Most popular blockchain solutions, like Bitcoin, rely on proof-of-work, guaranteeing that the output of the consensus is agreed upon with high probability. However, this probability depends on the delivery of messages and that the computational power of the system is sufficiently scattered among pools of nodes in the network so that no pool can mine more blocks faster than the crowd. New approaches, like Ethereum, generalise the proof-of-work approach by letting individuals deploy their own private blockchain with high transaction throughput. As companies are starting to deploy private chains, it has become crucial to better understand the guarantees blockchains offer in such a small and controlled environment. In this paper, we present the \emph{Blockchain Anomaly}, an execution that we experienced when building our private chain at NICTA/Data61. Even though this anomaly has never been acknowledged before, it may translate into dramatic consequences for the user of blockchains. Named after the infamous Paxos anomaly, this anomaly makes dependent transactions, like "Bob sends money to Carole after he received money from Alice" impossible. This anomaly relies on the fact that existing blockchains do not ensure consensus safety deterministically: there is no way for Bob to make sure that Alice actually sent him coins without Bob using an external mechanism, like converting these coins into a fiat currency that allows him to withdraw. We also explore smart contracts as a potential alternative to transactions in order to freeze coins, and show implementations of smart contract that can suffer from the Blockchain anomaly and others that may cope with it.
The Internet of Things and Services (IoTS) has encouraged the development of service provisioning systems in respect to Smart City topics. Most of them are operated as heterogeneous systems which limits end customers’ access and contradicts with IoTS principles. In this paper, we discuss and develop a reference model of an interconnected service marketplace ecosystem. The prototypical implementation incorporates findings from an empirical study and lessons learned from research projects. The elaborated ecosystem enables service request roaming between different parties across system boundaries. The paper presents a feasible centralized architecture, introduces involved parties and parts of a developed message protocol. Why a contracting mechanism is indispensable for request roaming is also outlined. The model’s feasibility is demonstrated by means of a current electric mobility use case: providing access to foreign charging infrastructure without multiple registrations. This work contributes to simplify the data exchange between service platforms to improve Smart City solutions and to support travelers with intelligent mobility applications.
Eleftherios Kokoris-Kogias, Philipp Jovanovic, Nicolas Gailly, Ismail Khoffi · 6 authors
While showing great promise, Bitcoin requires users to wait tens of minutes\nfor transactions to commit, and even then, offering only probabilistic\nguarantees. This paper introduces ByzCoin, a novel Byzantine consensus protocol\nthat leverages scalable collective signing to commit Bitcoin transactions\nirreversibly within seconds. ByzCoin achieves Byzantine consensus while\npreserving Bitcoin's open membership by dynamically forming hash\npower-proportionate consensus groups that represent recently-successful block\nminers. ByzCoin employs communication trees to optimize transaction commitment\nand verification under normal operation while guaranteeing safety and liveness\nunder Byzantine faults, up to a near-optimal tolerance of f faulty group\nmembers among 3f + 2 total. ByzCoin mitigates double spending and selfish\nmining attacks by producing collectively signed transaction blocks within one\nminute of transaction submission. Tree-structured communication further reduces\nthis latency to less than 30 seconds. Due to these optimizations, ByzCoin\nachieves a throughput higher than PayPal currently handles, with a confirmation\nlatency of 15-20 seconds.\n
We need to shift our perspective of blockchain, from just the programmable ledger, to a networked infrastructure of computing machinery. Doing so, we could easily visualize how computer programs will operate over this new infrastructure, which is presently being used for transaction validations. We cannot take the cloud computing analogy literally because the blockchain infrastructure can’t replace cloud computing completely. Although, it unbundles and democratizes cloud computing. Thus, companies and individual consumers can soon keep their data in distributed cloud network based on highly secure blockchain technology.
Scott Ruoti, Ben Kaiser, Arkady Yerukhimovich, Jeremy Clark · 5 authors
This paper explains the functioning of “blockchain technology” and critically assesses its potential role in improving services in banking, contracts, and database systems. Comparing blockchain to the current best practice technology in these fields reveals several barriers to successful commercial implementation: Blockchain technology involves costly redundancies and irreversibility, faces serious scaling problems and significant barriers to complying with regulations, and is a security liability unless secured with its own freely trading currency. A survey of the state of the blockchain industry shows that in eight years since blockchain technology was invented, it has had no commercial applications other than digital cash. The paper concludes that a blockchain is a peculiar engineering design whose only advantage is in removing third party intermediation to allow for the creation of digital cash, and is unlikely to offer economic advantages for any commercial problem other than the one it was specifically engineered to solve.
Steve Huckle, Rituparna Bhattacharya, Martin White, Natalia Beloff
This paper explores how the Internet of Things and blockchain technology can benefit shared economy applications. The focus of this research is understanding how blockchain can be exploited to create decentralised, shared economy applications that allow people to monetise, securely, their things to create more wealth. Shared economy applications such as Airbnb and Uber are well-known applications, but there are many other opportunities to share in the digital economy. With the recent interest in the Internet of Things and blockchain, the opportunity exists to create a myriad of sharing applications, e.g. peer-to-peer automatic payment mechanisms, foreign exchange platforms, digital rights management and cultural heritage to name but a few. While many types of shared economy scenarios are proliferating, few of them, so far, leverage the Internet of Things and blockchain as technologies to build distributed applications. This paper discusses how we might make use of the Internet of Things and blockchains to create secure shared economy distributed applications. Presented are examples of such distributed applications in the context of an Internet of Things architecture using blockchain technology.
Internet of Things (IoT) are being adopted for industrial and manufacturing applications such as manufacturing automation, remote machine diagnostics, prognostic health management of industrial machines and supply chain management. Cloud-Based Manufacturing is a recent on-demand model of manufacturing that is leveraging IoT technologies. While Cloud-Based Manufacturing enables on-demand access to manufacturing resources, a trusted intermediary is required for transactions between the users who wish to avail manufacturing services. We present a decentralized, peer-to-peer platform called BPIIoT for Industrial Internet of Things based on the Block chain technology. With the use of Blockchain technology, the BPIIoT platform enables peers in a decentralized, trustless, peer-to-peer network to interact with each other without the need for a trusted intermediary.
Ángel Gomez-Sacristan, Miguel A. Rodríguez-Hernández, V. Sempere
The concept of Smart-Hospital is generally associated with a comprehensive care model capable of responding to the needs of health institutions, companies and patients in an optimum way in terms of economic, operative and environmental aspects aiming the improvement of care quality and sustainable use of resources. In this context, a Smart-Hospital is a technological and hyper-connected hospital in terms of telecommunications. Ahuge range of systems and devices generate information of a heterogeneous nature. In many cases, for reasons of efficiency and availability, this information is stored and processed in architectures external to the hospital itself. Centralized services housed in Cloud architectures or telemedicine / tele-assistance services are proof of this. Guaranteeing an adequate level of quality of service is a complex task when approached from an analytical point of view due to the large number of sources and their heterogeneous nature. The use of simulation tools allows this task to be undertaken and using different hypotheses in less time and at a reasonable cost. This article presents the results obtained, in terms of quality of communications, for a Smart-Hospital with an arbitrary collection of heterogeneous services connected by Metro-Ethernet access. The results obtained: loss of information, delays and jitter will be used to outline the capacities to be contracted from the telecommunications supplier.
Kay Noyen, Dirk Volland, Dominic Wörner, Elgar Fleisch
Sensing-as-a-Service (S2aaS) is an emerging Internet of Things (IOT) business\nmodel pattern. To be technically feasible and to effectively allow for broad\nadoption, S2aaS implementations have to overcome manifold systemic hurdles,\nspecifically regarding payment and sensor identification. In an effort to\novercome these hurdles, we propose Bitcoin as protocol for S2aaS networks. To\nlay the groundwork and start the conversation about disruptive changes that\nBitcoin technology could bring to S2aaS concepts and IOT in general, we\nidentify and discuss the core characteristics that could drive those changes.\nWe present a conceptual example and describe the basic process of exchanging\ndata for cash using Bitcoin.\n
Ubiquitous sensing enabled by Wireless Sensor Network (WSN) technologies cuts across many areas of modern day living. This offers the ability to measure, infer and understand environmental indicators, from delicate ecologies and natural resources to urban environments. The proliferation of these devices in a communicating-actuating network creates the Internet of Things (IoT), wherein, sensors and actuators blend seamlessly with the environment around us, and the information is shared across platforms in order to develop a common operating picture (COP). Fuelled by the recent adaptation of a variety of enabling device technologies such as RFID tags and readers, near field communication (NFC) devices and embedded sensor and actuator nodes, the IoT has stepped out of its infancy and is the the next revolutionary technology in transforming the Internet into a fully integrated Future Internet. As we move from www (static pages web) to web2 (social networking web) to web3 (ubiquitous computing web), the need for data-on-demand using sophisticated intuitive queries increases significantly. This paper presents a cloud centric vision for worldwide implementation of Internet of Things. The key enabling technologies and application domains that are likely to drive IoT research in the near future are discussed. A cloud implementation using Aneka, which is based on interaction of private and public clouds is presented. We conclude our IoT vision by expanding on the need for convergence of WSN, the Internet and distributed computing directed at technological research community.
Ubiquitous sensing enabled by Wireless Sensor Network (WSN) technologies cuts\nacross many areas of modern day living. This offers the ability to measure,\ninfer and understand environmental indicators, from delicate ecologies and\nnatural resources to urban environments. The proliferation of these devices in\na communicating-actuating network creates the Internet of Things (IoT),\nwherein, sensors and actuators blend seamlessly with the environment around us,\nand the information is shared across platforms in order to develop a common\noperating picture (COP). Fuelled by the recent adaptation of a variety of\nenabling device technologies such as RFID tags and readers, near field\ncommunication (NFC) devices and embedded sensor and actuator nodes, the IoT has\nstepped out of its infancy and is the the next revolutionary technology in\ntransforming the Internet into a fully integrated Future Internet. As we move\nfrom www (static pages web) to web2 (social networking web) to web3 (ubiquitous\ncomputing web), the need for data-on-demand using sophisticated intuitive\nqueries increases significantly. This paper presents a cloud centric vision for\nworldwide implementation of Internet of Things. The key enabling technologies\nand application domains that are likely to drive IoT research in the near\nfuture are discussed. A cloud implementation using Aneka, which is based on\ninteraction of private and public clouds is presented. We conclude our IoT\nvision by expanding on the need for convergence of WSN, the Internet and\ndistributed computing directed at technological research community.\n
Blockchain technology has been gaining great interest from a variety of sectors including healthcare, supply chain, and cryptocurrencies. However, Blockchain suffers from a limited ability to scale (i.e., low throughput and high latency). Several solutions have been proposed to tackle this. In particular, sharding has proved to be one of the most promising solutions to Blockchain's scalability issue. Sharding can be divided into two major categories: (1) Sharding-based Proof-of-Work (PoW) Blockchain protocols, and (2) Sharding-based Proof-of-Stake (PoS) Blockchain protocols. The two categories achieve good performances (i.e., good throughput with a reasonable latency), but raise security issues. This article focuses on the second category. In this paper, we start by introducing the key components of sharding-based PoS Blockchain protocols. We then briefly introduce two consensus mechanisms, namely PoS and practical Byzantine Fault Tolerance (pBFT), and discuss their use and limitations in the context of sharding-based Blockchain protocols. Next, we provide a probabilistic model to analyze the security of these protocols. More specifically, we compute the probability of committing a faulty block and measure the security by computing the number of years to fail. We achieve a number of years to fail of approximately 4000 in a network of 4000 nodes, 10 shards, and a shard resiliency of 33%.
Usman Khalil, Owais Ahmed Malik, Wee-Hong Ong, Mueen Uddin
The concept of smart city architecture requires a comprehensive solution that can combine real-time response applications for cyber-physical systems. However, the architecture faces challenges that can obstruct the operations in terms of systems, processes, and data flow as far as the breach risk is concerned. Though the field has been researched with the existence of centralized and distributed architectures to support smart cities. Research gaps regarding security concerns, platform assistance, and resource management continue to persist. This research article presents a novel blockchain-based architecture that proposes expansion in the non-fungible tokens (NFTs) to cater to the expansion of IoT-enabled smart assets. It enables NFTs to employ fog computing for all users and smart devices connected to a fog node in a cyber-physical system. The proposed expansion suggested in Non-Fungible Tokens (NFTs) for IoT assets representation in a cyber-physical system, provides devices and user identification and authentication functionality. The proposed NFT architecture has been designed to provide a smart city solution for cyber-physical systems that ensures robust security features (such as CIA) by introducing new attributes and functions for Owner, User, Fog, and IoT device/s authentication. The validation and rigor of the security services, efficiency, and latency have been achieved by deployments on private and public ledgers. The efficiency, and cost-effectiveness of the suggested functions and components have been evaluated in terms of evaluation cost and time complexity which resulted in promising results, obtained and validated on a testnet. The evaluation cost for the devised mint component was approximately 81%, and devised approve() was approximately 23% more efficient than other solutions.
Ruy de Queiroz, Luiz Carlos Pereira, Edward Hermann Hæusler
This volume contains the Proceedings of the 10th Workshop on Logic, Language, Information and Computation (WoLLIC'2003). The Workshop was held in Ouro Preto, Minas Gerais, Brazil from July 29 to August 1, 2003, in the Escola de Minas of the Universidade Federal de Ouro Preto ( UFOP ). WoLLIC is a series of workshops which started in 1994 with the aim of fostering interdisciplinary research in pure and applied logic . The idea is to provide a forum which is large enough in the number of possible interactions between logic and the sciences related to information and computation, and yet is small enough to allow for concrete and useful interaction among participants. Previous versions were held at: Recife (Pernambuco, Brazil) in 1994 and 1995; Salvador (Bahia, Brazil) in 1996; Fortaleza (Ceará, Brazil) in 1997; São Paulo (Brazil) in 1998; Itatiaia (Rio de Janeiro, Brazil) in 1999; Natal (Rio Grande do Norte) in 2000; Brasília (Distrito Federal, Brazil) in 2001; Rio de Janeiro (Brazil) in 2002. Scientific sponsorship comes from the Interest Group in Pure and Applied Logics ( IGPL ), the European Association for Logic, Language and Information ( FoLLI ), the Association for Symbolic Logic ( ASL ), European Association for Theoretical Computer Science ( EATCS ), the Sociedade Brasileira de Computação ( SBC ), and the Sociedade Brasileira de Lógica ( SBL ). Funding was kindly given by:(i) CNPq ( Conselho Nacional de Desenvolvimento Científico e Tecnológico , the scientific and technological development council of the Brazilian Ministério da Ciência e Tecnologia ) (grant 450709/2003-5);(ii) CAPES ( Fundação Coordenação de Apoio ao Aperfeiçoamento de Pessoal de Nível Superior , a Foundation for the Development of Higher-Education under the Brazilian Ministério da Educação e do Desporto ) (grant PAEP0565/03);(iii) FAPEMIG ( Fundação de Amparo à Pesquisa do Estado de Minas Gerais , the Minas Gerais state foundation for the support of scientific research);(iv) Escola de Minas da UFOP ( Universidade Federal de Ouro Preto ). Contributions were received in the form of short papers in all areas related to logic, language, information and computation, including:pure logical systems, proof theory, model theory, algebraic logic, type theory, category theory, constructive mathematics, lambda and combinatorial calculi, program logic and program semantics, logics and models of concurrency, logic and complexity theory, proof complexity, foundations of cryptography (zero-knowledge proofs), descriptive complexity, nonclassical logics, nonmonotonic logic, logic and language, discourse representation, logic and artificial intelligence, automated deduction, foundations of logic programming, logic and computation, and logic engineering. Apart from the contributed papers (15), and the invited talks (5), the programme includes 5 tutorial lectures: 1. Algorithmic Randomness and Derandomization by Eric Allender (Department of Computer Science, Rutgers, the State University of New Jersey, USA) 2. Generalized Quantifiers by Lauri Hella (Department of Mathematics, Statistics and Philosophy, University of Tampere, Finland) 3. Implicit computational complexity by Jean-Baptiste Joinet (Preuves-Programmes-Systèmes, Université Paris 7, France) 4. Proof search foundations for logic programming by Dale Miller (INRIA/Futurs/Saclay, and Laboratoire d'Informatique, École Polytechnique, France) 5. Iterated theory change by Hans Rott (Institut für Philosophie, Universität Regensburg, Germany) All papers in the volume were reviewed by the program committee consisting of Mauricio Ayala-Rinóon ( Departamento de Matemática, Universidade de Brasília, Brazil ) Argimiro Arratia ( Depto. Matematicas, Universidad Simon Bolivar, Venezuela ) Alessandra Carbone ( Institut des Hautes Études Scientifiques, and Université de Paris XII, France ) Marcelo Coniglio ( Centro de Lógica e Epistemologia, Universidade Estadual de Campinas, Brazil ) Gilles Dowek ( INRIA, France ) Arnaud Fleury ( Facoltà di Scienze, Università di Verona, Italy ) Dexter Kozen ( Cornell University, USA ) Maarten Marx ( ILLC, Faculty of Science, Universiteit Amsterdam, The Netherlands ) Anto˚nio Carlos da Rocha Costa ( Escola de Informática, Universidade Católica de Pelotas, Brazil ) Dieter Spreen ( Fachbereich Mathematik, Theoretische Informatik, Universität Siegen, Germany ) Luiz Carlos Pereira ( Departamento de Filosofia, PUC-Rio and UFRJ, Brazil ) Jouko Väänänen ( Department of Mathematics, University of Helsinki, Finland ) Renata Wassermann ( Departamento de Cie˚ncia da Computação, Instituto de Matemática e Estatística, Universidade de São Paulo, Brazil ) The organising committee consisted of Lucília Figueiredo ( Departamento de Computação, Universidade Federal de Ouro Preto, Brazil ) Fred Ulisses Maranhão ( Centro de Informática, Universidade Federal de Pernambuco, Brazil ) Anjolina Grisi de Oliveira ( Center of Informatics, Universidade Federal de Pernambuco, Brazil ) Elaine Pimentel ( Departamento de Matemática, Universidade Federal de Minas Gerais, Brazil ) (Co-Chair) Ruy de Queiroz ( Center of Informatics, Universidade Federal de Pernambuco, Brazil ) (Co-Chair) Maria Angela Weiss ( Departamento de Matemática, Universidade de São Paulo, Brazil ) The volume will be published as volume 84 in the series Electronic Notes in Theoretical Computer Science ( ENTCS ). This series is published electronically through the facilities of Elsevier B.V. and its auspices. The volumes in the ENTCS series can be accessed at the URL http://www.elsevier.nl/locate/entcs A printed version of the current volume has been distributed to the participants at the workshop in Ouro Preto. We are very grateful to the following persons, whose help has been crucial for the success of WoLLIC'2003: Mike Mislove, one of the Managing Editors of the ENTCS series, for his assistance with the use of the ENTCS style files; Thanks are also due to the Department of Mathematics of Universidade Federal de Minas Gerais and the Department of Computing of the Universidade Federal de Ouro Preto, which has provided the logistic support to the organising committee. August 2, 2003 Ruy de Queiroz, Elaine Pimentel, Lucilia Figueiredo