PDFS: Practical Data Feed Service for Smart Contracts

Smart contracts are a new paradigm that emerged with the rise of the blockchain technology. They allow untrusting parties to arrange agreements. These agreements are encoded as a programming language code and deployed on a blockchain platform, where all participants execute them and maintain their state. Smart contracts are promising since they are automated and decentralized, thus limiting the involvement of third trusted parties, and can contain monetary transfers. Due to these features, many people believe that smart contracts will revolutionize the way we think of distributed applications, information sharing, financial services, and infrastructures. To release the potential of smart contracts, it is necessary to connect the contracts with the outside world, such that they can understand and use information from other infrastructures. For instance, smart contracts would greatly benefit when they have access to web content. However, there are many challenges associated with realizing such a system, and despite the existence of many proposals, no solution is secure, provides easily-parsable data, introduces small overheads, and is easy to deploy. In this paper we propose PDFS, a practical system for data feeds that combines the advantages of the previous schemes and introduces new functionalities. PDFS extends content providers by including new features for data transparency and consistency validations. This combination provides multiple benefits like content which is easy to parse and efficient authenticity verification without breaking natural trust chains. PDFS keeps content providers auditable, mitigates their malicious activities (like data modification or censorship), and allows them to create a new business model. We show how PDFS is integrated with existing web services, report on a PDFS implementation and present results from conducted case studies and experiments.Comment: Blockchain; Smart Contracts; Data Authentication; Ethereu

Cloud-Based Secure Logger for Medical Devices

A logger in the cloud capable of keeping a secure, time-synchronized and tamper-evident log of medical device and patient information allows efficient forensic analysis in cases of adverse events or attacks on interoperable medical devices. A secure logger as such must meet requirements of confidentiality and integrity of message logs and provide tamper-detection and tamper-evidence. In this paper, we propose a design for such a cloud-based secure logger using the Intel Software Guard Extensions (SGX) and the Trusted Platform Module (TPM). The proposed logger receives medical device information from a dongle attached to a medical device. The logger relies on SGX, TPM and standard encryption to maintain a secure communication channel even on an untrusted network and operating system. We also show that the logger is resilient against different kinds of attacks such as Replay attacks, Injection attacks and Eavesdropping attacks

This time is different : Facebook’s Libra can improve both financial inclusion and global financial stability as a viable alternative currency to the U.S. Dollar

Purpose: The aim of this study is to determine the relationship between the propagation of high-magnitude crises since the late 1990s and emergence of cryptocurrencies in the aftermath of the global financial crisis of 2008. Design and Methodology: The study was based on a literature review of the interaction between financial crises and evolution of money in the digital age. A high-level technical overview of Libra and blockchain is provided. The broad analysis of Libra coin looks at various models and categories of implementation approaches. The study discusses the components of blockchain technology and provides illustrative visuals when possible. We also compare consensus models used in the Libra and Bitcoin blockchain networks. The analysis also touches on the use of blockchain technology in applications such as smart contracts. Findings: The study shows that cryptocurrencies are not only a natural but an inevitable transformation in the evolution of money. As with any new technology, Facebook’s Libra is going to cause a great deal of disruption in the existing ecosystem of cryptocurrencies that has taken a decade to form. On the other hand, Libra’s financial inclusion and global stability as a public good promises to revolutionize the cryptocurrency world. Practical Implications: If Facebook’s Libra doesn’t sputter out, it will spur central banks to introduce their own cryptocurrency projects. Libra’s vast scale will make access to intermediation by banks easier, faster, and cheaper. Unlike Bitcoin, Libra will be backed by a basket of stable currencies as well as low-risk government bonds and central bank reserve assets. Originality/Value: This study presents a clear picture of both advantages and potential risks of Libra which is considered to be a new invention eventhough Bitcoin has been around more than a decade. The study warns regulators and law makers along with central banks who are running headlong into backlash to Libra can harm consumers more than protect them. Punishing Facebook with a troubled past for violation of privacy and exploitation of users’ data could adversely affect innovation and discourage developments of cryptocurrencies.peer-reviewe