Alexandre Pinheiro, Edna Dias Canedo, Rafael T. de Sousa, Robson de Oliveira Albuquerque
The adoption of cloud computing solutions is an established reality in government agencies and in small, medium, and large companies due to procurement easiness and the variety of available services, as well as its low cost compared to the acquisition and management of own infrastructures. Among the most used services is cloud file storage, and the security of this storage has been an essential subject of recent research, particularly customer data integrity. Thus, this article proposes a solution for the monitoring of the integrity of files stored in the cloud, based on the use of smart contracts in Blockchain Networks, symmetric encryption, and computational trust. The proposed solution consists of a protocol that provides confidentiality, decentralization, audit availability, and the secure sharing of file integrity monitoring results, without overloading the services involved, as well as an unabridged reference implementation which was used to validate the proposal. The results obtained during the validation tests have shown that the solution is feasible and faultless in detecting corrupted files. These tests also confirmed that the sharing of integrity monitoring results, coupled with the application of computational trust techniques, significantly increased the efficiency of the proposed solution.
Mohammad Madine, Ammar Battah, Ibrar Yaqoob, Khaled Salah · 8 authors
Personal health records (PHRs) are valuable assets to individuals because they enable them to integrate and manage their medical data. A PHR is an electronic application through which patients can manage their health information. Giving patients control over their medical data offers an advantageous realignment of the doctor-patient dynamic. However, today's PHR management systems fall short of giving reliable, traceable, trustful, and secure patients control over their medical data, which poses serious threats to their authenticity and accuracy. Moreover, most of the current approaches and systems leveraged for managing PHR are centralized that not only make medical data sharing difficult but also poses a risk of single point of failure problem. In this paper, we propose Ethereum blockchain-based smart contracts to give patients control over their data in a manner that is decentralized, immutable, transparent, traceable, trustful, and secure. The proposed system employs decentralized storage of interplanetary file systems (IPFS), proxy re-encryption, and trusted reputation-based oracles to securely fetch, store, and share patients' medical data. We present algorithms along with their full implementation details. We evaluate the proposed smart contracts using two important performance metrics, such as cost and correctness. Furthermore, we provide security analysis and discuss the generalization aspects of our solution. We outline the limitations of the proposed approach. We make the smart contract source code publicly available on Github.
Distributed Ledger Technologies (DLTs), like Blockchain, are characterized by features such as transparency, traceability, and security by design. These features make the adoption of Blockchain attractive to enhance information security, privacy, and trustworthiness in very different contexts. This paper provides a comprehensive survey and aims at analyzing and assessing the use of Blockchain in the context of Distributed Trust and Reputation Management Systems (DTRMS). The analysis includes academic research as well as initiatives undertaken in the business domain. The paper defines two taxonomies for both Blockchain and DTRMS and applies a Formal Concept Analysis. Such an approach allowed us to identify the most recurrent and stable features in the current scientific landscape and several important implications among the two taxonomies. The results of the analysis have revealed significant trends and emerging practices in the current implementations that have been distilled into recommendations to guide Blockchain's adoption in DTRMS systems.
The development of a robust, transparent and interoperable E-healthcare infrastructure has been a difficult task due to many regulations and legislatures like HIPAA (Health Insurance Portability and Accountability Act) and GDPR (General Data Protection Regulation). Healthcare service providers prefer to store data about their patients in locked up silos, behind often inadequate layers of security and firewalls. Such an approach results in data breaches and limits the ability to get a holistic view of the medical history of a patient. The obscure cost of treatment is another issue brought to attention recently in media. In this paper, we have proposed a national blockchain framework for managing patients' Electronic Health Records (EHRs) access control and funds in the context of India's National healthcare scheme. We introduce a transparent insurance claim process for healthcare providers and an auditable trail of EHR access using smart contracts. We use a smart card approach allowing beneficiaries to authenticate their identity using zero-knowledge proofs and delegate access to service the providers via proxy re-encryption.
Dimitris Karakostas, Aggelos Kiayias, Mario Larangeira
Blockchain protocols based on Proof-of-Stake (PoS) depend—by nature—on the active participation of stakeholders. If users are offline and abstain from the PoS consensus mechanism, the system’s security is at risk, so it is imperative to explore ways to both maximize the level of participation and minimize the effects of non-participation. One such option is stake representation, such that users can delegate their participation rights and, in the process, form “stake pools”. The core idea is that stake pool operators always participate on behalf of regular users, while the users retain the ownership of their assets. Our work provides a formal PoS wallet construction that enables delegation and stake pool formation. While investigating the construction of addresses in this setting, we distil and explore address malleability, a security property that captures the ability of an attacker to manipulate the delegation information associated with an address. Our analysis consists of identifying multiple levels of malleability, which are taken into account in our paper’s core result. We then introduce the first ideal functionality of a PoS wallet’s core which captures the PoS wallet’s capabilities and is realized as a secure protocol based on standard cryptographic primitives. Finally, consider the wallet core in conjunction with a PoS ledger and investigate how delegation and stake pools affect a PoS system’s security.
Proof-of-stake blockchain protocols are becoming one of the most promising alternatives to the energy-consuming proof-of-work protocols. However, one particularly critical threat in the PoS setting is the well-known long-range attacks caused by secret key leakage (LRSL attack). Specifically, an adversary can attempt to control/compromise accounts possessing substantial stake at some past moment such that double-spend or erase past transactions, violating the fundamental persistence property of blockchain. Puncturable signatures provide a satisfying solution to construct practical proof-of-stake blockchain resilient to LRSL attack, despite of the fact that existent constructions are not efficient enough for practical deployments. In this paper, we provide an in-depth study of puncturable signatures and explore its applications in the proof-of-stake blockchain. We formalize a security model that allows the adversary for adaptive signing and puncturing queries, and show a construction with efficient puncturing operations based on the Bloom filter data structure and strong Diffie-Hellman assumption. The puncturing functionality we desire is for a particular part of message, like prefix, instead of the whole message. Furthermore, we use puncturable signatures to construct practical proof-of-stake blockchain protocols that are resilient to LRSL attack, while previously the forward-secure signature is used to immunize this attack. We implement our scheme and provide experimental results showing that in comparison with the forward-secure signature, our construction performs substantially better on signature size, signing and verification efficiency, significantly on key update efficiency.
Kentaroh Toyoda, Koji Machi, Yutaka Ohtake, Allan N. Zhang
Private Ethereum blockchain-based systems are demanded in many industry sectors. However, the throughput performance of these systems does not meet their expectations. Many researchers have analyzed the performance of private blockchains, but their studies have failed to analyze root causes. In this paper, we perform a deep function-level bottleneck analysis for the private Ethereum blockchain. As the Ethereum client application is developed with golang, we leverage pprof, which is a resource-profiling tool for golang, and custom golang functions to measure the time taken by functions. To easily configure parameters and conduct our test, we code a shell script that automates the building process of a private Ethereum blockchain with docker containers. We conducted a series of experiments and identified the bottleneck function that is called every time a transaction arrives at an Ethereum node. In addition, we also found that the multi-threading is not well utilized, meaning that there is much room for improvement.
Eman M. Abou-Nassar, Abdullah M. Iliyasu, Passent Elkafrawy, Oh-Young Song · 6 authors
Today, internet and device ubiquity are paramount in individual, formal and societal considerations. Next generation communication technologies, such as Blockchains (BC), Internet of Things (IoT), cloud computing, etc. offer limitless capabilities for different applications and scenarios including industries, cities, healthcare systems, etc. Sustainable integration of healthcare nodes (i.e. devices, users, providers, etc.) resulting in healthcare IoT (or simply IoHT) provides a platform for efficient service delivery for the benefit of care givers (doctors, nurses, etc.) and patients. Whereas confidentiality, accessibility and reliability of medical data are accorded high premium in IoHT, semantic gaps and lack of appropriate assets or properties remain impediments to reliable information exchange in federated trust management frameworks. Consequently, We propose a Blockchain Decentralised Interoperable Trust framework (DIT) for IoT zones where a smart contract guarantees authentication of budgets and Indirect Trust Inference System (ITIS) reduces semantic gaps and enhances trustworthy factor (TF) estimation via the network nodes and edges. Our DIT IoHT makes use of a private Blockchain ripple chain to establish trustworthy communication by validating nodes based on their inter-operable structure so that controlled communication required to solve fusion and integration issues are facilitated via different zones of the IoHT infrastructure. Further, C# implementation using Ethereum and ripple Blockchain are introduced as frameworks to associate and aggregate requests over trusted zones.
Hamda Al Breiki, Muhammad Habib ur Rehman, Khaled Salah, Davor Svetinović
The essence of blockchain smart contracts lies in the execution of business logic code in a decentralized architecture in which the execution outcomes are trusted and agreed upon by all the executing nodes. Despite the decentralized and trustless architectures of the blockchain systems, smart contracts on their own cannot access data from the external world. Instead, smart contracts interact with off-chain external data sources, called oracles, whose primary job is to collect and provide data feeds and input to smart contracts. However, there is always risk of oracles providing corrupt, malicious, or inaccurate data. In this paper, we analyze and present the notion of trust in the oracles used in blockchain ecosystems. We analyze and compare trust-enabling features of the leading blockchain oracle approaches, techniques, and platforms. Moreover, we discuss open research challenges that should be addressed to ensure secure and trustworthy blockchain oracles.
Blockchain technology has been deemed to be an ideal choice for strengthening existing computing systems in varied manners. As one of the network-enabled technologies, cloud computing has been broadly adopted in the industry through numerous cloud service models. Fusing blockchain technology with existing cloud systems has a great potential in both functionality/performance enhancement and security/privacy improvement. The question remains on how blockchain technology inserts into current deployed cloud solutions and enables the reengineering of cloud datacenter. This survey addresses this issue and investigates recent efforts in the technical fusion of blockchain and clouds. Three technical dimensions roughly are covered in this work. First, we concern the service model and review an emerging cloud-relevant blockchain service model, Blockchain-as-a-Service (BaaS); second, security is considered a key technical dimension in this work and both access control and searchable encryption schemes are assessed; finally, we examine the performance of cloud datacenter with supports/participance of blockchain from hardware and software perspectives. Main findings of this survey will be theoretical supports for future reference of blockchain-enabled reengineering of cloud datacenter.
Shoba, Prof. M. Shanmugam, Venkatapur, Dr. Rekha B
Blockchain has become one of the most pioneeringtechnologies, with the rise of Bitcoin, blockchain which is the core technology of Bitcoin has received increasing attention. There are multiple signature scheme based on digital signature schemes that supports making signatures on many different messages generated by many different users, the size of the signature could be shortened by compressing multiple signatures into a single signature. Based on the blockchain architecture and existing Merkle tree based signature schemes, In this paper, an analysis of how to enhance the signature schemes to secure the transactions on blockchain based on extensible post-quantum (PQ) resistant digital signature scheme best suited to blockchain and distributed ledger technologies is proposed.
Tadas Limba, Andrius Stankevičius, Antanas Andrulevičius
Cryptocurrency market is developing fast during the past few years. Cryptocurrency now is available as a form of payment for retail goods, as an instrument for a wholesale international transaction a mean of exchange for whatever goods and is available through ATM's. Moreover, it is developing as a possibility for fundraising a) as a private debt b) as seed capital. Companies like Facebook are discussing launching own cryptocurrency. Bank UBS is developing its blockchain based virtual currency as well. However, scientist agrees that cryptocurrency has an important impact to national security. It became a relevant instrument for illegal good transactions, a mean of exchange in the darknet and an instrument for money laundering or infrastructure for new kind of money-laundering practices (for example-"Smurfing" phenomena (EU Observer, 2019)) European Union is launching AML and KYC procedures for the cryptocurrency market. Would it be efficient? Why are we implementing KYC and AML procedures for cryptocurrency? Is it able to minimize risks?
Cloud computing is an information technology that enables different users to access a shared pool of configurable system resources and different services without physically acquiring them. Most industries nowadays such as banking, healthcare and education are migrating to the cloud due to its efficiency of services especially when it comes to data security and integrity. Cloud platforms encounter numerous challenges such as Data deduplication, Data Transmission, Data Integrity, VM Security, Data Availability, Bandwidth usage… etc. In this paper we have adopted the Blockchain technology - which is a relatively new technology - that emerged for the first time as the cryptocurrency Bitcoin and proved its efficiency in securing data and assuring data integrity. It is mostly a distributed public ledger that holds transactions data in case of Bitcoin. In our work blockchains are adopted in a different way than its regular use in bitcoin. Three of the major challenges in Cloud Computing and Cloud services are Data Deduplication, Storage and Bandwidth usage are discussed in this paper.
Proof of retrievability is a cryptographic tool which interacts between the data user and the server, and the server proves to the data user the integrity of data which he will download. It is a crucial problem in outsourcing storage such as cloud computing. In this paper, a novel scheme called the zero knowledge proof of retrievability is proposed, which combines proof of retrievability and zero knowledge proof. It has lower computation and communication complexity and higher security than the previous schemes.
V. Brindha Devi, R. Skanda Gurunathan, N. Keerthivasan
The rapid growth in the population has lead to generation of large amount of data from each individual. Each and every individual holds several physically signed documents. Currently, the documents, certificates, and contracts are all printed in papers and manually signed. It is difficult for other party say a recruiter, or a government official or any other custom officer to verify the validity of the certificates and other documents of the individual. It consumes a tremendous amount of time for validating and verifying such documents manually. Thus we propose a system to develop a Decentralized application (DApp) for implementing a Blockchain[1] to store and verify the documents. By the nature of blockchain, the documents are securely stored with high integrity, and no further modifications can be done to the blocks in the chain which in turn reduces the creation of forged documents. Also using Distributed Ledger technology(DLT)[5] and IPFS the data is decentralised so that it is readily available with integrity. Also, using MultiSig[3] concepts, the system is more secured by two step authentication. Thus, blockchain creates trust and DLT provides integrity ease of access. And with use of IPFS the DApp is decentralized4]
In industrial automation, numerous devices are interconnected in smart factories for further monitor and control. Various infrastructure devices in industrial automation are usually used for control instruction distribution, data collection, and collaboration of the industrial applications. Recent security threats on industrial automation are more frequent and the industrial control systems lack trust mechanism. Blockchain has been introduced due to its decentralization and security promise, but the election results in the original designs could be biased without collaboration trust, which leads the blockchain-based industry applications invalid. In addition, in existing solutions, neither supernodes nor normal nodes in blockchain can transfer their control authorities for disaster backup. To address the aforementioned challenges, this article proposes a collaborative trust based unbiased control transfer mechanism (CTM), which realizes a dynamic assignment of industrial control. First, a collaborative trust based delegated proof of stake consensus is proposed for determining the authorities of control dynamically and unbiasedly, by designing a lightweight trust propagation protocol. Second, a CTM for checking, alarming, and restarting CTM is devised for the disaster backup. The simulation results demonstrate the CTM, which is feasible and effective for industrial automation security.
Huiqun Wu, Yujuan Shang, Lei Wang, Lili Shi · 6 authors
To design a blockchain-based framework for the cross-enterprise document sharing (XDS) and integration of electronic health records (EHR). In compliance with the integrated healthcare enterprise (IHE) profile, the XDS of EHRs were sent to the EHR cloud repository from each registered healthcare providers or by users themselves, and their link was shared and incorporated into a blockchain framework by using the same identifier for the same patient. In our proposed system, we used the link of XDS repository to hash the XDS EHR with SHA-256, which is a string of 64 HEX characters (32 bytes), and embossed it with a timestamp to indicate when the document was created or recorded in the blockchain. Then, the interested stakeholders verified the authenticity of the XDS EHR document by taking the hash of the document and matching it with the hash value stored in the Blockchain. A decentralized, non-tamperable, and encrypted storage framework was prototyped to enable the integration and sharing of XDS EHR. In this prototype, patient-centric EHR of different healthcare providers could be accessed in the blockchain dashboard of health records. The proposed blockchain framework provides a solution for the longitudinal storage of patient EHR and for sharing it in a secure and patient-centric way.