Resumen: El dinero debe ser una de las creaciones humanas más exitosas en términos de extensión y masividad. Sus formas, sin embargo, son múltiples. Por ejemplo, hoy presenciamos un boom de criptomonedas que amenaza con dejar obsoleto al dinero físico. Pero, tal como agudamente muestra este texto, sin importar cuan digital sea una criptomoneda, su creación sí tiene efectos físicos a gran escala, especialmente en términos de consumo energético y huella de carbono.
Η τεχνολογία κατανεμημένου καθολικού είναι μια βάση δεδομένων όσον αφορά τις συναλλαγές που, αντί να αποθηκεύεται σε μια κεντρική τοποθεσία, κατανέμεται σε ένα δίκτυο πολλών υπολογιστών. Συνήθως, όλα τα μέλη του δικτύου μπορούν να διαβάζουν τις πληροφορίες και, ανάλογα με τις άδειες που τους έχουν δοθεί, να προσθέτουν στοιχεία. Ο γνωστότερος τύπος τεχνολογίας κατανεμημένου καθολικού είναι η αλυσίδα συστοιχιών (blockchain). Όπου οι συναλλαγές ομαδοποιούνται σχηματίζοντας συστοιχίες (blocks) οι οποίες συνδέονται μεταξύ τους με χρονολογική σειρά δημιουργώντας μια αλυσίδα (chain). Αυτή είναι και η τεχνολογία πίσω από τα κρυπτονομίσματα τα που ξεκίνησαν με την έλευση του Bitcoin. Η πρόσφατη επικέντρωση στην τεχνολογία της αλυσίδας συστοιχιών προήλθε από την εμπορική επιτυχία του Bitcoin και της προσοχής που έτυχε από τους ερευνητές και τις επιχειρήσεις. Σε αυτή την διπλωματική εργασία ασχολούμαστε με την τρέχουσα κατάσταση της αλυσίδας συστοιχιών και επιπλέον με μια εφαρμογή πέραν των κρυπτονομισμάτων, που ονομάζεται έξυπνο συμβόλαιο. Επιπλέον, συγκρίνουμε πέντε πλατφόρμες αλυσίδας συστοιχιών που μπορούν να υποστηρίξουν έξυπνα συμβόλαια επικεντρώνοντας την ανάλυση σε μια γενική περιγραφή τους, στις κύριες τεχνολογικές ιδιότητές τους και στα χρηματοοικονομικά τους στοιχεία. Επιπρόσθετα, θα παρουσιάσουμε μια ανάλυση κόστους-οφέλους και μια αξιολόγηση ασφάλειας των έξυπνων συμβολαίων σημειώνοντας τα σχετικά θέματα παρέχοντας ένα σύνολο πιθανών λύσεων. Τέλος, θα δείξουμε μια πρακτική εφαρμογή και τη διαδικασία και την ευελιξία της διαδικασίας δημιουργίας ενός έξυπνου συμβολαίου σε ένα περιβάλλον με το διαδίκτυο των πραγμάτων (Internet of Things).
Ali Mohammad Saghiri, Monireh Vahdati, Kamran Gholizadeh HamlAbadi, Mohammad Reza Meybodi · 6 authors
Internet of Things, cognitive systems, and blockchain technology are three fields which have created numerous revolutions in software development. It seems that a combination among these fields may results in emerging a high potential and interesting field. Therefore, in this paper, we propose a framework for Internet of Things based on cognitive systems and blockchain technology. To the best of our knowledge, there is no framework for Internet of Things based on cognitive systems and blockchain. In order to study the applicability of the proposed framework, a recommender system based on the proposed framework is suggested. Since the proposed framework is novel, the suggested recommender system is novel. The suggested recommender system is compared with the existing recommender systems. The results show that the suggested recommender system has several benefits which are not available in the existing recommender systems.
Building blockchain-oriented applications forces developers to rethink the architecture of their software from the ground up. The use of blockchain technology poses multiple challenges as the software is operated in a decentralized, trustless, transparent and tamper-proof environment. When building decentralized apps the developers need to deal with blockchain properties such as decentralization, a certain delay in the execution of function calls of distributed code contracts and particularly need to consider how users interact with their application. We surveyed several existing decentralized apps and examined their architecture to identify multiple reoccurring architectural patterns, each with different implications regarding the trust, user experience and security. As building blockchain-oriented applications is gaining importance, models, tools and methods for blockchain-oriented software engineering have to be developed. This paper gives a first hint towards architectural patterns for blockchain-based applications and motivates why it is important to consider how the user interacts with the decentralized apps.
Igor D. Alvarenga, Gabriel Antonio F. Rebello, Otto Carlos M. B. Duarte
The integration of network function visualization (NFV) and service function chaining (SFC) adds intelligence to the core of the network. The programmability of the network core, however, raises new vulnerabilities and increases the number of victims, since a simple modification in the core can affect multiple network users. Thus, the provision of secure virtual network service functions (VNFs) is mandatory to guarantee a correct chaining of network functions. This paper proposes a blockchain-based architecture for secure management, configuration and migration of VNFs, which ensures: (i) immutability, non-repudiation, and auditability of the configuration update history; (ii) integrity and consistency of stored information; and (iii) the anonymity of VNFs, tenants, and configuration information. Furthermore, the proposed architecture guarantees the secure update and migration of configurations at the core of the network. A prototype of the proposed architecture using the Open Platform for NFV (OPNFV) indicates parameter trade-offs and performance bottlenecks.
Several popular cryptocurrencies incorporate privacy features that "mix" real transactions with cover traffic in order to obfuscate the public transaction graph. The underlying protocols, which include CryptoNote and Monero's RingCT, work by first identifying a real transaction output (TXO), sampling a number of cover outputs, and transmitting the entire resulting set to verifiers, along with a zero knowledge (or WI) proof that hides the identity of the real transaction. Unfortunately, many of these schemes suffer from a practical limitation: the description of the combined input set grows linearly with size of the anonymity set. In this work we propose a simple technique for efficiently sampling cover traffic from a finite (and public) set of known values, while deriving a compact description of the resulting transaction set. This technique, which is based on programmable hash functions, allows us to dramatically reduce transaction bandwidth when large cover sets are used.We refer to our construction as a recoverable sampling scheme, and note that it may be of independent interest for other privacy applications. We present formal security definitions; prove our constructions secure; and show how these constructions can be integrated with various currencies and different cover sampling distributions.
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Robert Norvill, Beltrán Borja Fiz Pontiveros, Radu State, Andréa Cullen
In this work we present E-EVM, a tool that emulates and visualises the execution of smart contracts on the Ethereum Virtual Machine. By working with the readily available bytecode of smart contracts we are able to display the program's control flow graph, opcodes and stack for each step of contract execution. This tool is designed to aid the user's understanding of the Etheruem Virtual Machine as well as aid the analysis of any given smart contract. As such, it functions as both an analysis and a learning tool. It allows the user to view the code in each block of a smart contract and follow possible control flow branches. It is able to detect loops and suggest optimisation candidates. It is possible to step through a contract one opcode at a time. E-EVM achieved an average of 85.6% code coverage when tested.
Wazen M. Shbair, Mathis Steichen, Jérôme François, Radu State
Conducting experiments to evaluate blockchain applications is a challenging task for developers, because there is a range of configuration parameters that control blockchain environment. Many public testnets (e.g. Rinkeby Ethereum) can be used for testing, however, we cannot adjust their parameters (e.g. Gas limit, Mining difficulty) to further the understanding of the application in question and of the employed blockchain. This paper proposes an easy to use orchestration framework over the Grid'5000 platform. Grid'5000 is a highly reconfigurable and controllable large-scale testbed. We developed a tool that facilitates nodes reservation, deployment and blockchain configuration over the Grid'5000 platform. In addition, our tool can fine-tune blockchain and network parameters before and between experiments. The proposed framework offers insights for private and consortium blockchain developers to identify performance bottlenecks and to assess the behavior of their applications in different circumstances.
A distributed extended information filter-based interacting multiple model estimator with unbiased mixing is proposed for satellite launch vehicle tracking. In this problem, multiple heterogeneous sensors such as radars, telemetry systems receiving onboard Global Positioning System—inertial navigation system data, and electro-optical targeting systems are used. The extended information filter is used for nonlinear estimation dealing with ballistic model and spherical coordinate observation. The multiple Markov switching models comprise thrusting and coasting modes having different state vector dimensions for the launch vehicle. To effectively combine both state vectors, an unbiased mixing technique is applied and then the distributed extended information filter integrates local states and information matrix contributions. Hence, the proposed algorithm takes into account both heterogeneity of tracking sensors and multiplicity of vehicle’s dynamic model. We prove the superiority of the proposed algorithm by conducting Monte Carlo simulation with nominal trajectory data of Korea Space Launch Vehicle-1. Comparative simulation results demonstrate that the performance of the proposed method has been improved in vehicle’s position root mean square error.
The Netlab project is part of an ongoing effort in image informatics that began in early 1985. This early work resulted in the development of the first digital histology atlas system, which was presented at a NASA conference in 1987. That system used a technology called MetaMAP to make every pixel of the image an independently‐addressable hotspot, linkable to histology knowledge data relating to the cell or structure at that location in the image. The MetaMAP system was then applied to larger anatomy imaging projects, first in the Visible Embryo Project, at UCSF, in 1994, then in the Muritech Atlas of Mouse Development, in 1996, and the Eolas AnatLab project in 1998 and later. In the AnatLab system, MetaMAP allowed the creation of over 800,000 3D anatomical annotations to be made on the image data from the Visible Human Project. The scale of that effort exposed the extreme difficulty involved in validating this kind of data, even when the annotators were trained anatomy students supervised by a professor. The Netlab system is an attempt to lay the groundwork for both building virtual microscopy resources of unlimited scale, and leveraging the power of crowdsourcing to facilitate detailed and validated annotation of the microscopic image data accessible through the system. The Netlab client software allows users to access Aperio‐scanned slide image data streamed in real time over the cloud from the Netlab servers to either a Web browser or a mobile app. Users can pan and zoom in and out across the magnification ranges typical of microscopes in the lab, and can place textual annotations at any locations on any slides in the collection. Each annotation can be classified as private, group or public. Any user with access permission to view another user's annotation can validate that annotation. Each validation is assigned a weight based upon the role of the validator (peer or professor, for example). Group moderators (e.g., professors) can set thresholds for validation. Annotations above the threshold have a “verified valid” icon displayed when viewed. Future work will focus on both expanding the image collection and the development of a more automated validation system, using an approach inspired by the proof‐of‐stake distributed consensus algorithms currently popular in the blockchain technology field. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
Mengting Liu, F. Richard Yu, Yinglei Teng, Victor C. M. Leung · 5 authors
Blockchain is widely deemed as a key enabling technology of current digital currency. However, the application of blockchain to wireless mobile networks is challenged by a computational difficult problem called proof-of-work puzzle. Accordingly, mobile edge computing (MEC) appears to be a promising solution by offloading the computation-intensive mining tasks to nearby edge computing nodes. Meanwhile, caching is also popular due to its capability in handling the ever-increasing Internet traffic. In this paper, we study computation offloading and content caching in wireless blockchain networks with MEC. Specifically, offloading mode selection (offloaded to a nearby access point (AP) or a group of device-to-device (D2D) users) and caching strategy (whether to cache the requested content and computation results or not) are jointly investigated and formulated as an optimization problem. Further, an alternating direction method of multipliers (ADMM) based algorithm is proposed to solve the optimization problem in a distributed way. Finally, the effectiveness of the proposed algorithm is demonstrated by simulation results with different system parameters.
Information security is the key to the development of modern Internet technology. The distributed mechanism, decentralized mechanism, password mechanism and scripted mechanism of the Blockchain present a completely new perspective for the development of Internet information security technology. The Blockchain technology redefines the storage and dissemination methods of the information in the network. Neither participant needs to know each other, and nor does it require third-party certification bodies to participate. It records, transmits and stores transferring activities of the information value by distributed technology, ensures that data is not tampered and forged based on an asymmetric cryptographic algorithm, enables all participants reached a consensus on the status of blockchain data information. And from the current industry research on blockchain technology, it expounds the application of blockchain technology in identity authentication, data protection and network security. The Blockchain technology will be a great driving force in the process of information security technology change, and will have a far-reaching impact on the expansion of information security.
Bitcoin, the world’s most valued cryptocurrency, uses a network of computers across the globe to create an immutable transaction record on a public ledger known as the blockchain. The blockchain consists of a series of timestamped blocks, where each block contains a series of transactions selected for inclusion in the block, generally based on how high of a fee the transaction allocates to the party responsible for confirming the transaction. Estimating an appropriate fee for Bitcoin transactions is a challenge for many transacting parties using Bitcoin as a digital currency. This work aims to help Bitcoin users save funds in their transaction fees when building multisig transactions by providing fee estimates that referenced the current state of the unconfirmed transaction pool using the perceptron machine learning classification algorithm. 4
The distributed ledger technology presents a very innovative and secure way of managing transactions online. Hailed as one of the greatest inventions after the Internet, blockchain is set to pioneer changes in the way businesses are conducted today through its promise of secure, tamper-proof, peer-to-peer decentralized networks with distributed consensus. These fundamental features built into the very fabric bring in a host of additional dimensions and present greater challenges in their testing. Not only are the technological changes significant, but also significant are changes from a business standpoint. A new wave of blockchain oriented software development is emerging at an unprecedented rate. This places an additional responsibility on the Quality Assurance teams to deliver first-time quality while minimizing the impact of testing on the teams delivery. This paper highlights the challenges currently faced in testing such applications. It also acknowledges the need to devise specialized tools and techniques for blockchain oriented software testing in order to ensure high standards of quality.
Traceability of ICs is important for verifying provenance. We present a novel IC traceability scheme based on blockchain. A blockchain is an immutable public record that maintains a continuously-growing list of data records secured from tampering and revision. In the proposed scheme, IC ownership transfer information is recorded and archived in a blockchain. This safe, verifiable method prevents any party from altering or challenging the legitimacy of the information being exchanged. However, we also need to establish correspondence between a record in a public database and the physical device, in an unclonable way. We propose an embedded physically unclonable function (PUF) to establish this correspondence The blockchain ensures the legitimacy of an IC's current owner, while the PUF safeguards against IC counterfeiting and tampering. Our proposed solution combines hardware and software protocols to let supply chain participants authenticate, track, trace, analyze, and provision chips during their entire life cycle.
Physical Unclonable Functions (PUFs) and Hardware Security
Integrated Circuits and Semiconductor Failure Analysis
The Blockchain paradigm provides a popular mechanism for establishing trust and consensus in distributed environments. While Blockchain technology is currently primarily deployed in crypto-currency systems like Bitcoin, the concept is also expected to emerge as a key component of the Internet-of-Things (IoT), enabling novel applications in digital health, smart energy, asset tracking and smart transportation. As Blockchain networks evolve to industrial deployments with large numbers of geographically distributed nodes, the block transfer and processing delays arise as a critical issue which may create greater potential for forks and vulnerability to adversarial attacks. Motivated by these issues, we develop stochastic network models to capture the Blockchain evolution and dynamics and analyze the impact of the block dissemination delay and hashing power of the member nodes on Blockchain performance in terms of the overall block generation rate and required computational power for launching a successful attack. The results provide useful insight in crucial design issues, e.g., how to adjust the `difficulty-of-work' in the presence of delay so as to achieve a target block generation rate or appropriate level of immunity from adversarial attacks. We employ a combination of analytical calculations and simulation experiments to investigate both stationary and transient performance features, and demonstrate close agreement with measurements on a wide-area network testbed running the Ethereum protocol.
Kumar Bhaskaran, Peter Ilfrich, Dain Liffman, Christian Vecchiola · 12 authors
Blockchains are designed for trustworthy and transparent execution of transactions involving multiple parties. An important class of applications requires data to be shared selectively among mutually anonymous transacting peers while retaining the tamper-resistant evidentiary and validation features of a blockchain. KYC validations of corporate customers by banks is one example, where both banks and customers benefit from sharing process and data on a blockchain network. However, sharing of confidential KYC data must be authorized by customers, and a bank-customer relationship must be kept secret from other banks in the network. In this paper, we describe the design and implementation of a smart contract for consent-driven and double-blind data sharing on the Hyperledger Fabric blockchain platform. We show how a KYC application was built around this model to address the needs of the banks while meeting regulatory requirements.
Distributed processing and control are critical to supports distributed intelligence and autonomy of multi-degree-of-freedom motion systems. Measurements and fusion of spatiotemporal physical quantities imply data-intensive computing and spatial distribution of computing resources to enable control and processing of large data sets from image and inertial sensors. We examine distributed and asynchronous processing nodes which process information independently deriving partial solutions. There are multiple sensing-and-processing nodes in each individual agent. Each node comprises solid-state or MEMS multi-degree-of-freedom sensors with ASICs which process and fuse data. On-node computing supports distributed processing. Adaptive bottom-up organization ensures data aggregation and data management with operation on sub-samples or hashed sets of large source datasets. Cooperative distributed processing is essential in centralized, decentralized and behavioral coordination. In the centralized organization, a central processor may not ensure adequacy. A network of semi-autonomous on-device processing sensors may interact to solve specific tasks and validate solutions. Problem allocation, partitioning, coordination and other tasks are implemented using software-and hardware-supported algorithms and protocols. This paper contributes to design of next generation of systems with distributed multi-node processing capabilities.
Target Tracking and Data Fusion in Sensor Networks
With the success of Bitcoin, the technique behind it, Blockchain, is catching massive attention recently. Blockchain is a collection of several techniques like cryptology, P2P and distributed consensus protocol. The main idea of Blockchain is that nodes in the network keep the same distributed ledger. Because of this immutable ledger, a trusted bridge is built among parties without fully trust. Blockchain can be used in variety of areas, especially in financial fields, like supply chain management, cross-border payment and global bank settlement. Meanwhile, we can observe that mobile network is growing rapidly and nibbling the PC market. However, the current public Blockchain applications like Bitcoin or Ethereum require the nodes to store the whole ledger which exceeds the capacity of the mobile devices. Thus, we need to develop a blockchain platform to support mobile devices. In this demo, we introduce Jupiter, a mobile-based Blockchain platform which provides a novel concept called consensus unit (CU) to alleviate the storage problem of mobile. We present the system architecture and demonstrate several CU scenarios via Jupiter.
Roman Matzutt, Martin Henze, Jan Henrik Ziegeldorf, Jens Hiller · 5 authors
Since the introduction of Bitcoin in 2008, blockchain systems have seen an enormous increase in adoption. By providing a persistent, distributed, and append-only ledger, blockchains enable numerous applications such as distributed consensus, robustness against equivocation, and smart contracts. However, recent studies show that blockchain systems such as Bitcoin can be (mis) used to store arbitrary content. This has already been used to store arguably objectionable content on Bitcoin's blockchain. Already single instances of clearly objectionable or even illegal content can put the whole system at risk by making its node operators culpable. To overcome this imminent risk, we survey and discuss the design space of countermeasures against the insertion of such objectionable content. Our analysis shows a wide spectrum of potential countermeasures, which are often combinable for increased efficiency. First, we investigate special-purpose content detectors as an ad hoc mitigation. As they turn out to be easily evadable, we also investigate content-agnostic countermeasures. We find that mandatory minimum fees as well as mitigation of transaction manipulability via identifier commitments significantly raise the bar for inserting harmful content into a blockchain.
Blockchain Technology Applications and Security
FinTech, Crowdfunding, Digital Finance
Advanced Steganography and Watermarking Techniques
The current web 2.0 is about connecting people. In which the social media platforms were invented, and the concentration of development was focused on the application layer. There are different approaches to think about web 3.0, some; would say the future is when we have a semantic web others would argue that the future is the virtual web. In this paper, we will talk about another direction to think about the future web called the decentralized web. To enhance the web, we should be concerned with solving the problems that we have and the problems that these platforms have created. The decentralized web is focused on developing protocols and the underlying technologies that are not noticed by end users. This paper gives an overview of the challenges in the current web 2.0. Describes the decentralized web, and what are the technologies that are in development now.
Douglas McWilliams, Cristian Niculescu-Marcu, Beatriz das Neves Abreu Marques da Cruz
Long Finance's Distributed Futures research programme is pleased to announce the publication of the report, “The Economic Impact Of Smart Ledgers On World Trade”, the latest in a series of exciting projects in the programme. The report, sponsored by the Cardano Foundation, came as a result of the the Worshipful Company of World Traders and the Distributed Futures' interest in quantifying the potential impact of Smart Ledger technology on international trade. Written by Douglas McWilliams, Cristian Niculescu-Marcu, and Beatriz Cruz from the Centre for Economics and Business Research (Cebr), it includes a Foreword by Michael Parsons FCA, Chairman of Cardano Foundation, and a Preface by Professor Michael Mainelli, Executive Chairman of Z/Yen Group.
The report features a description of the econometric approach that maps trade frictions that Smart Ledger technology might be able to offset, especially in the realm of non-tariff and bureaucratic barriers to trade. The authors draw the following conclusions:
Smart Ledger technology could boost world trade in goods by at least $35 billion dollars per annum.
The cost of importing a single container could, therefore, be reduced by around $46, by simplifying procedures.
These potential benefits are driven by a 2.5% cost claw-back assumption, supported by case studies on previous technological advancements in trade. One such case study is containerization, where the cost savings have been calculated to be in the range of 20%.
If reduced uncertainty is, also, taken into account, using option pricing theory, the potential gains become even larger, with a potential monthly net cost saving of $172 million (or, approximately, $2 billion per annum).
This would boost world GDP by $10 to $20 billion and could, potentially, add between 450,000 and 900,000 to the worldwide demand for labor, boosting wages and living standards worldwide. The World Bank estimates that 10.7% of the world’s population still lives in extreme poverty, with an income below $1.90 a day (2011 prices).
The report also includes the results of a global survey of 247 contract and commercial managers, focusing on the respondents' awareness and use of Smart Ledgers, the importance they attach to various aspects, and the areas of ‘pain’ that could be relieved by the adoption of Smart Ledger technology. There are some truly insightful results.
Smart Ledgers are based on a combination of mutual distributed ledgers (multi-organisational databases with a super audit trail) with embedded programming and sensing, thus permitting semi-intelligent, autonomous transactions. Smart Ledgers are touted as a technology for fair play in a globalized world. There are numerous projects building trade systems using this technology with announcements from governments, shipping firms, large IT firms, and the like.
As Michael Mainelli wrote in his Preface to the report: Trade reaps economic benefits from specialization and comparative advantage, creates prosperity, distributes success and wealth, and collectively enriches all of our societies and communities. Hopefully, knowing the scale of relative benefits can help speed adoption of some boring technology – ‘multi-organisational databases with a super audit trail’ - for the benefit of all of us.
Z/Yen and Long Finance would like to acknowledge the significant contribution of the Worshipful Company of World Traders, Cardano Foundation, IACCM, the City of London Corporation, and the Centre for Economics and Business Research.