Building robust m-commerce payment system on offline wireless network

Mobile commerce is one of the upcoming research area with focus on mobile payment systems. Unfortunately, the current payment systems is directly dependent on fixed infrastructure of network (cellular network), which fails to facilitate optimal level of security for the payment system. The proposed system highlights a novel approach for building a secure, scalable, and flexible e-payment systems in the distributed scenario of wireless adhoc network in offline mode of communication for enhanced security on transaction and payment process. The proposed system uses Simple Public Key Infrastructure for providing the security in payment processes. The performance analysis of the proposed model shows that the system is highly robust and secure ensuring anonymity, privacy, non-repudiation offline payment system over wireless adhoc network

zkFi: Privacy-Preserving and Regulation Compliant Transactions using Zero Knowledge Proofs

We propose a middleware solution designed to facilitate seamless integration of privacy using zero-knowledge proofs within various multi-chain protocols, encompassing domains such as DeFi, gaming, social networks, DAOs, e-commerce, and the metaverse. Our design achieves two divergent goals. zkFi aims to preserve consumer privacy while achieving regulation compliance through zero-knowledge proofs. These ends are simultaneously achievable. zkFi protocol is designed to function as a plug-and-play solution, offering developers the flexibility to handle transactional assets while abstracting away the complexities associated with zero-knowledge proofs. Notably, specific expertise in zero-knowledge proofs (ZKP) is optional, attributed to zkFi's modular approach and software development kit (SDK) availability

ORide: A Privacy-Preserving yet Accountable Ride-Hailing Service

In recent years, ride-hailing services (RHSs) have be- come increasingly popular, serving millions of users per day. Such systems, however, raise significant privacy concerns, because service providers are able to track the precise mobility patterns of all riders and drivers. In this paper, we propose ORide (Oblivious Ride), a privacy- preserving RHS based on somewhat-homomorphic en- cryption with optimizations such as ciphertext packing and transformed processing. With ORide, a service provider can match riders and drivers without learning their identities or location information. ORide offers rid- ers with fairly large anonymity sets (e.g., several thou- sands), even in sparsely populated areas. In addition, ORide supports key RHS features such as easy payment, reputation scores, accountability, and retrieval of lost items. Using real data-sets that consist of millions of rides, we show that the computational and network over- head introduced by ORide is acceptable. For example, ORide adds only several milliseconds to ride-hailing op- erations, and the extra driving distance for a driver is less than 0.5 km in more than 75% of the cases evaluated. In short, we show that a RHS can offer strong privacy guar- antees to both riders and drivers while maintaining the convenience of its services

A Novel ID-based Electronic Cash System from Pairings

Recently, Chen et al. and Juang et al. each proposed one and two e-cash payment systems respectively. They claimed that their schemes are secure. However, in this paper, we will present the shortcomings of their schemes and then propose a novel one from pairings. After security analysis and comparison, we conclude that our scheme not only is more secure but also possesses more functions that a secure electronic cash system should encompass than all of the proposed protocols

The Historical Context of Stock Settlement and Blockchain

n 1968, the U.S. stock market collapsed. 1 It did not flatline, of course, but major markets closed every Wednesday in an event now known as the \u27Wall Street Paperwork Crisis.\u27 2 This seizure was not caused by problems at the front end of a trade; brokers and dealers could easily keep up with the various client orders to buy or sell stock. Rather, the difficulties arose from back-end bottlenecks that occurred during the clearing and settlement process—the method by which a share of stock is transferred from seller to buyer. 3 This two-step process is necessary because the initial moment of contracting—the trade—is not executed on an instantaneous basis. The shares are exchanged later, thereby fulfilling the contractual commitment, via a settlement and clearing process that is often described as the \u27back-office plumbing\u27 of securities markets.

Cryptography for Bitcoin and friends

Numerous cryptographic extensions to Bitcoin have been proposed since Satoshi Nakamoto introduced the revolutionary design in 2008. However, only few proposals have been adopted in Bitcoin and other prevalent cryptocurrencies, whose resistance to fundamental changes has proven to grow with their success. In this dissertation, we introduce four cryptographic techniques that advance the functionality and privacy provided by Bitcoin and similar cryptocurrencies without requiring fundamental changes in their design: First, we realize smart contracts that disincentivize parties in distributed systems from making contradicting statements by penalizing such behavior by the loss of funds in a cryptocurrency. Second, we propose CoinShuffle++, a coin mixing protocol which improves the anonymity of cryptocurrency users by combining their transactions and thereby making it harder for observers to trace those transactions. The core of CoinShuffle++ is DiceMix, a novel and efficient protocol for broadcasting messages anonymously without the help of any trusted third-party anonymity proxies and in the presence of malicious participants. Third, we combine coin mixing with the existing idea to hide payment values in homomorphic commitments to obtain the ValueShuffle protocol, which enables us to overcome major obstacles to the practical deployment of coin mixing protocols. Fourth, we show how to prepare the aforementioned homomorphic commitments for a safe transition to post-quantum cryptography.Seit seiner revolutionären Erfindung durch Satoshi Nakamoto im Jahr 2008 wurden zahlreiche kryptographische Erweiterungen für Bitcoin vorgeschlagen. Gleichwohl wurden nur wenige Vorschläge in Bitcoin und andere weit verbreitete Kryptowährungen integriert, deren Resistenz gegen tiefgreifende Veränderungen augenscheinlich mit ihrer Verbreitung wächst. In dieser Dissertation schlagen wir vier kryptographische Verfahren vor, die die Funktionalität und die Datenschutzeigenschaften von Bitcoin und ähnlichen Kryptowährungen verbessern ohne deren Funktionsweise tiefgreifend verändern zu müssen. Erstens realisieren wir Smart Contracts, die es erlauben widersprüchliche Aussagen einer Vertragspartei mit dem Verlust von Kryptogeld zu bestrafen. Zweitens schlagen wir CoinShuffle++ vor, ein Mix-Protokoll, das die Anonymität von Benutzern verbessert, indem es ihre Transaktionen kombiniert und so deren Rückverfolgung erschwert. Sein Herzstück ist DiceMix, ein neues und effizientes Protokoll zur anonymen Veröffentlichung von Nachrichten ohne vertrauenswürdige Dritte und in der Präsenz von bösartigen Teilnehmern. Drittens kombinieren wir dieses Protokoll mit der existierenden Idee, Geldbeträge in Commitments zu verbergen, und erhalten so das ValueShuffle-Protokoll, das uns ermöglicht, große Hindernisse für den praktischen Einsatz von Mix-Protokollen zu überwinden. Viertens zeigen wir, wie die dabei benutzten Commitments für einen sicheren Übergang zu Post-Quanten-Kryptographie vorbereitet werden können