Victor Osmov, Atadjan Kurbanniyazov, Rasheed Hussain, Alma Oracevic · 6 authors
The past few years have witnessed unprecedented advancements in the Distributed Ledger Technology (DLT) and blockchain - a form of DLT. DLT has clearly expanded the applications landscape in various sectors of our lives ranging from banking to business, finance, industry, education, and so on. On the other hand, security plays a crucial part in the successful realization of such applications and services. To this end, cryptography is the primary mean to protect the applications, networks, infrastructure, and services from cyber-threats. However, the existing Public Key Infrastructure (PKI) is based on central Certificate Authority (CA) that can become a bottleneck and may affect the efficiency of the cryptographic protocols because of the overhead incurred by the verification of cryptographic signatures and certificates. Recently, blockchain has also been leveraged to aid PKI without the need for a central authority. In this spirit, in this paper, we develop and implement a blockchain-based PKI using open-source Hyperledger Sawtooth. The proposed blockchain-based approach helps to address the problems of the existing PKI such as compromised and misbehaving CAs.
Kapil Singi, Jagadeesh Chandra Bose R P, Sanjay Podder, Adam P. Burden
Modern software delivery happens in a geographically distributed environment and resembles like a supply chain - consists of various participants, involves various phases, needs adherence to multiple regulations and needs to maintain artifacts' integrity throughout the delivery phases. This shift in software development brings along with it several challenges ranging from communication of information/knowledge, coordination and control of teams, activities adhering to goals and policies and artifacts adhering to quality, visibility, and management. With the dispersion of centralized control over software delivery to autonomous delivery organizations, the variety of processes and tools used turns transparency into opacity as autonomous teams use different software processes, tools, and metrics, leading to issues like ineffective compliance monitoring, friction prone coordination, and lack of provenance, and thereby trust. In this paper, we present a delivery governance framework based on distributed ledger technology that uses a notion of `software telemetry' to record data from disparate delivery partners and enables compliance monitoring and adherence, provenance and traceability, transparency, and thereby trust.
Many critical applications are designed on the distributed structure using the blockchain technology to ensure the availability, immutability, and security. However, these applications are facing the storage problem owing to the data volume growth of transaction. The number of transactions and its size in a block is growing in the blockchain day by day because of the feature of immutability and append-only. The growing nature of transactions in a block is not only making the problem for storage but also in access to the block transactions. In this paper, we propose an IPFS based blockchain storage model to solve the storage problem of transaction in a block along with access of transaction of a particular block. In the propose storage model, the miners stores transaction on IPFS distributed file system storage and get the returned IPFS hash of transaction into the block of the blockchain. The feature of the IPFS network and its resultant hash reduce the size of transactions in a block. To secure access of transaction for a particular block content-addressed (IPFS hash) storage technique has been proposed. We have applied this scheme on a transaction which includes image storage on IPFS and hash storage into the blockchain. In this paper, we have also proposed the content-addressed technique in contrast to the location addressed for the access of transaction. To implement the framework we have used anaconda python, python flask, and IPFS.
This paper presents an extensible non-fungible token (NFT) model for supporting NFTs in Hyperledger Fabric (Fabric) with reference to ERC-721 defined as Ethereum standard NFT and Cosmos NFT. In this model, we defined the standard structure and interface for all Fabric NFTs. This model also supports the extensible structure and interface that accommodates different types of NFTs. To demonstrate how to take advantage of this model, we applied extensible NFTs such as document and signature tokens to a decentralized signature service.
ABSTRACT In this research, we often refer to Nakamoto's (2008) seminal paper, “Bitcoin: A Peer-to-Peer Electronic Cash System,” to consider his proposed abstracted characteristics and how auditors could look at companies' transactions interfacing to a private/semi-private blockchain with Nakamoto's general characteristics and address the related audit domain for such transactions. We then take these design requirements for auditors and, using design science research (DSR), we consider the transaction processing and contracting contexts that match those requirements in permissioned blockchains.The blockchains discussed in this paper would typically be business-to-business or business-to-consumer, private or semi-private, and residing in either a private, semi-private, or public cloud. Those blockchains will each have their own design and operational procedures, including validation procedures (the miners). We consider the audit issues of data reliability, data security, and transaction transparency in accounting transactions that lend themselves to a permissioned blockchain as well as other contextual issues.
Atomic Swap enables two parties to atomically exchange their own cryptocurrencies without trusted third parties. This paper provides the first quantitative analysis on the fairness of the Atomic Swap protocol, and proposes the first fair Atomic Swap protocol with implementations.
Summary The risk of sharing data in cloud computing has gathered increasing attention. After the owner of some confidential data outsources the data to cloud storage services and shares it with others, the data owner lost the control to the data to a large extent. To achieve data sharing while keeping data confidentiality, attribute‐based encryption (ABE) can be employed by cloud storage services. However, ABE can only guarantee that outsourced data on the cloud is decrypted by attribute‐satisfying users but cannot restrict data from being accessed by dishonest users whose attributes also satisfy the access‐control policy. It is impossible for the data owner to control the shared data after it has been decrypted by dishonest users, especially when a set of attribute‐satisfying dishonest users may collude. To address this concern, we propose a traceable data sharing scheme called TraceChain. In TraceChain, data is encrypted over a new CP‐ABE scheme called E‐CP‐ABE. Furthermore, the system parameters for generating the private key in E‐CP‐ABE are uploaded to the private blockchain and transactions are performed on the chain. The data owner can obtain the identity of users by monitoring system parameters simultaneously and control data sharing on the blockchain. To prove the security of our scheme, the security analysis is given in this paper. Meanwhile, experimental results also show that our system is viable and efficient.
Patrick McCorry, Surya Bakshi, Iddo Bentov, Sarah Meiklejohn · 5 authors
State channels are a leading approach for improving the scalability of blockchains and cryptocurrencies. They allow a group of distrustful parties to optimistically execute an application-defined program amongst themselves, while the blockchain serves as a backstop in case of a dispute or abort. This effectively bypasses the congestion, fees and performance constraints of the underlying blockchain in the typical case. However, state channels introduce a new and undesirable assumption that a party must remain online and synchronised with the blockchain at all times to defend against execution fork attacks. An execution fork can revert a state channel's history, potentially causing financial damage to a party that is innocent except for having crashed. To provide security even to parties that may go offline for an extended period of time, we present Pisa, the first protocol to propose an accountable third party who can be hired by parties to cancel execution forks on their behalf. To evaluate Pisa, we provide a proof-of-concept implementation for a simplified Sprites and we demonstrate that it is cost-efficient to deploy on the Ethereum network.
Blockchain, a potentially disruptive technology, advances many different applications, e.g., crypto-currencies, supply chains, and the Internet of Things. Under the hood of blockchain, it is required to handle different kinds of digital assets and data. The next-generation blockchain ecosystem is expected to consist of numerous applications, and each application may have a distinct representation of digital assets. However, digital assets cannot be directly recorded on the blockchain, and a tokenization process is required to format these assets. Tokenization on blockchain will inevitably require a certain level of proper standards to enrich advanced functionalities and enhance interoperable capabilities for future applications. However, due to specific features of digital assets, it is hard to obtain a standard token form to represent all kinds of assets. For example, when considering fungibility, some assets are divisible and identical, commonly referred to as fungible assets. In contrast, others that are not fungible are widely referred to as non-fungible assets. When tokenizing these assets, we are required to follow different tokenization processes. The way to effectively tokenize assets is thus essential and expecting to confront various unprecedented challenges. This paper provides a systematic and comprehensive study of the current progress of tokenization on blockchain. First, we explore general principles and practical schemes to tokenize digital assets for blockchain and classify digitized tokens into three categories: fungible, non-fungible, and semi-fungible. We then focus on discussing the well-known Ethereum standards on non-fungible tokens. Finally, we discuss several critical challenges and some potential research directions to advance the research on exploring the tokenization process on the blockchain. To the best of our knowledge, this is the first systematic study for tokenization on blockchain.
Blockchain is an emerging technology that promises many exciting applications in various fields, including financial, medical, energy, and logistics management. However, there are still some limitations in the existing blockchain framework that prevents its widespread adoption in the commercial world. One important limitation is the storage requirement, wherein each blockchain node has to store a copy of the distributed ledger. Thus, as the number of transactions increases, this storage requirement grows quadratically, eventually limiting the scalability of a blockchain system. Moreover, the public ledger in a blockchain framework allows anyone in the network to audit the transaction, which may not be favourable in some privacy-sensitive applications. In this paper, a secret-sharing scheme is proposed to reduce the size of the blockchain transactions. Each transaction block is divided into t parts, and the size of each part is 1/ t size of transaction block. We use the secret-sharing mechanism to share t parts into n shares. Hence, each node stores not one transaction but one share in the blockchain system. The proposed scheme can eventually reduce the storage cost of a blockchain transaction by 1/ t without introducing an additional recovery communication cost; however, robustness is reduced in node failure as a tradeoff. Meanwhile, the proposed scheme was more efficient and secure compared to other state-of-the-art schemes that aim to reduce blockchain storage for industrial big data.
Mirko Koscina, David Manset, Claudia Negri-Ribalta, Octavio Pérez Kempner
We propose a new healthcare data exchange platform for research centers, hospitals and healthcare institutions. Our model is based on a federated blockchain network that interconnect the healthcare institutions and orchestrate the data life cycle from the data publication to the data consumption. The blockchain is responsabible to keep the traceability of the whole process and we use a specially designed smart contract to control the data sharing process. Moreover, we provide the means to enforce GDPR and thus achieve a GDPR compliant model.
Cloud computing has made the software development process fast and flexible but on the other hand it has contributed to increasing security attacks. Employees who manage the data in cloud companies may face insider attack, affecting their reputation. They have the advantage of accessing the user data by interacting with the authentication mechanism. The primary aim of this research paper is to provide a novel secure authentication mechanism by using Blockchain technology for cloud databases. Blockchain makes it difficult to change user login credentials details in the user authentication process by an insider. The insider is not able to access the user authentication data due to the distributed ledger-based authentication scheme. Activity of insider can be traced and cannot be changed. Both insider and outsider user's are authenticated using individual IDs and signatures. Furthermore, the user access control on the cloud database is also authenticated. The algorithm and theorem of the proposed mechanism have been given to demonstrate the applicability and correctness.The proposed mechanism is tested on the Scyther formal system tool against denial of service, impersonation, offline guessing, and no replay attacks. Scyther results show that the proposed methodology is secure cum robust.
Open access
Blockchain Technology Applications and Security
Cloud Data Security Solutions
Advanced Steganography and Watermarking Techniques
Yili Luo, Fan Jia, Chunhua Deng, Yixin Li · 6 authors
Nowadays, data has been more intensive and collaborative than in the past. In this paper, we propose a new accountable data sharing scheme based on blockchain and SGX, in which data subscription undeniable. By utilizing blockchain, the records of users data sharing acts are tamper-resistant, and our scheme no longer needs a trusted third party. SGX ensures the confidentiality of sharing data.
With the wide-spread use of blockchain technology, Byzantine fault-tolerant (BFT) protocols are explored as a means to achieve consensus on which transactions should be processed next. BFT protocols are not a one-size-fits-all solution: they should be chosen according to the blockchain's use case, which can range from supply chain management to decentralised storage, requiring specialisation e.g. regarding throughput, latency, or level of decentralisation. Previously, consensus protocols were usually hardcoded into the blockchain infrastructure and could not be exchanged, therefore inhibiting flexible use of an otherwise generic blockchain infrastructure. Hyperledger Fabric claims to provide modular consensus and support for crash-fault and Byzantine fault tolerant protocols. However, integrating a BFT protocol has shown that Fabric's architecture is currently not well-suited for this fault model as it requires substantial changes and thereby breaks Fabric's modularity. This also has to be repeated for each integrated BFT protocol. In this paper, we present Bloxy, a blockchain-aware trusted proxy running on the replica that encapsulates all BFT client functionality. Bloxy enables transparent access to generic BFT frameworks and preserves Fabric's modularity even for the Byzantine fault model. It runs inside a trusted execution environment based on Intel's Software Guard Extensions. Bloxy offers blockchain-specific communication mechanisms as well as short-term block storage to handle crashes or disconnects to ensure that all nodes receive block updates. We implemented two Bloxy-based ordering services based on PBFT and the hybrid BFT protocol Hybster. Our evaluation shows that our approach increases throughput by up to 71% compared to directly integrated BFT protocols.
Marco Autili, Francesco Gallo, Paola Inverardi, Claudio Pompilio · 5 authors
Business process management is concerned with the design execution, improvement, and monitoring of business processes. Systems that support the enactment and execution of processes have extensively been used by companies to streamline and automate intra-organizational processes. However, today's business enterprises must deal with global competition, heterogeneity, and rapidly develop new services and products. To address these requirements, the services reuse-based approach allowed enterprises to reconsider and optimize the way they do business, and change their information systems and applications to support collaborative business processes. Service choreographies support the reuse-based service-oriented philosophy in that they represent a powerful and flexible approach to realize systems by (possibly) reusing services and composing them in a fully distributed way. Nevertheless, for inter-organizational processes, challenges of collaborative design and lack of mutual trust have hampered a broader uptake. In this paper, we show an early stage approach to address the problem of trust in services choreography by using Blockchain technologies, in order to support the decentralized and peer-to-peer collaboration in a trustworthy manner, even in a network without any mutual trust between nodes.
Blockchain is an emerging technology that has many potential applications. The blockchain contains a certain and verifiable record of every single transaction ever made. In this paper, we introduce the application for the prevention of potential plagiarism based on decentralized architecture and public-key cryptosystem, such that no need for trusted third party. We use SHA-256 as hash function and Elliptic Curve as digital signature algorithm. The results show that any attempt to plagiarize a submitted paper will violate the rules. The transmission of a paper is also encrypted through the use of complex cryptographic principles and security algorithms such that nobody can see or alter the paper. Even the reviewer is unable to change the paper because by doing such action the blockchain will report the violation.
The following topics are dealt with: learning (artificial intelligence); cryptography; distributed databases; feature extraction; Internet; cryptocurrencies; cryptographic protocols; neural nets; authorisation; Internet of Things.
Long-term archival storage systems must protect data from powerful attackers that might try to corrupt or censor (part of) the documents. They must also protect the corresponding metadata information, which is essential to maintain and rebuild the stored data. In this practical experience report, we present metablock, a metadata protection system leveraging the Ethereum distributed ledger. We combine metablock with an existing secure long-term data archival system to provide a scalable design that allows external auditing, data validation and efficient data repair. We reflect on our experiences in using a blockchain for metadata protection, with the goal of providing valuable insights and lessons for developers of such secure systems, by highlighting the potential and limitations of the approach. Our prototype is available at https://github.com/ArnaudLhutereau/mb.
Electronic Medical Records (EMRs) contain private and sensitive information of the patients and require distribution across multiple stakeholders for sustained and consistent medical care. EMRs are owned and maintained by hospital systems. So, patients often face difficulties in getting their data shared among different stakeholders. Blockchain provides distributed, transparent, and immutable log of records that benefit the design of healthcare systems. There have been several studies done to use Blockchain technology as a mediation tool for sharing sensitive EMRs between multiple stakeholders in the e-health care system. However, these studies lack the requirement of patients to have full control over their EMR data. This work develops PACEX, PAtient-Centric EMR eXchange, that enables patients to share and have complete control over their data using Blockchain. In PACEX, we develop an easy-to-use patient application that interacts with different hospital systems and handles EMR exchanges with integrity. We developed a proof of concept implementation of PACEX using Ethereum Blockchain and Smart Contracts to achieve access control and maintain a history of record exchanges among different stakeholders. The evaluation results provide the quantitative analysis that gives time estimates for various transactions involved in PACEX and the qualitative analysis that describes the security properties of the system. PACEX achieves essential security requirements such as Authentication, Integrity, Access Control, and Traceability over the EMR data exchange.
As supply chain has become extremely complicated, traditional supply chain management schemes reveal limitations in keeping track of resources for efficient risk management. Recently, blockchain-based solutions for supply chain have shown possibility to overcome those limits. However, numerous practical problems in this research domain are not fully explored up to date. Thus, we delve into one of the most significant problems among them: verification of business logic in transactions. In this paper, we propose a novel distributed ledger system for supply chain, enabled by anomaly detection framework that verifies semantic correctness of transactions based on business context data. Our blockchain data model is tailored to accurately represent events occurred in supply chain based on real-world business standards. In order to facilitate more efficient tracking of provenance, we leverage graph data model to represent supply chain network. On top of the data model, we present smart contract-based anomaly detection framework that verifies whether a transaction is anomalous. Generic rule-based and graph-based detection methods are devised. The feasibility of our proposed model is shown by the system implemented using Hyperledger Sawtooth. We show how our anomaly detection layer can be plugged into the system: how it interacts with other system components, and how overall system flow works with this new function. We evaluate our system with scenario-based simulations. For a number of use cases we synthesized, the correctness and effectiveness of our system are demonstrated.
Fernando Richter Vidal, Feliz Ribeiro Gouveia, Christophe Soares
The authenticity of academic diplomas is a matter of great concern for employers and other authorities to verify the authenticity of academic degrees. The issuing institutions may have closed or fail to keep accurate records. In these situations, the verification of academic diplomas launches challenges. In a worldwide education market, many institutions are involved, and it becomes even harder to keep track and handle different approaches/procedures to verify the status and authenticity of diplomas. As in many other areas, the blockchain technology surges as a promising solution to the referred problem. In this paper, we propose an approach using this technology implemented in University Fernando Pessoa. We also discuss the new challenges in security and implementation raised by the usage of this technology.
Iman Vakilinia, Shahin Vakilinia, Shahriar Badsha, Engin Arslan · 5 authors
Blockchain technology has provided a solid system to develop incentivization algorithms using the smart contract. Blockchain applies the distributed ledger to store transaction histories, and the information is stored across a network of computers instead of on a single server. This facilitates the development of a new set of applications such as distributed file storage systems where users can rent out their storage in return for a premium. The distributed file storage systems provide more privacy and security compared to the centralized storage models as there is no need to have a trusted party. New schemes have been developed for distributed file storage systems on top of the blockchain platform, however, the problem of task/service allocation in these models have not been studied before. In this paper, we study the task/service allocation in the distributed file storage systems considering the challenge of computation cost. First, we formalize the problem of task/service allocation in a decentralized storage network, and then we discuss different approaches to allocate storage tasks to storage servers in an efficient manner. Moreover, we study the benefits of the cooperation (a.k.a pooling) in the storage and retrieval markets of distributed storage networks. The evaluation results show the benefit of our proposed pooling based approach in storage and retrieval markets.
The term “smart contracts” has become ubiquitous to describe an enormous number of programs uploaded to the popular Ethereum blockchain system. Despite rapid growth of the smart contract ecosystem, errors and exploitations have been constantly reported from online contract systems, which has put financial stability at risk with losses totaling millions of US dollars. Most existing research focuses on pinpointing specific types of vulnerabilities using known patterns. However, due to the lack of awareness of the inherent nondeterminism in the Ethereum blockchain system and how it affects the funds transfer of smart contracts, there can be unknown vulnerabilities that may be exploited by attackers to access numerous online smart contracts. \n \nIn this paper, we introduce a methodical approach to understanding the inherent nondeterminism in the Ethereum blockchain system and its (unwanted) influence on contract payments. We show that our new focus on nondeterminism-related smart contract payment bugs captures the root causes of many common vulnerabilities without relying on any known patterns and also encompasses recently disclosed issues that are not handled by existing research. To do so, we introduce techniques to systematically model components in the contract execution context and to expose various nondeterministic factors that are not yet fully understood. We further study how these nondeterministic factors impact contract funds transfer using information flow tracking. The technical challenge of detecting nondeterministic payments lies in discovering the contract global variables subtly affected by read-write hazards because of unpredictable transaction scheduling and external callee behavior. We show how to augment and instrument a contract program into a representation that simulates the execution of a large subset of the contract behavior. The instrumented code is then analyzed to flag nondeterministic global variables using off-the-shelf model checkers. \n \nWe implement the proposed techniques as a practical tool named NPChecker (Nondeterministic Payment Checker) and evaluate it on 30K online contracts (3,075 distinct) collected from the Ethereum mainnet. NPChecker has successfully detected nondeterministic payments in 1,111 online contracts with reasonable cost. Further investigation reports high precision of NPChecker (only four false positives in a manual study of 50 contracts). We also show that NPChecker unveils contracts vulnerable to recently-disclosed attack vectors. NPChecker can identify all six new vulnerabilities or variants of common smart contract vulnerabilities that are missed by existing research relying on a “contract vulnerability checklist.”