16,028 research outputs found

    An Anonymous Credit Card System

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    Credit cards have many important benefits; however, these same benefits often carry with them many privacy concerns. In particular, the need for users to be able to monitor their own transactions, as well as bank's need to justify its payment requests from cardholders, entitle the latter to maintain a detailed log of all transactions its credit card customers were involved in. A bank can thus build a profile of each cardholder even without the latter's consent. In this paper, we present a practical and accountable anonymous credit system based on ecash, with a privacy preserving mechanism for error correction and expense-reporting

    The economics of payment finality

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    Payment finality is critical to decentralized exchange. By specifying how the transfer of one type of claim extinguishes another, the rules governing finality minimize opportunities for default along credit chains and allocate other risks. ; The authors provide a basic analysis of finality and its role in facilitating exchange. They first present a simple, historically based model of transferable debt and finality. The discussion demonstrates the desirability of transferable debt and why rules governing payment finality are needed to sort out who will bear the losses in the event of default. Over time, the introduction of such rules helped establish the concept of negotiability, which greatly increased the efficiency of trade. ; A second model shows how a more modern payment system works. The large volume and scope of payments in modern systems have resulted in disparate sets of finality rules. For example, the finality of check payments is generally tentative, and the risks are often concentrated on a single party. Credit and debit card payments are generally more final, and the liability for potential losses tends to be shared among participants. Choosing the degree of finality for a given situation involves a trade-off between the benefits of finality and the costs of an erroneous or fraudulent transfer. The introduction of new technologies for payments may improve these trade-offs, but finality will remain the essential service provided.Payment systems ; Credit cards ; Checks

    Fraud detections for online businesses: a perspective from blockchain technology

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    Background: The reputation system has been designed as an effective mechanism to reduce risks associated with online shopping for customers. However, it is vulnerable to rating fraud. Some raters may inject unfairly high or low ratings to the system so as to promote their own products or demote their competitors. Method: This study explores the rating fraud by differentiating the subjective fraud from objective fraud. Then it discusses the effectiveness of blockchain technology in objective fraud and its limitation in subjective fraud, especially the rating fraud. Lastly, it systematically analyzes the robustness of blockchain-based reputation systems in each type of rating fraud. Results: The detection of fraudulent raters is not easy since they can behave strategically to camouflage themselves. We explore the potential strengths and limitations of blockchain-based reputation systems under two attack goals: ballot-stuffing and bad-mouthing, and various attack models including constant attack, camouflage attack, whitewashing attack and sybil attack. Blockchain-based reputation systems are more robust against bad-mouthing than ballot-stuffing fraud. Conclusions: Blockchain technology provides new opportunities for redesigning the reputation system. Blockchain systems are very effective in preventing objective information fraud, such as loan application fraud, where fraudulent information is fact-based. However, their effectiveness is limited in subjective information fraud, such as rating fraud, where the ground-truth is not easily validated. Blockchain systems are effective in preventing bad mouthing and whitewashing attack, but they are limited in detecting ballot-stuffing under sybil attack, constant attacks and camouflage attack
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