Amit K. Chopra, Samuel H. Christie, Munindar P. Singh
Interaction-Oriented Programming (IOP) refers to multiagent concepts, languages, and programming models for engineering applications that are characterized by interactions between autonomous parties. Such applications arise in domains such as e-commerce, health care, and finance. Owing to the autonomy of the principals involved, such applications are conceptually decentralized. We demonstrate how to specify a decentralized application flexibly and how to engineer correct, fault-tolerant endpoints (agents) for the principals in a straightforward manner. Notably, the entire application is realized as agents communicating over an unordered, unreliable messaging infrastructure (our implementations in fact use UDP). IOP departs from traditional distributed systems approaches that rely on guarantees in the application's communication infrastructure, e.g., for ordering and fault tolerance. Notably, IOP shows how to address application semantics, the holy grail of distributed systems.
Andrea Tesei, Domenico Lattuca, Alexandr Tardo, Luca Di Mauro · 8 authors
Major maritime carriers are globally demanding improvements in the efficiency of port operations. Cargo carried by ships must be loaded and unloaded quickly with minimal stopover time in the port. This requirement mandates seaports to deploy cutting-edge technology to the port area so that logistic processes are increasingly efficient and reliable. In this scenario, the attack surface of such critical infrastructure is growing very rapidly and advanced security techniques must be deployed to enforce a high attack resilience. A Distributed Ledger-based Credential Management System exploiting a Distributed Ledger Technology (DLT) to enable transparent and real-time tracking of logistic vehicles and cargos within a terminal is presented in this paper. Based on a customization of Vehicular Ad-Hoc Network (VANET) security standards, the proposed scheme provides authentication, authorization, and revocation capabilities to promptly exclude misbehaving logistic vehicles from the system, while maintaining an immutable record of all the logistic vehicles' activity. The laboratory validation demonstrates that the delay of the devised scheme is not dependent on the quay area capacity, thus being applicable in seaports of any size. Furthermore, the effectiveness of the solution is demonstrated with the field trial results obtained with the EU Horizon 2020 COREALIS project testbed deployed in the Port of Livorno.
The U.S. Navy seeks to leverage emerging technologies to manage massive amounts of data from multiple geographically separated systems. It is aware of the importance of data usage and data transfer in supporting its operations. Data management requires a data transfer system that is safe, fast, and scalable. Autonomous Navy Unclassified Software Distribution (ANUSD) is an application for delivering software to all nodes on the Navy's enterprise network based on blockchain technology. Blockchain is the right candidate and emerging solution to ensure the triad of confidentiality, integrity, and availability. In this thesis, we perform a comparison of public blockchain and private blockchain with the aim of determining which one would perform better in conjunction with ANUSD. We used an IBM Hyperledger (private blockchain) network and an Ethereum blockchain (public blockchain) network as the basis of the comparative analysis of their latency and scalability. We compared the transactions per second (TPS) achieved with Ethereum against that of Hyperledger with the ANUSD application installed. The results showed that as we scaled up the Ethereum network, there was a significant increase in TPS. In contrast, increasing scalability did not have a significant impact on TPS for the Hyperledger network.
The articles in this special section focus on distributed ledger technologies (DLT). DLT, of which blockchain is a popular example, are increasingly becoming a popular means to maintain transactional integrity and achieve consensus among competing parties in many modern distributed data exchanges. Indeed, a Gartner survey estimates that by 2020, DLT and blockchain will support the global movement and tracking of $2 trillion of goods and services annually. Unlike centralized files and databases, distributed ledgers rely on peering nodes to record, share, and synchronize transactions and data in their individually maintained local ledgers. In the case of blockchain, information is organized into blocks that are securely and transparently chained together. These blocks become immutable global knowledge among all peers using consensus algorithms to achieve data synchronization. The “append-only, globally accepted” transactions supported by blockchain technologies have given rise to both opportunities and challenges compared to traditional data storage systems. One of the challenges faced by current information sharing systems, and a key concept that makes DLT appealing is the support for the creation of large scale systems from nodes and components that do not trust each other. Being able to reach consensus and share a commonly verifiable ledger is a very powerful primitive, which is already being considered for data sharing applications in energy, pharmaceuticals, and many other domains.
This thesis examines methods which could be used for developing MMORPG games so that there is no single entity that could arbitrarily control game mechanics, virtual assets or other game aspects. The theoretical part systematically analyzes the usual aspects of MMORPG games, then the principles of decentralized cryptocurrencies are presented, and one of them, Ethereum, is analyzed in more detail. Based on this theoretical knowledge, methods are proposed on how to use Ethereum to implement the identified aspects of MMORPG games, and the restrictions which must be imposed on these aspects are recognized. The practical part then introduces a specific implementation of MMORPG game on Ethereum, which demonstrates the above methods. In conclusion, the chosen approach is compared to the games with a common client-server architecture, especially in terms of complexity and gaming costs. 1
Access control management is an integral part of maintaining the security of an application. Although there has been significant work in the field of cloud access control mechanisms, however, with the advent of Distributed Ledger Technology (DLT), on-chain access control management frameworks hardly exist. Existing access control management mechanisms are tightly coupled with the business logic, resulting in governance issues, non-coherent with existing Identity Management Solutions, low security, and compromised usability. We propose a novel framework to implement dynamic role-based access control for decentralized applications (dApps). The framework allows for managing access control on a dApp, which is completely decoupled from the business application and integrates seamlessly with any dApps. The smart contract architecture allows for the independent management of business logic and execution of access control policies. It also facilitates secure, low cost, and a high degree of flexibility of access control management. The proposed framework promotes decentralized governance of access control policies and efficient smart contract upgrades. We also provide quantitative and qualitative metrics for the efficacy and efficiency of the framework. Any Turing complete smart contract programming language is an excellent fit to implement the framework. We expect this framework to benefit enterprise and non-enterprise dApps and provide greater access control flexibility and effective integration with traditional and state of the art identity management solutions.
Budankailu Kumar Subudhi, Faruk Catal, Nikolay Tcholtchev, Kin Tsun Chiu · 7 authors
VoIP-based emergency communication is a promising approach to improving the safety of citizens worldwide. The transition required in this scope includes substituting the legacy PSTN/SS7 based emergency call system by Next Generation IP based components for call establishment and control. Thereby, SIP is used as a session control protocol and RTP as the means to transfer emergency data between the caller and the corresponding Public Safety Access Point (PSAP). The emergency data is not only restricted to voice communication but can cover a rich variety of data, which can be acquired by different means (including the end-user devices) and transmitted over IP. This includes video, geopositioning data, voice, Real-Time Text, and sensor data in line with emerging IoT architectures and approaches. A vital aspect in this scope is given by the performance of the underlying network, including its capability to establish calls in emergencies and to transfer the data required for serving the situation. Therefore, in this paper, we evaluate the computational performance of the most recent VoIP emergency system implementation, which was developed by the H2020-EMYNOS project as a realisation of the EENA NG112 Long Term Definition (LTD) vision. We perform a series of trials and evaluate the performance of the EMYNOS system in a multi-party lab environment established during the project. We evaluate the time needed to perform basic emergency call operations over IP, whilst in parallel generating Internet type of background traffic. Correspondingly, we worked out a methodology and implemented it in our testbed, both of which are presented in the current paper. The obtained numerical results lead to the conclusion that SIP-based emergency services stand a good chance to replace legacy systems when it comes to their performance. Additionally, we also provide a perspective on how the blockchain technology could potentially be put to use to enhance the quality of the next-generation emergency services. We propose the utilisation of blockchain technology for tracking emergency calls and enabling efficient recognition of fraud calls, which is a critical aspect for PSAP providers concerning the potential denial of service attacks. In this context, we provide evaluations and numerical results based on a private Ethereum based blockchain playground running at the premises of Fraunhofer FOKUS.
We describe MaGPoS, a novel consensus mechanism which is well suited to decentralized blockchain based protocols. MaGPoS is based on a combination of the well known physics of nano-scale magnetism, and previous implementations of proof of stake. This system has been studied by hundreds of thousands of scientists worldwide for over a hundred years, giving it an extreme level of reliability that is needed for a consensus mechanism. We start by explaining the physics, and study the properties that make it particularly beneficial for use in a consensus mechanism. We then show how to apply the physical model to a decentralized network of nodes, each with their own copy of a blockchain. After this, we describe some example calculations that a node in the decentralized network would make, and provide pseudo code for implementation. Finally, we discuss the how the model achieves all of the important properties that one expects of a consensus mechanism.
Abstract Modern distributed data management systems face a new challenge: how can autonomous, mutually distrusting parties cooperate safely and effectively? Addressing this challenge brings up familiar questions from classical distributed systems: how to combine multiple steps into a single atomic action, how to recover from failures, and how to synchronize concurrent access to data. Nevertheless, each of these issues requires rethinking when participants are autonomous and potentially adversarial. We propose the notion of a cross-chain deal , a new way to structure complex distributed computations that manage assets in an adversarial setting. Deals are inspired by classical atomic transactions, but are necessarily different, in important ways, to accommodate the decentralized and untrusting nature of the exchange. We describe novel safety and liveness properties, along with two alternative protocols for implementing cross-chain deals in a system of independent blockchain ledgers. One protocol, based on synchronous communication, is fully decentralized, while the other, based on semi-synchronous communication, requires a globally shared ledger. We also prove that some degree of centralization is required in the semi-synchronous communication model.
The rapid evolution of distributed systems during the 2010s fundamentally altered how software systems were designed, deployed, and operated, particularly in cloud-based and service-oriented environments. As organizations increasingly decomposed monolithic applications into microservices and event-driven components, traditional monitoring approaches centered on host-level metrics and reactive alerting proved insufficient. Failures became probabilistic rather than deterministic, symptoms emerged far from root causes, and system behavior could no longer be fully inferred from static architecture diagrams or predefined dashboards. Within this context, observability emerged not merely as an operational concern but as an engineering discipline that directly influences how systems are designed, instrumented, and evolved over time. Observability driven engineering refers to the practice of designing software systems such that their internal states can be inferred through externally visible signals under real-world operating conditions. By 2019, this concept had gained traction across distributed systems research and industry practice, informed by earlier control theory definitions and reinforced by practical challenges in debugging production microservices. Rather than treating telemetry as an afterthought added during operations, observability driven engineering integrates metrics, logs, and distributed traces into the development lifecycle itself, shaping interface contracts, failure semantics, and deployment strategies. This shift reflects a recognition that correctness, reliability, and performance in complex systems cannot be validated solely through pre-production testing. In regulated domains such as financial services, the need for observability carries additional significance. Payment processing systems, fraud detection pipelines, and ledger services operate under strict latency, consistency, and auditability requirements, while simultaneously being subject to partial failures, traffic bursts, and external dependencies. In such environments, the inability to explain system behavior during anomalies is not merely an inconvenience but a material operational and regulatory risk. Observability driven engineering therefore intersects with compliance obligations, incident response processes, and risk management practices, extending its relevance beyond purely technical concerns. This paper examines observability driven engineering as understood and practiced by May 2019, situating it within the broader evolution of software architecture from monolithic systems to distributed, cloud-native platforms. It synthesizes academic literature and industry experience to articulate a conceptual model for observability-aware system design, emphasizing the relationship between instrumentation, architectural layering, and operational feedback loops.
In this chapter we will learn how to configure Bitcoin’s reference client, also called Bitcoin Core. We will explore some of its many configuration options and learn how to synchronize with its decentralized network. We will also try out the console-based tools and the GUI wallet software. For testing and development, we will learn how to use Bitcoin’s regtest and testnet networks.
In this paper, we describe LUNES-Blockchain, an agent-based simulator of blockchains that is able to exploit Parallel and Distributed Simulation (PADS) techniques to offer a high level of scalability. To assess the preliminary implementation of our simulator, we provide a simplified modelling of the Bitcoin protocol and we study the effect of a security attack on the consensus protocol in which a set of malicious nodes implements a filtering denial of service (i.e. Sybil Attack). The results confirm the viability of the agent-based modelling of blockchains implemented by means of PADS.
Centralized network solution have been around for a long time, despite having a considerable issue of trust, in which users need to rely on the implementation of the system. During unfortunate incidents such as centralized server hacking attacks, users' data can be stolen and distorted, as well as not available while requested. Blockchain is discovered and believed to be a distributed network solution which can mitigate the above issue. \n \nThis bachelor's thesis studies how blockchain network can be integrated into a social financial mobile application. The research is completed by developing a smart contract and connect it with the mobile application. The smart contract is written in the Solidity programming language and run on the Ethereum network.
The process and cost of trading is heavily burdened by paper administration and process [1]. According to the Ministry of Communications and Information (Singapore), the added cost is about 20 per cent [1]. This can be solved by digitizing the bill of lading and putting them on a blockchain-driven distributed ledger. This project leverages on Corda, an open source blockchain platform, to create a proof-ofconcept solution that simplifies and automate many of the functions of the bill of lading. The solution enables storage, transfer, and signing of the bill of lading to be done digitally. Several nodes are created to simulate the parties that are involved in the supply chain processes, with each node having a web front-end to simplify management. Putting it on the Corda network also allows accurate location tracking which is not possible using traditional pen and paper. To do so, a huge network of nodes must be created to serve as the backbone of the infrastructure. The proof-of-concept solution populates a huge network of nodes in a text file that acts as witnesses to transactions that happens on the ledger such as location updates. Thus, the consignor and consignee can now oversee every passing of the shipment and location update. Parties do not have to worry about spoofing of locations with these witness nodes.
Purwono Purwono, Alfian Ma’arif, Wahyu Rahmaniar, Qazi Mazhar ul Haq · 6 authors
Blockchain technology has a promising future in a number of industries and enterprises. Formerly connected to virtual currency like Bitcoin, blockchain has evolved into a versatile technology with many applications. In the upcoming years, it is predicted that blockchain will revolutionize a variety of industries, including banking, supply chain management, healthcare, voting systems, and more. The future of blockchain technology depends critically on its ability to increase security and transparency. By providing a decentralized and unchangeable record, eliminating the need for middlemen, and boosting participant confidence, blockchain promotes secure and traceable transactions. This transparency has the potential to transform whole industries by reducing fraud, streamlining processes, and increasing output. Blockchain also has the power to change financial systems. Blockchain-based smart contracts facilitate faster, more efficient transactions by automating and enforcing contractual agreements without the need for middlemen. By enabling speedier cross-border transactions, reducing costs, and boosting financial inclusion, tokenization and blockchain-based digital currencies have the potential to overturn conventional banking institutions. Blockchain’s key attributes, including decentralization, transparency, immutability, and security, make it a desirable choice for a range of organizations. Cross-border payments, trade finance, and smart contracts are just a few of the financial sector processes that blockchain technology has the potential to enhance and automate, lowering costs and increasing productivity. Additionally, the tamper-resistance of blockchain technology can boost transaction security and reliability, allowing for a wider use in traditional financial institutions. Outside of the financial industry, blockchain technology has a lot of promise, particularly in industries like supply chain management, healthcare, energy, intellectual property, and governance. By enabling transparent and traceable transactions, blockchain may improve supply chain efficiency, ensure product authenticity, and boost customer trust. By facilitating the secure exchange of patient data and research data, the decentralized nature of blockchain technology can enhance data security, interoperability, and privacy in the healthcare sector. A more decentralized and sustainable energy ecosystem may be supported by blockchain technology through peer-to-peer energy exchange, grid management, and monitoring of renewable energy certificates in the energy sector. Additionally, blockchain technology has the potential to transform decentralized governance structures, voting procedures, intellectual property rights, and digital identity management. By allowing people to own and manage their digital identities, blockchain can enhance privacy and reduce identity theft. Blockchain-based voting systems can offer transparency, security, and verifiability, thereby increasing voter turnout and public trust in democratic institutions. Blockchain can also enable the secure and transparent management of intellectual property rights, fostering author credit and just compensation.
A secure communications infrastructure featuring email, chat, and a MIPR application was developed to a proof of concept level using a blockchain database to store the contents. The blockchain, which already provides a completely secure method of exchanging cryptocurrencies, can be extended to any transactional or communications paradigm. Email applications are described in which application-level standard protocols (e.g. SMTP, POP3, IMAP) were enhanced to optionally allow messages to be routed through a blockchain using familiar client applications such as MS Outlook or Thunderbird. Chat applications are discussed similarly, using the IRC protocol and a custom web-based protocol based on Socket. IO. A MIPR application is also featured where the ability of multiple parties to sign documents and release funds is illustrated. The integrity of the blockchain, inherent in its distributed nature, is discussed along with enhanced software to enable quick recovery from a breach.
Bruno Andriamanalimanana, Chen-Fu Chiang, Jorge Novillo, Sam Sengupta · 5 authors
A central problem with distributed ledger technologies involves the latency that must be incurred in processing and verifying transactions to be accepted as permanent records in the ledger. In many applications, high latency is simply not a tolerable aspect of the governance of the ledger. To help reduce latency, we offer a distributed ledger architecture, Tango, that mimics the Iota-tangle design as articulated by Popov [1] in his seminal paper. A main idea is the introduction of a semi-synchronous transaction entry protocol layer. We model periodic pulsed injections into the evaluation layer from the entry layer.
Konstantnim povećanjem postotka ljudske populacije u gradovima povećava se i broj automobila u gradovima. S povećanjem broja automobila dolazi do većeg opterećenja prometa te zahtjeva za novim parkirnim mjestima. Kako bi smanjilo opterećenje prometnica i potražnja za parkirnim mjestima potrebno je osmišljavati nove metode. Jedna od tih metoda je i dijeljenje automobila kojoj je cilj smanjiti vrijeme koje vozilo provode na parkirnom mjestu. Za implementaciju takve metode potrebno je kreirati sustav koji će omogućivati iznajmljivanje i dijeljenje automobila te plaćanje usluge. U ovome radu izraditi će se dio aplikacije za dijeljenje automobila koja će funkcionirati na pametnom ugovoru unutar blockchain-a odnosno distribuiranog zapisnika. Postupak izrade te funkcionalnosti aplikacije objašnjene su unutar rada. Aplikacija se fokusira na plaćanje koristeći pametne ugovore te su opisani ostali dijelovi sustava potrebni za implementaciju aplikacije koje nisu unutar okvira ovoga rada.
Stefano Angieri, Alberto García-Martínez, Bingyang Liu, Zhiwei Yan · 6 authors
The current system to manage the global pool of IP addresses is centralized\nin five transnational organizations, the Regional Internet Registries (RIRs).\nEach of these RIRs manage the address pool for a large number of countries.\nBecause the RIRs are private organizations, they are subject to the legal\nframework of the country where they are based. This configuration results in a\njurisdictional overflow from the legal framework of the countries where the RIR\nis based to all the countries that the RIRs are serving (the countries served\nby the RIRs de facto become subjects of the legal system of the country where\nthe RIR is hosted). The situation is aggravated by the deployment of new\nsecurity techniques such as the RPKI and BGPsec, that enable enforcement of\nallocations by the RIRs. In this paper we present InBlock, a blockchain-based\ndistributed governance body aimed to provide de-centralized management of IP\naddresses. InBlock also aims to fulfil the same objectives as the current IP\naddress allocation system, namely, uniqueness, fairness, conservation,\naggregation, registration and minimized overhead. InBlock is implemented as a\nDecentralized Autonomous Organization, i.e., as a set of blockchain's smart\ncontracts in Ethereum. Any entity may request an allocation of addresses to the\nInBlock registry by solely performing a (crypto)currency transfer to the\nInBlock. The fee required, along with the annual renewal fee, serves as a\nmechanism to deter stockpiling and other wasteful practices. As with any novel\ntechnology, there are many open questions about the usage of blockchains to\nbuild an IP address registry. For this reason, we believe that practical\nexperimentation is required in order to have hands-on experiences about such a\nsystem. We propose to conduct an experiment on distributed address management\nusing InBlock as a starting point to inform future directions in this area.\n