Titel: Kan Bitcoin bli framtidens betalningsmedel i utvecklingsländer? Författare: Isak Bengtsson och Gustaf Starbrant Bakgrund och problemdiskussion: I utvecklingsländer finns det betydande grupper människor som inte har tillgång till ett fungerande bankkonto. Detta skapar problem i form av finansiellt utanförskap för vissa befolkningsgrupper. Bitcoin är en digital valuta som alla människor i teorin skulle kunna få tillgång till, med en mobiltelefon med nätverksuppkoppling som enda krav. Därigenom skulle fler människor i utvecklingsländer ha tillgång till fungerande betalningsmöjligheter och inte utsättas för finansiellt utanförskap. Forskningsfråga: Vilka möjligheter samt risker finns avseende att införa Bitcoin som betalningsmedel i utvecklingsländer? Syfte: Syftet med studien är att undersöka och analysera möjligheter samt risker avseende införandet av Bitcoin som betalningsmedel i utvecklingsländer. Metod: Genom en abduktiv ansats och en kvalitativ metodik har vi sammanfattat resonemang, argument och forskning kring Bitcoin. Material har samlats in genom tidigare forskning och semistrukturerade intervjuer. Referensram: Bitcoin och blockkedjetekniken presenteras men även Bitcoin som valuta och dess möjligheter och risker. Teorierna förtroendeteori och penningteori belyses också. Dessa utgör grundstenar och används som ett analysverktyg i uppsatsen. Empiri: Vårt empiriska undersökningsområde innefattar personer med kunskap om Bitcoin och dess underliggande teknik, blockkedjetekniken. Insamlandet av det empiriska materialet skedde genom sex semistrukturerade intervjuer. Analys och slutsatser: Bitcoin är den största digitala valutan i dagsläget och erbjuder stora möjligheter generellt. Det finns dock begränsningar, till exempel skalningsproblematik och deflation, som hade gjort det svårt för en implementering som valuta i utvecklingsländer. Däremot innehar blockkedjetekniken stor potential att förändra infrastrukturen för betalningar. Nyckelord: Betalningsmedel, Bitcoin, blockkedjetekniken, digital valuta, möjligheter, risker, utvecklingsländer
Journal of Anthropology and Archaeology is a peer-reviewed international journal, which publishes original papers promoting theoretical, methodological and empirical developments in the discipline of socio-cultural anthropology.
Blockchain is making headlines due to it promises to provide a decentralized, transparent, tamper-resistant, traceable and verifiable historical transaction records that can resist faults of any single node. According to the latest data from State of the Dapps, developers have currently released 3,717 Decentralized Applications (DApps), only three have an average of more than 10,000 daily active users. Most of the real-world DApps exercise little of their potential power. The key reason is that the current permissioned blockchain systems suffer from poor performance and lack of confidentiality. To address this issue, we present Hybridchain, a system that combines blockchain with Trusted Execution Environment (TEE). Hybridchain decouples computation from consensus and adopts hierarchical network to minimize the computational burden and latency of on-chain execution by performing most of the heavy-weight computation off-chain. Hybridchain leverages secure communication protocols to enable each participant to share transaction data in a secure way. To mitigate the small enclave memory restriction of TEE, Hybridchain extends the enclave memory that allows blockchain applications running in TEE to securely store transaction records to the whole key-value storage codes placed outside of TEE. Analysis and experiments of sealed-bid auction show that Hybridchain can support confidentiality-preserving along with high performance.
The article examines the mechanisms of financing education in general and vocational training, in particular, in the process of decentralization and reform of the administrative-territorial structure of the country.
This study proposes a method to enhance cryptocurrency portfolios constructed by forecast models. This study forecasts returns on four liquid cryptocurrencies (Bitcoin, Litecoin, Ripple, and Dash) and determines the weights on the cryptocurrencies based upon a dynamic allocation framework. We assess the performances of the portfolios using the performance fee measure. Our results present that the proposed portfolios outperform the benchmark portfolio with the conventional level of the risk aversion parameter. The economic gain for an investor is equivalent to 12% per week. The economic gain is sensitive to a change in the risk aversion parameter, which contrasts with the studies of exchange rates which is due to the high volatility on the cryptocurrencies. Our predictors are related to the price momentum effects and they outperform widely used network factors.
The use of digital documents is exploding around the world due to the improvement of productivity and the convenience of access and backup of data.Usually, digital documents are managed by a document management system (DMS) which provides access control of the documents with access permission (e.g., password or account).However, when a user who has permission for the documents can directly access the digital document, it can occur a serious security problem.For example, when a malicious attacker gets access permission of a digital document, the document is able to be leaked.In addition, when a user who has authority behaves maliciously for his own benefit, the digital document can be easily falsified by the user.To handle these issues, we propose a new digital document management system for the security of digital documents which distributes the access permissions of the digital document.The proposed system encrypts a digital document with a key and stores the encrypted document into Interplanetary File System(IPFS).In addition, to distribute access permission of the digital document, it manages the key via Shamir's secret sharing scheme and blockchain.We implement our proposed system using Golang on Linux and evaluate the system on local IPFS and Ethereum testnet.The experimental results show that the proposed system provides high security of the digital document with minor performance overhead compared with the existing system.
Bitcoin has been described as digital gold. Bitcoin is exactly like gold except when it isn’t. Over millennia, gold has gained a questionable reputation as an inflation hedge, a store of value and a safe haven. Gold’s price can arguably be decomposed into a “golden constant” fair price and a fair price deviation. Bitcoin has no track record as an inflation hedge, a store of value and a safe haven. Bitcoin’s price can arguably be decomposed into a questionable “bitcoin network” fair price and a fair price deviation. Both bitcoin and gold are about 50% above their “fair prices”.
Guglielmo Maria Caporale, Alex Plastun, Viktor Oliinyk
This paper investigates the relationship between Bitcoin returns and the frequency of daily abnormal returns over the period from June 2013 to February 2020 using a number of regression techniques and model specifications including standard OLS, weighted least squares (WLS), ARMA and ARMAX models, quantile regressions, Logit and Probit regressions, piecewise linear regressions, and non-linear regressions. Both the in sample and out-of-sample performance of the various models are compared by means of appropriate selection criteria and statistical tests. These suggest that, on the whole, the piecewise linear models are the best, but in terms of forecasting accuracy they are outperformed by a model that combines the top five to produce “consensus” forecasts. The finding that there exist price patterns that can be exploited to predict future price movements and design profitable trading strategies is of interest both to academics (since it represents evidence against the EMH) and to practitioners (who can use this information for their investment decisions).
There is a distinct lack of democratic governance in our contemporary era.In this paper I develop a mechanism to overcome this democratic deficit.'The Cryptostate' is an amalgamation of primordial democratic theory and recent technological advancements.By combining democratic principles with distributed ledger technology, we can create a decentralized, transparent, governance framework in which various groups-societies, ethnicities, or nations-can communicate, coordinate, and enfranchise all affected members.Never before in human history has it been technologically feasible to create such an entity.In this article, I demonstrate that not only can such a state exist, but that in the face of our ongoing technological and global upheaval, it must.
Priyanka Padki, Riya Anna Sunny, N. Ramya, S Aishwarya · 5 authors
In this paper we are proposing a blockchain based video surveillance system. The proposed framework includes a collection of blockchain, with trusted internal managers. The video metadata is registered on the blockchain's distributed ledger thus preventing the possibility of data forgery. Proposed designs encrypt and collects footages, generates a license and exports video inside the blockchain. Because the blockchain's private database manages the decryption key for the film, the internal manager does not leak it without the consent of the owner. Also, the admin can securely maintain and send the footages by sending it to the DRM-applied video player the license created in the blockchain.
Open access
Advanced Steganography and Watermarking Techniques
Im Rahmen des Deutsch-Österreichischen Forschungsprojekts NutriSafe (Sicherheit in der Lebensmittelproduktion und -logistik durch die Distributed-Ledger-Technologie) wurde eine Analyse zur Identifikation von relevanten Schwachstellen und Angriffsketten in Wertschöpfungsketten von Lebensmitteln durchgeführt. Die vorliegende Arbeit beschreibt die Analyse der IT-Infrastrukturen von fiktiven, aber der Realität nachempfundenen Akteuren der Wertschöpfungskette, basierend auf einem der Szenarien des NutriSafe-Projekts. Ergebnisse sind Beziehungen von Gefährdungen zu IT-Infrastrukturen und Modelle von Angriffsketten in Form von Attack Trees.
Blockchain technology has recently obtained widespread attention. And it is being regarded as potentially even more disruptive than the Internet, whose usage includes large areas of applications ranging from crypto currency, financial services, reputation system, Internet of Things, sharing economy to public and social services. The existing works of blockchain primarily are focused on key components and potential applications. However, in the existing blockchain systems, the waiting time of transactions is too long. Furthermore, it may produce serious consequences because many important transactions are not handled timely. To solve the problem, in the paper, the blockchain Queuing model with non-preemptive limited-priority is established, which considers the different transactions having different priority when being mined. There are two classes of transactions in the model, one is high-priority transaction with pay or with prior interest, the other is low-priority transaction without pay or without prior interest. And high-priority transactions can be mined preferentially when mining process is not occupied. If low-priority transaction is being mined, the arriving high-priority transaction will wait for the mining accomplishment. Through the analysis of the model, we compute average waiting time, average staying time and average length of queue. From simulation of the model, we find that transactions with pay or with prior interest and increase service rate of mining are effective for reducing waiting time. Besides, the two factors mutually reinforce to shorten waiting time. Finally, we conclude this paper and point out the direction of future research.
In this thesis, we present novel methods for verifying, implementing and specifying protocols. In particular, we focus properties modeling data protection and the protection of privacy. In the first part of the thesis, the author introduces protocol verification and presents a model for verification that encompasses so-called Zero-Knowledge (ZK) proofs. These ZK proofs are a cryptographic primitive that is particularly suited for hiding information and hence serves the protection of privacy. The here presented model gives a list of criteria which allows the transfer of verification results from the model to the implementation if the criteria are met by the implementation. In particular, the criteria are less demanding than the ones of previous work regarding ZK proofs. The second part of the thesis contributes to the area of protocol implementations. Hereby, ZK proofs are used in order to improve multi-party computations. The third and last part of the thesis explains a novel approach for specifying data protection policies. Instead of relying on policies, this approach relies on actual legislation. The advantage of relying on legislation is that often a fair balancing is introduced which is typically not contained in regulations or policies.
In recent years, cryptocurrencies implemented on top of Blockchains became very popular, with Bitcoin as the most prominent example. However, novel Blockchain-based platforms such as Ethereum also support distributed applications beyond cryptocurrencies through so-called smart contracts. Technically, smart contracts are programs, whose code and execution state is stored in the Blockchain, inherently featuring the ability to transfer (electronic) money during their execution. In this Bachelor thesis, we investigate how smart contracts can be used to implement a distributed crowdsensing application for tracking mobile objects by a crowd of privately owned mobile devices. Such a system could be used, for instance, to nd lost or stolen objects, such as keys, vehicles (cars, bicycles, . . . ), or pets tagged with short-range radio transmitters implemented using readily available Bluetooth or RFID technology. These objects can then be detected by smartphones of private users in the vicinity of the object, effectively implementing a huge sensor network covering many parts of the world without any upfront investments by a central entity. Although highly attractive, implementing a crowdsensing application on top of a Blockchain platform such as Ethereum comes with several challenges. First of all, users need incentives to participate in searching for mobile objects. A natural incentive is a monetary reward that participants automatically receive through the smart contract when reporting sightings (timestamped positions) of wanted objects. However, this directly brings up the problem of malicious participants (attackers) who try to get the reward without actually executing the work of searching for the object by simply reporting fake positions. Therefore, one major goal of this Bachelor thesis is to counter such attacks by proposing effective counter-measures, and implementing and evaluating them for the Ethereum platform. In detail, we propose a basic reputation-based approach for detecting fake positions which judges each sighting made by a mobile devices according to the reputation of that device, implemented by a smart contract. Furthermore, advanced attacks are identified compromising the basic reputation-based approach and effective counter-measures to these advanced attacks are proposed. Identified advanced attacks include reputation farming, where the attacker tries to aggregate reputation first before launching the attack, and the so-called copycat attack, where the attacker simply copies already submitted valid sightings form honest participants, making his fake positions indistinguishable from valid positions. Our evaluations analyses the monetary cost of executing smart contracts with and without our security mechanisms. The results show that the overhead included by our reputation-based approach is at maximum 45% of the cost of a smart contract without implemented security mechanisms.
Carlos Roberto López Zambrano, Mario Camberos Castro
Bitcoin is part of the so-called crypto-currencies and can be defined as a universal decentralized public electronic payment system, based on Blockchain technology. The problem it faces is trust in its use; therefore, the objective of this research is to analyze the factors that influence the adoption and use of Bitcoin in Mexico. For this purpose, the UTAUT2 model integrated with the trust variable is used. The model was empirically tested by applying a survey of 106 questionnaires, under the partial least square’s method, with structural equation models (PLS-SEM). The main results indicate that performance expectation, hedonistic motivation, habit and its decentralization, are the main factors that influence confidence for the adoption and use of Bitcoin. The results illustrate to companies and any interested party the advantages of using Bitcoin.
Bitcoin is a well known cryptocurrency that has existed for over a decade. We examine the historical cross-market dynamic relationships among four important Bitcoin cryptocurrency markets at a pivotal point in cryptocurrency acceptance among markets and the public. We pay particular attention to cross-market relations during the introduction of a new, competing Bitcoin exchange, Bitfinex, and the subsequent demise of the once-prominent Bitcoin exchange, Mt. Gox. Our findings show that Bitfinex's introduction led to a shifting of trading activity from the once popular Mt. Gox exchange to other exchanges. Mt. Gox's loss of trading activity caused price distortions in all Bitcoin markets under study. In addition, cross-market relationships became less efficient while Mt. Gox experienced its death throes. Our study provides evidence that (1) Bitcoin markets are susceptible to volume losses to rival exchanges, (2) shifting trading activity is also associated with price distortions mainly originating from the suffering exchange, and (3) Bitcoin cross-market dynamics are resilient and, ultimately, self-healing from shocks, strengthening Bitcoin's long-term viability.
In this thesis, our objective is to study the relationship between transaction price and volume in the BTC/USD Coinbase exchange. In the second chapter, we develop a consecutive CUSUM algorithm to detect instantaneous changes in the arrival rate of market orders. We begin by estimating a baseline rate using the assumption of a local time-homogeneous Poisson process. Our observations lead us to reject the plausibility of a time-homogeneous Poisson model on a more global scale by using a chi squared test. We thus proceed to use CUSUM-based alarms to detect consecutive upward and downward changes in the arrival rate of market orders. In the third chapter we identify active periods from the number of consecutive upward CUSUM alarms, leading to the classification of active versus inactive periods. Finally we use One-Way ANOVA to assess the level effect on price swings for periods classified as containing at least two or three consecutive CUSUM up alarms. We show that in these active periods, price swings are significantly larger than in inactive periods.
Le Su, Dinil Mon Divakaran, Sze Ling Yeo, Jiqiang Lu · 5 authors
With the rapid deployment of IoT devices, there is an increasing concern on the security and privacy of the devices. We are now witnessing newer and higher intensity attacks that exploit IoT devices. Although security-by-design is important and necessary, the effectiveness and sustainability of the buildin security defense may still be questionable. This has created new opportunities for third-party security service providers to enter the market. In this work, we leverage the distributed ledger technology (DLT) to propose a solution for distributing IoT security functions. We design the system architecture and describe the different types of operations to be executed. Our system also allows for reputation scoring that further adds credibility to the security functions distributed in the network.
The three cutting-edge technologies virtual reality, blockchain, and 5G have increasingly attracted public attention. While virtual reality became a popular concept in the 1990s, recent technological advances and decreased costs have created a resurgence in the technology. With significant funding and early adoption, blockchain and 5G have begun to make their mark on the world. Each technology alone may disrupt business and society, but, together, they provide multiple opportunities. In this paper, we summarize a 2018 Association for Information Systems Americas Conference on Information Systems (AMCIS) panel session with IS researchers and industry practitioners that tackled important topics related to these technologies. In particular, the panel made the case for IS research that focuses on topics that emerge when these technologies intersect. Each panelist presented their perspectives based on their experience and knowledge along with current issues and future directions. This topic has significant business implications as practitioners continue to note their advancements and develop strategies to adapt in a rapidly changing environment. The topic also has implications for future research as these technologies continue to become more prevalent.