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Bitcoin is a decentralized payment system that relies on Proof-of-Work (PoW) to verify payments. Nowadays, Bitcoin is increasingly used in a number of fast payment scenarios, where the time between the exchange of currency and goods is short (in the order of few seconds). While the Bitcoin payment verification scheme is designed to prevent double-spending, our results show that the system requires tens of minutes to verify a transaction and is therefore inappropriate for fast payments. An example of this use of Bitcoin was recently reported in the media: Bitcoins were used as a form of \emph{fast} payment in a local fast-food restaurant. Until now, the security of fast Bitcoin payments has not been studied. In this paper, we analyze the security of using Bitcoin for fast payments. We show that, unless appropriate detection techniques are integrated in the current Bitcoin implementation, double-spending attacks on fast payments succeed with overwhelming probability and can be mounted at low cost. We further show that the measures recommended by Bitcoin developers for the use of Bitcoin in fast payments are not always effective in detecting double-spending; we show that if those recommendations are integrated in future Bitcoin implementations, double-spending attacks on Bitcoin will still be possible. Finally, we propose and implement a modification to the existing Bitcoin implementation that ensures the detection of double-spending attacks against fast payments.

In today's digital age, FinTech’s have become universal, transforming the way individuals conduct financial transactions. However, with the convenience of Fintech also come challenges that users encounter. This book chapter investigates into the changing landscape of Fintech challenges, drawing insights from a comprehensive survey conducted among various respondents The survey finds three primary obstacles faced by users during Fintech: network issues, time consumption, and privacy concerns. Notably, a significant proportion of respondents reported encountering network-related problems, highlighting the critical role of stable connectivity in facilitating seamless transactions. Moreover, the chapter explores into the foiling experienced by users due to the time-and privacy nature of the payment process, shedding light on the need for streamlined and efficient payment mechanisms. Building upon the survey findings, the chapter offers valuable insights into potential strategies and solutions to address these challenges. By elucidating practical approaches and technological innovations aimed at enhancing Fintech systems' efficiency and security, the chapter equips readers with actionable knowledge to navigate the digital payment landscape effectively. This study's findings add to academic discussion and have practical implications for policymakers, industry practitioners, and educators.

One promising area of mobile commerce (m-commerce) that is receiving growing attention globally is mobile payment (m-payment). m-payment refers to making payments using mobile devices. Understanding the determinants of consumer acceptance of m-payment will provide important theoretical contributions to the field and lead to the development of more effective m-payment devices and systems. By expanding the Technology Acceptance Model (TAM) and the Innovation Diffusion Theory (IDT), this study proposes a research model that examines the factors which determine consumer acceptance of m-payment. Significant support for the model was found in the data collected from a survey of 299 potential m-payment users. Implications for practice and suggestions for future research are provided.

Out-of-pocket (OOP) payments are the principal means of financing health care throughout much of Asia. We estimate the magnitude and distribution of OOP payments for health care in fourteen countries and territories accounting for 81% of the Asian population. We focus on payments that are catastrophic, in the sense of severely disrupting household living standards, and approximate such payments by those absorbing a large fraction of household resources. Bangladesh, China, India, Nepal and Vietnam rely most heavily on OOP financing and have the highest incidence of catastrophic payments. Sri Lanka, Thailand and Malaysia stand out as low to middle income countries that have constrained both the OOP share of health financing and the catastrophic impact of direct payments. In most low/middle-income countries, the better-off are more likely to spend a large fraction of total household resources on health care. This may reflect the inability of the poorest of the poor to divert resources from other basic needs and possibly the protection of the poor from user charges offered in some countries. But in China, Kyrgyz and Vietnam, where there are no exemptions of the poor from charges, they are as, or even more, likely to incur catastrophic payments.

Bit coin is the first digital currency to see widespread adoption. While payments are conducted between pseudonyms, Bit coin cannot offer strong privacy guarantees: payment transactions are recorded in a public decentralized ledger, from which much information can be deduced. Zero coin (Miers et al., IEEE S&P 2013) tackles some of these privacy issues by unlinking transactions from the payment's origin. Yet, it still reveals payments' destinations and amounts, and is limited in functionality. In this paper, we construct a full-fledged ledger-based digital currency with strong privacy guarantees. Our results leverage recent advances in zero-knowledge Succinct Non-interactive Arguments of Knowledge (zk-SNARKs). First, we formulate and construct decentralized anonymous payment schemes (DAP schemes). A DAP scheme enables users to directly pay each other privately: the corresponding transaction hides the payment's origin, destination, and transferred amount. We provide formal definitions and proofs of the construction's security. Second, we build Zero cash, a practical instantiation of our DAP scheme construction. In Zero cash, transactions are less than 1 kB and take under 6 ms to verify - orders of magnitude more efficient than the less-anonymous Zero coin and competitive with plain Bit coin.

BACKGROUND: In the current debate over tort reform, critics of the medical malpractice system charge that frivolous litigation--claims that lack evidence of injury, substandard care, or both--is common and costly. METHODS: Trained physicians reviewed a random sample of 1452 closed malpractice claims from five liability insurers to determine whether a medical injury had occurred and, if so, whether it was due to medical error. We analyzed the prevalence, characteristics, litigation outcomes, and costs of claims that lacked evidence of error. RESULTS: For 3 percent of the claims, there were no verifiable medical injuries, and 37 percent did not involve errors. Most of the claims that were not associated with errors (370 of 515 [72 percent]) or injuries (31 of 37 [84 percent]) did not result in compensation; most that involved injuries due to error did (653 of 889 [73 percent]). Payment of claims not involving errors occurred less frequently than did the converse form of inaccuracy--nonpayment of claims associated with errors. When claims not involving errors were compensated, payments were significantly lower on average than were payments for claims involving errors (313,205 dollars vs. 521,560 dollars, P=0.004). Overall, claims not involving errors accounted for 13 to 16 percent of the system's total monetary costs. For every dollar spent on compensation, 54 cents went to administrative expenses (including those involving lawyers, experts, and courts). Claims involving errors accounted for 78 percent of total administrative costs. CONCLUSIONS: Claims that lack evidence of error are not uncommon, but most are denied compensation. The vast majority of expenditures go toward litigation over errors and payment of them. The overhead costs of malpractice litigation are exorbitant.

BACKGROUND: Increased attention is being paid to the amount and types of medical services rendered in the period before death. There is a popular impression that a greater share of resources is being devoted to dying patients than in the past. We examined trends in the proportion of Medicare expenditures for persons 65 years old or older in their last year of life to determine whether there were any changes from 1976 to 1988. METHODS: Using Medicare program data for 1976, 1980, 1985, and 1988, we classified Medicare payments according to whether they were made for people in their last year of life (decedents) or for survivors. We also assigned expenses for care in the last year of life according to intervals of 30 days before the person's death and examined trends according to age. RESULTS: Reflecting the large overall increase in Medicare spending, Medicare costs for decedents rose from $3,488 per person-year in 1976 to $13,316 in 1988. However, Medicare payments for decedents as a percentage of the total Medicare budget changed little, fluctuating between 27.2 and 30.6 percent during the study period. Payments for care during the last 60 days of life expressed as a percentage of payments for the last year also held steady at about 52 percent. Furthermore, the pattern of lower payments for older as compared with younger decedents also prevailed throughout the study period. CONCLUSIONS: The same forces that have acted to increase overall Medicare expenditures have affected care for both decedents and survivors. There is no evidence that persons in the last year of life account for a larger share of Medicare expenditures than in earlier years.

Past expenses have been shown to influence future spending behavior by depleting available budgets. However, a prerequisite for this relationship is the accurate recall of past payments and the experiencing of the full aversive impact associated with them. This article shows that the use of different payment mechanisms influences both these factors and hence moderates the effects of past payments on future spending. Specifically, past payments strongly reduce purchase intention when the payment mechanism requires the consumer to write down the amount paid (rehearsal) and when the consumer's wealth is depleted immediately rather than with a delay (immediacy). Two experiments show support for the proposed theoretical framework. Copyright 2001 by the University of Chicago.

Offering payment to clinical research subjects, in an effort to enhance recruitment by providing an incentive to take part or enabling subjects to participate without financial sacrifice, is a common yet uneven and contentious practice in the US. Concern exists regarding the potential for payment to unduly influence participation and thus obscure risks, impair judgment, or encourage misrepresentation. Heightening these concerns is the participation not only of adults but also of children in pediatric research trials. Thorough assessment of risks, careful eligibility screening, and attention to a participant's freedom to refuse all serve to reduce the possibility of compensation adversely affecting the individual and/or the study. Institutional review boards currently evaluate payment proposals with minimal guidance from federal regulations. Here, reasons for providing payment, payment models, ethical concerns, and areas for further research are examined.

New targets have been set for value-based payment: 85% of Medicare fee-for-service payments should be tied to quality or value by 2016, and 30% of Medicare payments should be tied to quality or value through alternative payment models by 2016 (50% by 2018).

We measure the change in household spending caused by receipt of the economic stimulus payments of 2008, using questions added to the Consumer Expenditure Survey and variation from the randomized timing of disbursement. Households spent 12–30 percent (depending on specification) of their payments on nondurable goods during the three-month period of payment receipt, and a significant amount more on durable goods, primarily vehicles, bringing the total response to 50–90 percent of the payments. The responses are substantial and significant for older, lower-income, and home-owning households. Spending does not vary significantly with the method of disbursement (check versus electronic transfer). (JEL D12, D14, E21, E62)

ABSTRACT We study merger and acquisition (M&A) payment choices of European bidders for publicly and privately held targets in the 1997–2000 period. Europe is an ideal venue for studying the importance of corporate governance in making M&A payment choices, given the large number of closely held firms and the wide range of capital markets, institutional settings, laws, and regulations. The tradeoff between corporate governance concerns and debt financing constraints is found to have a large bearing on the bidder's payment choice. Consistent with earlier evidence, we find that several deal and target characteristics significantly affect the method of payment choice.

Preface - Acknowledgements - Alternative Theories of Growth Performance:I The Supply Orientated and Neoclassical Approaches - Alternative Theories of Growth Performance:II The Demand Orientated Approach - The Balance of Payments Constraint as an Explanation of International Growth Rate Differences - Non-Price Competition, Trade and the Balance of Payments - Critiques and Defences of the Balance of Payments Constrained Growth Model - Economic Growth, the Harrod Foreign Trade Multiplier and the Hicks Super-Multiplier - Export-Led Growth and the Balance of Payments Constraint - Export-Led Growth, Regional Problems and Cumulative Causation

Purpose – The purpose of this paper is to uncover the effects of perceived transaction convenience (PTC) and perceived transaction speed (PTS) on unified theory of acceptance and use of technology (UTAUT) in the context of m-payment. Design/methodology/approach – A predictive analysis approach was used to examine the PTC and PTS using a two-stage partial least square (PLS) and neural network (NN) analyses. Findings – The findings reveal that only effort expectancy (EE) and facilitating conditions (FC) were discovered to significantly influence BI. More importantly, PTC was found to have positive significant relationship with EE and performance expectancy (PE). Moreover, PTS also supported the positive relationship with BI and EE. Practical implications – The findings of the study provided further insights to mobile payment service providers, online banking industry players, and all decision makers and stakeholders involved. Originality/value – Despite of many attempts devoted to understand m-payment adoption, the effects of PTC and PTS on m-payment are not well understood.

The standard model of labor is one in which individuals trade their time and energy in return for monetary rewards. Building on Fiske's relational theory (1992), we propose that there are two types of markets that determine relationships between effort and payment: monetary and social. We hypothesize that monetary markets are highly sensitive to the magnitude of compensation, whereas social markets are not. This perspective can shed light on the well-established observation that people sometimes expend more effort in exchange for no payment (a social market) than they expend when they receive low payment (a monetary market). Three experiments support these ideas. The experimental evidence also demonstrates that mixed markets (markets that include aspects of both social and monetary markets) more closely resemble monetary than social markets.

Many of the services supplied by nature are externalities. Economic theory suggests that some form of subsidy or contracting between the beneficiaries and the providers could result in an optimal supply of environmental services. Moreover, if the poor own resources that give them a comparative advantage in the supply of environmental services, then payments for environmental services (PES) can improve environmental and poverty outcomes. While the theory is relatively straightforward, the practice is not, particularly in developing countries where institutions are weak. This article reviews the empirical literature on PES additionality by asking, “Do payments deliver environmental services, everything else being equal, or, at least, the land-use changes believed to generate environmental services?” We examine both qualitative case studies and rigorous econometric quasi-experimental analyses. We find that government-coordinated PES have caused modest or no reversal of deforestation. Case studies of smaller-scale, user-financed PES schemes claim more substantial impacts, but few of these studies eliminate rival explanations for the positive effects. We conclude by discussing how the dearth of evidence about PES impacts, and unanswered questions about institutional preconditions and motivational “crowding out,” limit the prospects for using international carbon payments to reduce emissions from deforestation and degradation.

<i>International donors invest billions of dollars to conserve ecosystems in low-income nations. The most common investments aim to encourage commercial activities, such as ecotourism, that indirectly generate ecosystem protection as a joint product. We demonstrate that paying for ecosystem protection directly can be far more cost-effective. Although direct-payment initiatives have imposing institutional requirements, we argue that all conservation initiatives face similar challenges. Thus conservation practitioners would be well advised to implement the first-best direct-payment approach, rather than a second-best policy option. An empirical example illustrates the spectacular cost savings that can be realized by direct-payment initiatives.</i> (JEL H21, Q28)

Payments for environmental services (PES) are part of a new and more direct conservation paradigm, explicitly recognizing the need to bridge the interests of landowners and outsiders. Eloquent theoretical assessments have praised the absolute advantages of PES over traditional conservation approaches. Some pilot PES exist in the tropics, but many field practitioners and prospective service buyers and sellers remain skeptical about the concept. This paper aims to help demystify PES for non-economists, starting with a simple and coherent definition of the term. It then provides practical ‘how-to' hints for PES design. It considers the likely niche for PES in the portfolio of conservation approaches. This assessment is based on a literature review, combined with field observations from research in Latin America and Asia. It concludes that service users will continue to drive PES, but their willingness to pay will only rise if schemes can demonstrate clear additionality vis-à-vis carefully established baselines, if trust-building processes with service providers are sustained, and PES recipients' livelihood dynamics is better understood. PES best suits intermediate and/or projected threat scenarios, often in marginal lands with moderate conservation opportunity costs. People facing credible but medium-sized environmental degradation are more likely to become PES recipients than those living in relative harmony with Nature. The choice between PES cash and in-kind payments is highly context-dependent. Poor PES recipients are likely to gain from participation, though their access might be constrained and non-participating landless poor could lose out. PES is a highly promising conservation approach that can benefit buyers, sellers and improve the resource base, but it is unlikely to completely outstrip other conservation instruments.