Money is a widely accepted commodity allowing to determine the economic value of purchased goods and services and to make payments. Over the centuries, "money" has been constantly evolving. In recent times, following dynamic development of various forms of e-business, dematerialized money has emerged. However, in constantly changing conditions it is very difficult to grasp the essence of the so called e-money or cryptocurrencies. The paper tries to define Bitcoin, one of the most recognizable cryptocurrencies, and answer the question whether investing in cryptocurrencies is a serious business or a mere gambling. In search for the answers, the author reviews literature on the topic and conducts his own risk analysis based on Value at Risk measure, of selected traditional currencies and Bitcoin. The results of the analysis unambiguously show that investments in Bitcoin are burdened with definitely much higher risk. Furthermore, conclusions of the considerations clearly show that despite growing popularity of cryptocurrencies they do not fulfill the definition of both electronic money or money in general. The paper attempts to discuss selected issues related to Bitcoin cryptocurrencies from the monetary point of view but also with respect to restrictions of Bitcoin as a means of payment, investments in Bitcoin and risk assessment.
How promising is Bitcoin as a currency? This paper discusses four claims on the advantages of Bitcoin: a more stable currency than state-backed ones; a secure and efficient payment system; a credible alternative to the central management of money; and a better protection of transaction privacy. We discuss these arguments by relating them to their philosophical roots in libertarian and neoliberal theories, and assess whether Bitcoin can effectively meet these expectations. We conclude that despite its advocates' enthusiasm, there are good reasons to doubt that Bitcoin can fulfill its promises and act as a functioning currency, rather than as a mere speculative asset.
The revolution of Internet of Things (IoT) devices and wearable technology has opened up great possibilities in remote patient monitoring. To streamline the diagnosis and treatment process, healthcare professionals are now adopting the wearable technology. However, these technologies also pose grave privacy risks and security concerns about the transfer and the logging of data transactions. One solution to protect privacy in healthcare is the use of blockchain technology. However, one of the primary problems with blockchain is its highly limited scalability. In this work here, we propose the utilization of a blockchain based protocol to provide secure management and analysis of data. In this paper we use recently introduced PoW based protocol GHOSTDAG, that generalizes Satoshi's blockchain to a direct acyclic graph of blocks (blockDAG) and provides high throughput while also avoiding the security-scalability problem. We use two blockchains based on the original GHOSTDAG protocol, one that is private and one that is public. Using a private blockchain, we create a system where we use smart contracts to analyze patient health data. If the smart contract for any reason issues an alert for an abnormal reading then the system makes the record of that event to the public blockchain. This would resolve the privacy and security vulnerabilities associated with remote patient monitoring and also the limited scalability problem of Satoshi's original blockchain.
Bitcoin has recently been labelled as a “dangerous speculative bubble†by Nobel Prize-winning economists Joseph Stiglitz and Robert Shiller, as the Bitcoin's market value now exceeds the GDP of over 130 countries. In this study, the multifractality and efficiency of the Bitcoin price index are tested, using a nonlinear data analysis technique called the multifractal detrended fluctuation analysis (MF-DFA). In addition, we assess the time-variations in the market efficiency level through using a rolling-window framework. Our evidence shows that the efficiency of the Bitcoin market changes over time and this market seems to be more efficient during downward than upward periods. We also find that Bitcoin is marked by a persistent long memory phenomenon in its short- term components, which could be interpreted as a possible speculation by investors.
One of the defining features of a cryptocurrency is that its ledger, containing all transactions that have ever taken place, is globally visible. As one consequence of this degree of transparency, a long line of recent research has demonstrated that--even in cryptocurrencies that are specifically designed to improve anonymity--it is often possible to track money as it changes hands, and in some cases to de-anonymize users entirely. With the recent proliferation of alternative cryptocurrencies, however, it becomes relevant to ask not only whether or not money can be traced as it moves within the ledger of a single cryptocurrency, but if it can in fact be traced as it moves across ledgers. This is especially pertinent given the rise in popularity of automated trading platforms such as ShapeShift, which make it effortless to carry out such cross-currency trades. In this paper, we use data scraped from ShapeShift over a thirteen-month period and the data from eight different blockchains to explore this question. Beyond developing new heuristics and creating new types of links across cryptocurrency ledgers, we also identify various patterns of cross-currency trades and of the general usage of these platforms, with the ultimate goal of understanding whether they serve a criminal or a profit-driven agenda.
In the traditional educational understanding, individuals follow the path of getting graduate or post-graduate education if they wish, after continuing their education from kindergarten to high school. Today, by getting out of this stereotype, every literate person can choose different learning environments. Now, learning any subject is up to the tip of the fingers of an individual without depending on a school building with four walls or on certain time frame. In this study, it is aimed to verify digital certificates given to the participants at the Turkish stage of the International Informatics and Computational Thinking event by using Ethereum Block Chain based smart contract. The tasks in the event were transmitted to the students in Turkey via using exam module of the Moodle Learning Management System. For this study, first a smart contract was developed in which the certificate information could be stored on the Ethereum blockchain and could be check for control purposes if necessary. Then the certificate module developed by the researcher in 2014 which uses block structure in the Moodle Learning Management System was updated and then provided to work in accordance with the smart contract in the Ethereum blockchain.
Marc Jourdan, Sébastien Blandin, Laura Wynter, Pralhad Deshpande
Bitcoin has created a new exchange paradigm within which financial transactions can be trusted without an intermediary. This premise of a free decentralized transactional network however requires, in its current implementation, unrestricted access to the ledger for peer-based transaction verification. A number of studies have shown that, in this pseudonymous context, identities can be leaked based on transaction features or off-network information. In this work, we analyze the information revealed by the pattern of transactions in the neighborhood of a given entity transaction. By definition, these features which pertain to an extended network are not directly controllable by the entity, but might enable leakage of information about transacting entities. We define a number of new features relevant to entity characterization on the Bitcoin Blockchain and study their efficacy in practice. We show that even a weak attacker with shallow data mining knowledge is able to leverage these features to characterize the entity properties.
Software sustainability is a systematic challenge that impacts broad segments of software systems. Software codebases must evolve overtime to address changing contexts and adapt to the flux in middlewares and platforms. In the process, it accumulates arbitrary complexities and its maintenance becomes progressively difficult.
Current sustainability approaches focus on the symptoms and tend to be reactive in nature, and ignore the fundamental incentive structures that drive decision-making processes. Moreover, contemporary approaches are insensitive to the uniqueness of each software project context and operate on the assumption that sustainability measurements are universally applicable to the majority of software systems.
This paper introduces a fundamentally novel peer-driven approach to managing software sustainability. The methodology ensures that software teams can define their own sustainability measures that adequately address the unique context of their project and its priorities. These measures are dynamically defined by the project peers to ensure their applicability as the project context evolves. Finally, the paper introduces Susereum, a blockchain platform that materializes the methodology and establishes novel incentive structures to systematically promote software sustainability throughout the project lifecycle.
Blockchain is distributed ledger with the advantage of high security, tamper resistant and traceability. However, in the process of the growth of Blockchain, network isolation hinders the cooperative operation among different Blockchains and greatly restricts the development of Blockchain. There is an urgent need to break the barriers among Blockchains[1], thus cross-chain communication become a new trend of the Blockchain technology[2]. In this paper, we propose CVEM, a value exchange mechanism which supports different kind of tokens transfer cross-chain. First, we put the main exchange process execute off-chain and the final result on-chain. Then, we combine Revocable Sequence Maturity Contract (RSMC) with the idea of cross-token exchange of Blockchain, and use the mechanism of multi-signatures address to constrain the users' behaviors. In addition, we introduce the Simple Payment Verification Proof (SPV Proof) to verify transactions. Our work, to some degree, shortens the transaction process delay and also ensures the security and scalability of the value exchange.
Blockchain is a game changer in nowadays information technology and financial industry. Since Nakamoto invented the concept of blockchain together with its first application called “Bitcoin”, the topic of blockchain has been inundated with the booming of cryptocurrencies. People expect this novel distributed ledger technology to bring a revolution to the entire industry and thereby grab the opportunity to expand and strengthen their business. The supply chain is treated as a typical use case to adopt blockchain and relevant technologies in many previous studies. In this paper, we conduct an interdisciplinary study on business supply chain management and the latest distributed ledger technology. In accordance with our discussion and experiments, we list three major benefits that the adoption of blockchain is able to bring to contemporary supply chain management. Meanwhile, we also identify a few of challenges that the nowadays blockchain application could not effectively excel, and the potential mitigation to those challenges as well.
Law, regulation, and private standards have evolved to enhance sustainability in value chains. However, the volume of hard and soft laws has created complexity and fragmentation for consumers and firms. In addition, global value chains are increasingly disaggregated, making it difficult for consumers to enforce breaches of sustainability representations. Blockchain, as an immutable and digital record keeping system, is a tool that can deal with this growing complexity in global value chains. Documents verifying sustainability that were once in the private domain and stored in paper copy can now be made accessible in a secure and transparent blockchain platform. Despite a growing interest in the potential of blockchain to transform businesses, there are few concrete examples or scholarly literature showing how blockchain is operationalized in practice. Using a “conceptual framework analysis” approach, we develop an Evidence, Verifiability, and Enforceability (EVE) framework to illustrate how blockchain can enhance sustainability by providing information to consumers on the origin of products, assurances as to the veracity of the information, and a mechanism to enforce representations through the blockchain smart contract function. However, there need to be safeguards put in place for blockchain technology to meet its promise and we discuss some of these challenges.
Bitcoin exchanges rely heavily on traditional intrusion detection system to secure their system. However, this reliance has proven to be high risk, since Bitcoin and other blockchain-based transactions are not easily reversible. Many of the attacks have shown that the traditional intrusion detection system is not enough to safeguard against all possible attacks, and most importantly, in some cases, it takes a long time to assess the damage. In this paper, we first describe three types of intrusion models in Bitcoin exchanges and propose a detection and mitigation system using blockchain analysis for each. The proposed detection and mitigation system exploit the decentralized and public nature of Bitcoin blockchain to complement the existing traditional intrusion detection system as a fail-safe. The proposed method provides real-time intrusion detection capability that the existing work cannot provide. Although the proposed method is specifically for Bitcoin blockchain, similar ideas can be extended to other proof-of-work based blockchain cryptocurrencies.
Blockchain is steadily becoming a disruptive technology, capable of profoundly impacting a wide range of industries. Established applications such as cryptocurrency (e.g., Bitcoin, etc.) have brought blockchain into the limelight. Blockchains, as one implementation of distributed ledgers, promises the ability to maintain critical information in a trustworthy repository without any centralized management. The reliability of blockchain-enabled applications is based on the innate immutability of stored data, maintained through cryptographic means, which enables blockchains to provide transparency, efficiency, auditability, trust, and security. Technological additions such as smart contract capabilities and various consensus algorithms have allowed novel blockchain use cases in both the public sector (e.g., identity governance, regulations, healthcare, etc.) and the private sector (e.g., finance, supply chain management, etc.).
Deepfake videos are the product of artificial intelligence or machine-learning applications that merge, combine, replace and superimpose images and video clips onto a video, creating a fake video that appears authentic. The main issue with Deepfake videos is that anyone can produce explicit content without the consent of those involved. While some of these videos are humorous and benign, the majority of them are pornographic. The faces of celebrities and other well-known (and lesser-known) individuals have been superimposed on the bodies of porn stars. The existence of this technology erodes trust in video evidence and adversely affects its probative value in court. This article describes the current and future capabilities of this technology, stresses the need to plan for its treatment as evidence in court, and draws attention to its current and future impact on the authentication process of video evidence in courts. Ultimately, as the technology improves, parallel technologies will need to be developed and utilised to identify and expose fake videos.
In summary, this study has applied TAM model to examine cryptocurrency payment adoption in Taiwanese hotels, examining the factors that are more likely to affect the behavioral intent. The empirical results suggest that intent to adopt cryptocurrency payments is affected by perceived usefulness, and perceived ease of use of these payments. In turn, perceived usefulness is affected by trust towards these payments. Interestingly, perceived usefulness was not shown to be significantly affected by different types of risks associated with cryptocurrency payments, including financial risk, technological risk, and social risk. Perceived ease of use, in turn, is affected by convenience of cryptocurrency payments; and is not shown to be significantly affected by trust.
Since the inception of blockchain and Bitcoin (Nakamoto (2008)), a decentralized-distributed ledger system and its associated cryptocurrency, respectively, the world has witnessed a slew of newer adaptations and applications. Although the original distributed ledger technology (DLT) of blockchain is deemed secure and decentralized, the confirmation of transactions is inefficient by design. Recently adopted, directed acyclic graph (DAG)-based distributed ledgers validate transactions efficiently without the physically and environmentally costly building process of blocks (Lerner (2015)). However, centrally-controlled confirmation against the odds of multiple validation disqualifies the DAG as a decentralized-distributed ledger. In this regard, we introduce an innovative DLT by reconstructing a chain of antichains based on a given DAG-pool of transactions. Each antichain (box) contains distinct nodes whose approved transactions are recursively validated by subsequently augmenting nodes. The boxer node closes the box and keeps the hash of all transactions confirmed by the box-genesis node. Designation of boxers and box-geneses is conditionally randomized for decentralization. The boxes are serially concatenated with recursive confirmation (boxchain) without incurring the cost of box generation. Rewards (boxcoin) are paid to the contributing nodes of the ecosystem whose trust is built on the doubly-secure protocol of confirmation. A value-preserving medium of payment (boxdollar) is among numerous practical applications discussed herein.
Civic crowdfunding (CC) is a popular medium for raising funds for civic projects from interested agents. With Blockchains gaining traction, we can implement CC in a reliable, transparent, and secure manner with smart contracts (SCs). The fundamental challenge in CC is free-riding. PPR, the proposal by Zubrickas [23] of giving refund bonus to the contributors, in the case of the project not getting provisioned, has attractive properties. However, as observed by Chandra et al. [7], PPR faces a challenge wherein the agents defer their contribution until the deadline. We define this delaying of contributions as a race condition. To address this, their proposal, PPS, considers the temporal aspects of a contribution. However, PPS is computationally complex, expensive to implement as an SC, and it being sophisticated, it is difficult to explain to a layperson. In this work, our goal is to identify all essential properties a refund bonus scheme must satisfy in order to curb free-riding while avoiding the race condition. We prove Contribution Monotonicity and Time Monotonicity are sufficient conditions for this. We propose three elegant refund bonus schemes satisfying these two conditions leading to three novel mechanisms for CC - PPRG, PPRE, and PPRP. We show that PPRG is the most cost-effective mechanism when deployed as an SC. We show that under certain modest assumptions on valuations of the agents, in PPRG, the project is funded at equilibrium.