second, it is computationally efficient because the computational load is now distributed among the consensus nodes in the blockchain network. Specifically, the task of initializing the system, which is considered the most computationally intensive, and the task of partial search token generation, which is considered as the most frequent operation, is now the responsibility of the consensus nodes. This eliminates the need of the trusted authority and reduces the burden of data users, respectively. Further, in comparison to existing decentralized fine-grained searchable encryption schemes, the proposed scheme has achieved a significant reduction in storage and computational cost for the secret key associated with users. It has been verified both theoretically and practically in the performance analysis section.
The Air Traffic Management (ATM) system is a network-centric intelligent information system that faces severe and complex challenges in the process of aviation information interaction. From the perspective of data security transmission in ATM networks, this paper proposes a blockchain-based trust model BlockTrust, combined with domestic cryptographic algorithms to establish a trust chain in the ATM air-space-ground integrated network. This paper uses such distributed ledger technology to design an architecture for ensuring the security of ATM information, ensuring the secure transmission and reliable sharing of aviation business data. In this paper, we will also take the submission and update process of flight plans as an example to discuss the possible benefits and risks of applying blockchain in this field.
To give charming networks of interests in computational activities, new structure is required for sharing ISR resources proficiently. The organization of blockchain innovation in wired exchange situations, such as computerized money frameworks, offers an energizing arrangement by making an approach to deal with a circulated shared record without requiring a solitary confided in the executives. Here, the chapter portrays how a blockchain-based framework can be moved to give an answer for dynamic resource distribution among global individuals, centering the advancement of an intelligently brought together resource executive framework by a stupendous approach agreeable relationship of assortment of worldwide frameworks. The Investment board (IM) pioneers have duties past examining the issues of the day—they ought to likewise arrange for what&s;s to come. Blockchain is one essential innovation that should be requested for IM authority consideration for two reasons. To begin with, this innovation has the ability to move and change resource the board firm worth chains. Furthermore, it is in first phases of advancement, motion different positive conditions. The appropriation of blockchain for three different sorts of advantages in an alliance setting, displaying how blockchain can give a reasonable explanation to apportioning resources in those situations. The defect in the present use of square chain should be improved for the innovation to arrange progressively successful decentralized strategic edge condition. Blockchain and brilliant agreements can oversee raising and calling capital, in this manner smoothing the procedure and expelling a portion of the hazard. Keen contracts and blockchain innovation have the ability to give an optionally computerized procedure, with an individual on the up and up as wanted.
In the post-cloud era, edge computing is a new computing paradigm with data processed at the edge of the network, which can process the data close to the end-user in real time and offload the cloud task intelligently. Meanwhile, the decentralization, tamper-proof and anonymity of blockchain technology can provide a new trusted computing environment for edge computing. However, it does raise considerable concerns of security, privacy, fault-tolerance and so on. For example, identity authentication and access control rely on third parties, heterogeneous devices and different vendors in IoT, leading to security and privacy risks, etc. How to combine the advantages of the two has become the highlight of academic research, especially the issue of secure resource management. Comprehensive security and privacy involve all aspects of platform, data, application and access control. In. this paper, the architecture and behavior of an Access Management System (AMS) in a proof of concept (PoC) prototype are proposed with a Color Petri Net (CPN) model. The two domains of blockchain and edge computing are organically connected by interfaces and interactions. The simulation of operation, activity and role association proves the feasibility and effectiveness of the AMS. The instances of platform business access control, data access control, database services, IOT hub service are run on Advantech WISE-PaaS through User Account and Authentication (UAA). Finally, fine-grained and distributed access control can be realized with the help of a blockchain attribute. Namely, smart contracts are used to register, broadcast, and revoke access authorization, as well as to create specific transactions to define access control policies.
The increasing adoption of multi-cloud computing has created new opportunities for improving resource utilization, service reliability, and reducing dependence on a single cloud provider. However, the distributed nature of multi-cloud infrastructures introduces significant challenges in maintaining data security, privacy, and continuous service availability. This study presents a dynamic security framework designed for multi-cloud environments that integrates adaptive monitoring with a multi-layer encryption mechanism. The proposed approach intelligently selects suitable encryption techniques based on data sensitivity, file size, and available computing resources to achieve an optimal balance between security and performance. The framework Dynamic Resource Management Algorithm(DRMA) for secure key establishment, efficient symmetric encryption for protecting data, and zero-knowledge proof-based authentication to ensure secure user verification without revealing sensitive information. A comprehensive performance evaluation was conducted by comparing the proposed model with conventional RSA-based security approaches. Experimental results demonstrate improved computational efficiency, reduced encryption overhead, enhanced scalability, and stronger protection against unauthorized access. Furthermore, the framework provides resilience against both conventional cyberattacks and emerging quantum computing threats while maintaining efficient resource utilization. These findings indicate that the proposed solution offers a practical and secure approach for protecting data and improving the reliability of modern multi-cloud environments.
Consensus protocols are used for the distributed management of large databases in an environment without trust among participants. The choice of a specific protocol depends on the purpose and characteristics of the system itself. The subjects of the paper are consensus protocols in permissioned blockchains. The objective of this paper is to identify functional advantages and disadvantages of observed protocol. The analysis covers a total of six consensus protocols for permissioned blockchains. The following characteristics were compared: security, trust among participants, throughput and scalability. The results show that no protocol shows absolute dominance in all aspects of the comparison. Paxos and Raft are intended for systems in which there is no suspicion of unreliable users, but only the problem of a temporary shutdown. Practical Byzantine Fault Tolerance is intended for systems with a small number of nodes. Federated Byzantine Fault Tolerance shows better scalability and is more suitable for large systems, but can withstand a smaller number of malicious nodes. Proof-of-authority can withstand the largest number of malicious nodes without interfering with the functioning of the system. When choosing a consensus protocol for a blockchain application, one should take into account priority characteristics.
In recent years we have witnessed a dramatic increase in the applications of blockchain and smart contracts in a variety of contexts, including supply-chain, decentralized finance, and international money transfers. However, a critical stumbling block to their further adoption is smart contract security (or more precisely, the lack thereof). Smart contracts, once deployed on a blockchain, are immutable. Hence, unlike traditional software systems, smart contracts are particularly vulnerable to latent security issues. It is therefore imperative that security analysis tools be developed that help improve smart contract security if they are to have continued adoption and impact. A particularly widespread class of security vulnerabilities that afflicts Ethereum smart contracts is the gas-based denial of service (DoS). Briefly, these vulnerabilities generally present in contracts containing unbounded loops. \n \nTo address the described problem, we present Gas Gauge, a tool aimed at detecting gas-based DoS vulnerabilities in Ethereum smart contracts. Gas Gauge consists of three major components: the Detection Phase, Identification Phase, and Correction Phase. First, we describe a highly accurate static analysis approach that finds all the loops in a smart contract (the Detection Phase). Then, a set of inputs that causes the contract to run out of gas is generated using a fuzzing approach. The last component uses static analysis and run-time verification to predict the maximum loop bounds consistent with allowable gas usage automatically. This component uses a binary search approach and an independent parallel processing design to speed up the process. Each part of the tool can be used separately for different purposes or all together to detect, identify and help repair the contracts vulnerable to out-of-gas behaviors. \n \nGas Gauge was tested on 2,000 real-world solidity smart contracts. The results were compared to seven state-of-the-art tools, and it was empirically demonstrated that Gas Gauge is highly effective and useful.
In the current epoch of smart homes and cities, personal data such as patients' names, diseases and addresses are often violated. This is frequently associated with the safety of the electronic health records (EHRs) of patients. EHRs have numerous benefits worldwide, but at present, EHR information is subject to considerable security and privacy issues. This paper proposes a way to provide a secure solution to these issues. Previous sophisticated techniques dealing with the protection of EHRs usually make data inaccessible to patients. These techniques struggle to balance data confidentiality, patient demand and constant interaction with provider data. Blockchain technology solves the above problems since it distributes information in a transactional and decentralized manner. The usage of blockchain technology could help the health sector to balance the accessibility and privacy of EHRs. This paper proposes a blockchain security framework (BSF) to effectively and securely store and keep EHRs. It presents a safe and proficient means of acquiring medical information for doctors, patients and insurance agents while protecting the patient's data. This work aims to examine how our proposed framework meets the security needs of doctors, patients and third parties and how the structure addresses safety and confidentiality concerns in the healthcare sector. Simulation outcomes show that this framework efficiently protects EHR data.
Ahmad Ali, Abid Khan, Mansoor Ahmed, Gwanggil Jeon
Abstract A computing environment requires a robust and comprehensive process to track and document user activities to uphold confidence in the system. Audit logs are used for this purpose to monitor the actions of administrators and users. However, these logs are vulnerable to multidimensional attacks, including modification of logs, erasability of logs, and privacy of the user. Since administrators have unprecedented access to these logs, they can modify, delete, and even destroy them. Securing these logs against malicious activities is the prime requirement of audit log management. Existing schemes have several limitations, including immutability, computational expensiveness, missing semantics, and are not verifiable. Various schemes have been proposed for this purpose, but a standard method is required to structure heterogeneous logs and their security semantically. To cope with these limitations, in this paper, we propose a Log Management System using blockchain. The proposed system will ensure audit logs' security, which will eventually strengthen users' trust in the computing environment and make it unbreachable even by the administrators. It has been evinced that our model performed better in terms of performance and features already mentioned when compared with existing schemes.
Cloud servers offer data owners the opportunityto upload and store encrypted data that several data users can access. However, after outsourcing data to the cloud, data owners have limited control of their data, and external systems are incorporated to manage it. Several research-based solutions use encryption techniques to prevent unauthorized access to the data but ignore the challenge of maintaining the trace of valid changes applied to the data. Provenance data can be used to ascertain the integrity of data and, therefore, should be immutable and secured from adversaries since it contains private information. This article proposes an efficient way of securing access logs by leveraging blockchain. A generic framework is designed, tested, and evaluated, with results showing our model can effectively enhance the security of provenance data. This work considers two categories of data users and account for the distinct roles and permitted actions on the outsourced data. In summary, this work ensures that the data is trustworthy, and verification and management of the outsourced data are assured. Experimental results illustrate the efficiency and scalability of our solution.
Data security in the cloud has become a dominant topic being discussed in recent times as the security of data in the cloud has been focused on by several researchers. However, the data security was enforced at the attribute level, the adversaries are capable of learning the method of data encryption even there are access restrictions are enforced at an attribute level. To challenge the adversaries with more sophisticated security measures, an efficient real-time service-centric feature sensitivity analysis (RSFSA) model is proposed in this paper. The RSFSA model analyses the sensitivity of different features being accessed by any service and at multiple levels. At each level, the method checks the set of features being accessed and the number of features the user has access grant to compute the FLAG value for the user according to the profile given. Based on the value of FLAG, the user has been granted or denied service access. On the other side, the method maintains different encryption schemes and keys for each level of features. As the features are organized in multiple levels, the method maintains a set of schemes and keys for each level dedicative. Based on the service level and data, the method selects an encryption scheme and key to perform data encryption. According to that, the service access data has been encrypted at the attribute level with a specific scheme and key. Data encrypted has been uploaded to the blockchain and the method modifies the reference part of the chain to connect only the blocks to which the user has access. The chain given to the user would do not contain any reference from a specific block to which the user has no access. The proposed method improves the performance of data security and access restriction greatly.
Abstract The persevering pursuit of security has proved historically limiting the implementation of significant design improvements for Electronic Health Records (EHR). Such a vital requirement for these kinds of technical development is revamped now. This is because the patients are motivated by personalization and data science to participate in the health information sharing. The implementation of cloud computing has already shown substantial benefits for both clinical organizations and patients in managing electronic health records. The prime security issue of cloud-based electronic health records is that the patient is physically unable to own a medical record whereas a clinical organization can maintain one for them. The latter may collude with centralized cloud servers. So, there is a vulnerability of such records being tampered with in order to hide the medical malpractices. So, maintaining data integrity and data privacy becomes a significant challenge when deploying cloud computing. Therefore, in this paper, a consortium blockchain-based cloud-stored electronic health record is proposed which provides data integrity, data privacy, storage scalability, and fine-grained access control. Each process in outsourcing electronic health records to the cloud is incorporated as a transaction in a consortium ethereum blockchain through smart contracts. Through smart contracts, an attribute-based contract key is generated for the users that can decrypt the encrypted data stored in the cloud. The attribute-based contract key allows only users who are authorized to access the information ensuring data privacy and fine-grained access control. Moreover, the proposed scheme is proved to provide tamper-proof although the medical records are controlled by a group of clinical organizations.
In recent years, we have witnessed the evolutionary development of a new breed of distributed systems. Systems of this type share a number of characteristics – highly decentralized, of Internet-grade scalability, and autonomous within their administrative domains. Most importantly, they are expected to operate collaboratively across both known and unknown domains. Prime examples include peer-to-peer applications and open web services. Typically, authorization in distributed systems is identity-based, e.g. access control lists. However, approaches based on predefined identities are unsuitable for the new breed of distributed systems because of the need to deal with unknown users, i.e. strangers, and the need to manage a potentially large number of users and/or resources. Furthermore, effective administration and management of authorization in such systems requires: (1) natural mapping of organizational policies into security policies; (2) managing collaboration of independently administered domains/organizations; (3) decentralization of security policies and policy enforcement. This thesis describes Fidelis, a trust management framework designed to address the authorization needs for the next-generation distributed systems. A trust management system is a term coined to refer to a unified framework for the specification of security policies, the representation of credentials, and the evaluation and enforcement of policy compliances. Based on the concept of trust conveyance and a generic abstraction for trusted information as trust statements, Fidelis provides a generic platform for building secure, trust-aware distributed applications. At the heart of the Fidelis framework is a language for the specification of security policies, the Fidelis Policy Language (FPL), and the inference model for evaluating policies expressed in FPL. With the policy language and its inference model, Fidelis is able to model recommendation-style policies and policies with arbitrarily complex chains of trust propagation. Web services have rapidly been gaining significance both in industry and research as a ubiquitous, next-generation middleware platform. The second half of the thesis describes the design and implementation of the Fidelis framework for the standard web service platform. The goal of this work is twofold: first, to demonstrate the practical feasibility of Fidelis, and second, to investigate the use of a policy-driven trust management framework for Internet-scale open systems. An important requirement in such systems is trust negotiation that allows unfamiliar principals to establish mutual trust and interact with confidence. Addressing this requirement, a trust negotiation framework built on top of Fidelis is developed. This thesis examines the application of Fidelis in three distinctive domains: implementing generic role-based access control, trust management in the World Wide Web, and an electronic marketplace comprising unfamiliar and untrusted but collaborative organizations.