Modern IT technologies shaped the shift in economic models with many advantages on cost, optimization, and time to market. This economic shift has increased the need for transparency and traceability in supply chain platforms to achieve trust among partners. Distributed ledger technology (DLT) is proposed to enable supply chains systems with trust requirements. In this paper, we investigate the existing DLT-based supply chain projects to show their technical part and limitations and extract the tools and techniques used to avoid the DLT scalability issue. We then set the requirements for a typical DLT-based supply chain in this context. The analyses are based on the scalability metrics such as computing, data storage, and transaction fees that fit the typical supply chain system. This paper highlights the effects of Blockchain techniques on scalability and their incorporation in supply chains systems. It also presents other existing solutions that can be applied to the supply chain. The investigation shows the necessity of having such tools in supply chains and developing them to achieve an efficient and scalable system. The paper calls for further scalability enhancements throughout introducing new tools and/or reutilize the current ones. Doi: 10.28991/esj-2021-SP1-04 Full Text: PDF

Blockchain brings many added values to modern business systems. However, Blockchain-based applications with massive IoT devices experience some limitations. The limitations are due to the linear structure and the consensus algorithms used in Blockchain that consume the participating nodes' considerable resources. In addition, IoT devices are generally with limited resources and have limited bandwidth connections. IOTA, based on Directed Acyclic Graph (DAG), is a new distributed ledger technology (DLT) for IoT devices. It proves its high scalability by providing parallel data processing. However, DAG is still not mature enough to fully replace Blockchain. In previous work, we proposed combining Blockchain and IOTA technologies to allow scalable transactions where Blockchain is employed in the backend, and Tangle is used in the frontend. This paper considers the proposed solution, focusing mainly on the connector part that intermediates both DLT technologies. The connector is a decentralized software component that supports the interaction between the DLT implicitly. The experiments' results show the flexibility to merge both DLTs using a message queuing protocol that enables smart contracts to run on the Tangle nodes and enriches the new platform with reliability and working offline features.

IOTA is a distributed ledger technology (DLT) platform proposed for the internet of things (IoT) systems in order to tackle the limitations of Blockchain in terms of latency, scalability, and transaction cost. The main concepts used in IOTA to reach this objective are a directed acyclic graph (DAG) based ledger, called Tangle, used instead of the chain of blocks, and a new validation mechanism that, instead of relying on the miners as it is the case in Blockchain, relies on participating nodes that cooperate to validate the new transactions. Due to the different IoT capabilities, IOTA classifies these devices into full and light nodes. The light nodes are nodes with low computing resources which seek full nodes’ help to validate and attach its transaction to the Tangle. The light nodes are manually connected to the full nodes by using the full node IP address or the IOTA client load balancer. This task distribution method overcharges the active full nodes and, thus, reduces the platform’s performance. In this paper, we introduce an efficient mechanism to distribute the tasks fairly among full nodes and hence achieve load balancing. To do so, we consider the task allocation between the nodes by introducing an enhanced resource allocation scheme based on the weight least connection algorithm (WLC). To assess its performance, we investigate and test different implementation scenarios. The results show an improved balancing of data traffic among full nodes based on their weights and number of active connections.

Data transparency is essential in the modern supply chain to improve trust and boost collaboration among partners. In this context, Blockchain is a promising technology to provide full transparency across the entire supply chain. However, Blockchain was originally designed to provide full transparency and uncontrolled data access. This leads many market actors to avoid Blockchain as they fear for their confidentiality. In this paper, we highlight the requirements and challenges of supply chain transparency. We then investigate a set of supply chain projects that tackle data transparency issues by utilizing Blockchain in their core platform in different manners. Furthermore, we analyze the projects’ techniques and the tools utilized to customize transparency. As a result of the projects’ analyses, we identified that further enhancements are needed to set a balance between the data transparency and process opacity required by different partners, to ensure the confidentiality of their processes and to control access to sensitive data.

This paper presents the design and implementation of a new platform that takes into consideration the requirements and constraints resulting from the industrial context based on IoT. This platform combines the “Tangle” and “Blockchain” techniques. Tangle is primarily designed to address scale-up issues and the relatively high cost (time and resource) of transactions in a traditional blockchain-based platform. Unlike the “blockchain” structure, it consists of a solid mathematical foundation called DAG (Direct Acyclic Graph). It uses a validation process in which transactions are entered into the distributed registry after authenticating two other randomly selected transactions according to a Poisson distribution (thus, the locations of the new transactions are chosen using random runs in the graph). Therefore, it is an easily scalable system that does not require mining or transaction fees. We aim to study the integration of Tangle and Blockchain techniques to improve the performance and scalability of distributed registry-based platforms to be adapted in industrial enterprises whose processes incorporate or are based on IoT.

The use of blockchain (BC) technology for IoT-based collaboration platforms is still hindered by its inherent properties, namely, the need for ever-increasing storage and the low scalability. In this paper, we investigate the interoperability requirements between BC and tangle distributed technologies. We propose a new decentralization architecture in which BC and tangle are combined in such a way that the IoT functionality is increased, and storage is enhanced while keeping a high level of reliability, data accessibility, integrity, and security. In our architecture, a BC-based platform installed in the backend, used primarily for data storage and smart contract. In the frontend, the applications are running on a Tangle-based platform so that it fits IoT devices. The architecture, when implemented, will reap the advantages of both technologies while limiting the drawbacks of them. The main part of the proposed approach has been implemented and tested using a GPS data emulator connected to an IOTA node. The received data have been propagated and stored in the deployed BC and IOTA.

In this paper, we consider blockchain technology that enabledthe existence of digital currency and we investigate Bitcoin cryptocurrency application. This technology nowadays represents a new feature that replaces existing client-server core system on top of some distributed systems with many additional features such as high availability, resistance to alteration, fault tolerance and cost reduction. After overviewing how such technology is working, we highlightthe requirements and benefits related to the security, database and network. We mainly focus on answering the most Bitcoin queries including privacy and double spending. Furthermore, as blockchain has potential applications far beyond bitcoin, we draw future insights where applications based blockchain are provisioned in the market in order to be totally or partially independent of the centralized systems and we provide a questionnaire helping organizations for better using the blockchain feasibilities.

Data published online nowadays needs a high level of privacy to gain confidentiality as well as to maintain the privacy laws. The focus on k-anonymity enhancements along the last decade, allows this method to be elected as the starting point of any research. In this paper we focus on the external anonymization through a new method: the « Flexible k-anonymity » . It aims to anonymize external published data, by defining a semantic ontology that distinguishes between sparse and abundant quasi-identifiers, and describes aggregation levels relations, in order to achieve adequate k-blocks. For the validation of our proposal, we apply the aforementioned anonymization method to the Comiqual dataset. Comiqual (Collaborative measurement of internet quality), is a large-scale measurement platform for assessing the internet quality access of mobile and ADSL users by collecting mobility traces and private data related to internet metric values.

The focus on k-anonymity enhancements along the last decade, allows this method to be elected as the point of start for many anonymization researches. In this paper we propose "Contra-Loss", a novel anonymization approach applied at internal level, to enhance local privacy where data is at rest and "Flexible k- anonymity" which aims to apply k-anonymity in most situations by defining a semantic ontology which distinguishes between scanty and abundant quasi-identifiers to achieve adequate k-blocks.