An Empirical Study of Namecoin and Lessons for Decentralized Namespace Design
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Linking Wallets and Deanonymizing Transactions in the Ripple Network
Proceedings on Privacy Enhancing Technologies ; 2016 (4):436–453 Pedro Moreno-Sanchez*, Muhammad Bilal Zafar, and Aniket Kate* Listening to Whispers of Ripple: Linking Wallets and Deanonymizing Transactions in the Ripple Network Abstract: The decentralized I owe you (IOU) transac- 1 Introduction tion network Ripple is gaining prominence as a fast, low- cost and efficient method for performing same and cross- In recent years, we have observed a rather unexpected currency payments. Ripple keeps track of IOU credit its growth of IOU transaction networks such as Ripple [36, users have granted to their business partners or friends, 40]. Its pseudonymous nature, ability to perform multi- and settles transactions between two connected Ripple currency transactions across the globe in a matter of wallets by appropriately changing credit values on the seconds, and potential to monetize everything [15] re- connecting paths. Similar to cryptocurrencies such as gardless of jurisdiction have been pivotal to their suc- Bitcoin, while the ownership of the wallets is implicitly cess so far. In a transaction network [54, 55, 59] such as pseudonymous in Ripple, IOU credit links and transac- Ripple [10], users express trust in each other in terms tion flows between wallets are publicly available in an on- of I Owe You (IOU) credit they are willing to extend line ledger. In this paper, we present the first thorough each other. This online approach allows transactions in study that analyzes this globally visible log and charac- fiat money, cryptocurrencies (e.g., bitcoin1) and user- terizes the privacy issues with the current Ripple net- defined currencies, and improves on some of the cur- work. -
Ethereum Based Domain Name System Using Smart Contracts
ETHEREUM BASED DOMAIN NAME SYSTEM USING SMART CONTRACTS (BC-DNS) A Project Presented to the faculty of the Department of Computer Science California State University, Sacramento Submitted in partial satisfaction of the requirements for the degree of MASTER OF SCIENCE in Computer Science by Rodney Pinto SPRING 2019 © 2019 Rodney Pinto ALL RIGHTS RESERVED ii ETHEREUM BASED DOMAIN NAME SYSTEM USING SMART CONTRACTS (BC-DNS) A Project by Rodney Pinto Approved by: __________________________________, Committee Chair Dr. Jun Dai. __________________________________, Second Reader Dr. Xuyu Wang. ____________________________ Date iii Student: Rodney Pinto I certify that this student has met the requirements for format contained in the university format manual, and that this project is suitable for shelving in the library and credit is to be awarded for the project. __________________________, Graduate Coordinator ____________________ Dr. Jinsong Ouyang, Ph.D. Date Department of Computer Science iv Abstract of ETHEREUM BASED DOMAIN NAME SYSTEM USING SMART CONTRACTS (BC-DNS) by Rodney Pinto One of the most critical resources that ensure the current working of the internet is the domain name system (DNS). It is a decentralized, hierarchical naming system that is responsible for translating the human-readable domain name to its associated IP address. The use of DNS thus eliminates the need for humans to remember the IP address of all their favorite websites (such as 172.217.6.68 an IPV4 address for google.com). Despite its widespread use, DNS is vulnerable to various security issues. This project focuses on replicating the basic functionality of the existing DNS on the blockchain and deploying it on a peer to peer network making it completely decentralized and, in the process, make it a bit more secure and reliable by addressing few of the security vulnerabilities of the existing system. -
Blocksci: Design and Applications of a Blockchain Analysis Platform
BlockSci: Design and applications of a blockchain analysis platform Harry Kalodner Steven Goldfeder Alishah Chator [email protected] [email protected] [email protected] Princeton University Princeton University Johns Hopkins University Malte Möser Arvind Narayanan [email protected] [email protected] Princeton University Princeton University ABSTRACT to partition eectively. In fact, we conjecture that the use of a tra- Analysis of blockchain data is useful for both scientic research ditional, distributed transactional database for blockchain analysis and commercial applications. We present BlockSci, an open-source has innite COST [5], in the sense that no level of parallelism can software platform for blockchain analysis. BlockSci is versatile in outperform an optimized single-threaded implementation. its support for dierent blockchains and analysis tasks. It incorpo- BlockSci comes with batteries included. First, it is not limited rates an in-memory, analytical (rather than transactional) database, to Bitcoin: a parsing step converts a variety of blockchains into making it several hundred times faster than existing tools. We a common, compact format. Currently supported blockchains in- describe BlockSci’s design and present four analyses that illustrate clude Bitcoin, Litecoin, Namecoin, and Zcash (Section 2.1). Smart its capabilities. contract platforms such as Ethereum are outside our scope. Second, This is a working paper that accompanies the rst public release BlockSci includes a library of useful analytic and visualization tools, of BlockSci, available at github.com/citp/BlockSci. We seek input such as identifying special transactions (e.g., CoinJoin) and linking from the community to further develop the software and explore addresses to each other based on well-known heuristics (Section other potential applications. -
Merged Mining: Curse Or Cure?
Merged Mining: Curse or Cure? Aljosha Judmayer, Alexei Zamyatin, Nicholas Stifter, Artemios Voyiatzis, Edgar Weippl SBA Research, Vienna, Austria (firstletterfirstname)(lastname)@sba-research.org Abstract: Merged mining refers to the concept of mining more than one cryp- tocurrency without necessitating additional proof-of-work effort. Although merged mining has been adopted by a number of cryptocurrencies already, to this date lit- tle is known about the effects and implications. We shed light on this topic area by performing a comprehensive analysis of merged mining in practice. As part of this analysis, we present a block attribution scheme for mining pools to assist in the evaluation of mining centralization. Our findings disclose that mining pools in merge-mined cryptocurrencies have operated at the edge of, and even beyond, the security guarantees offered by the underlying Nakamoto consensus for ex- tended periods. We discuss the implications and security considerations for these cryptocurrencies and the mining ecosystem as a whole, and link our findings to the intended effects of merged mining. 1 Introduction The topic of merged mining has received little attention from the scientific community, despite having been actively employed by a number of cryptocurrencies for several years. New and emerging cryptocurrencies such as Rootstock continue to consider and expand on the concept of merged mining in their designs to this day [19]. Merged min- ing refers to the process of searching for proof-of-work (PoW) solutions for multiple cryptocurrencies concurrently without requiring additional computational resources. The rationale behind merged mining lies in leveraging on the computational power of different cryptocurrencies by bundling their resources instead of having them stand in direct competition, and also to serve as a bootstrapping mechanism for small and fledgling networks [27, 33]. -
Decentralized Reputation Model and Trust Framework Blockchain and Smart Contracts
IT 18 062 Examensarbete 30 hp December 2018 Decentralized Reputation Model and Trust Framework Blockchain and Smart contracts Sujata Tamang Institutionen för informationsteknologi Department of Information Technology Abstract Decentralized Reputation Model and Trust Framework: Blockchain and Smart contracts Sujata Tamang Teknisk- naturvetenskaplig fakultet UTH-enheten Blockchain technology is being researched in diverse domains for its ability to provide distributed, decentralized and time-stamped Besöksadress: transactions. It is attributed to by its fault-tolerant and zero- Ångströmlaboratoriet Lägerhyddsvägen 1 downtime characteristics with methods to ensure records of immutable Hus 4, Plan 0 data such that its modification is computationally infeasible. Trust frameworks and reputation models of an online interaction system are Postadress: responsible for providing enough information (e.g., in the form of Box 536 751 21 Uppsala trust score) to infer the trustworthiness of interacting entities. The risk of failure or probability of success when interacting with an Telefon: entity relies on the information provided by the reputation system. 018 – 471 30 03 Thus, it is crucial to have an accurate, reliable and immutable trust Telefax: score assigned by the reputation system. The centralized nature of 018 – 471 30 00 current trust systems, however, leaves the valuable information as such prone to both external and internal attacks. This master's thesis Hemsida: project, therefore, studies the use of blockchain technology as an http://www.teknat.uu.se/student infrastructure for an online interaction system that can guarantee a reliable and immutable trust score. It proposes a system of smart contracts that specify the logic for interactions and models trust among pseudonymous identities of the system. -
Impossibility of Full Decentralization in Permissionless Blockchains
Impossibility of Full Decentralization in Permissionless Blockchains Yujin Kwon*, Jian Liuy, Minjeong Kim*, Dawn Songy, Yongdae Kim* *KAIST {dbwls8724,mjkim9394,yongdaek}@kaist.ac.kr yUC Berkeley [email protected],[email protected] ABSTRACT between achieving good decentralization in the consensus protocol Bitcoin uses the proof-of-work (PoW) mechanism where nodes earn and not relying on a TTP exists. rewards in return for the use of their computing resources. Although this incentive system has attracted many participants, power has, CCS CONCEPTS at the same time, been significantly biased towards a few nodes, • Security and privacy → Economics of security and privacy; called mining pools. In addition, poor decentralization appears not Distributed systems security; only in PoW-based coins but also in coins that adopt proof-of-stake (PoS) and delegated proof-of-stake (DPoS) mechanisms. KEYWORDS In this paper, we address the issue of centralization in the consen- Blockchain; Consensus Protocol; Decentralization sus protocol. To this end, we first define ¹m; ε; δº-decentralization as a state satisfying that 1) there are at least m participants running 1 INTRODUCTION a node, and 2) the ratio between the total resource power of nodes Traditional currencies have a centralized structure, and thus there run by the richest and the δ-th percentile participants is less than exist several problems such as a single point of failure and corrup- or equal to 1 + ε. Therefore, when m is sufficiently large, and ε and tion. For example, the global financial crisis in 2008 was aggravated δ are 0, ¹m; ε; δº-decentralization represents full decentralization, by the flawed policies of banks that eventually led to many bank which is an ideal state. -
TITLE PAGE Bitcoin and Stock Markets. Are They Connected? Evidence from Asean Emerging Economies Abdollah Ah Mand*1, Hassanudin
Bitcoin and Stock Markets: Are They Connected? Evidence from Asean Emerging Economies Abdollah Ah Mand ( [email protected] ) Sunway University Hassanudin Mohd Thas Thaker Sunway University Research Keywords: Cryptocurrencies, bitcoin, stock market, emerging economies Posted Date: May 12th, 2020 DOI: https://doi.org/10.21203/rs.3.rs-25524/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License TITLE PAGE Bitcoin and Stock Markets. Are they Connected? Evidence from Asean Emerging Economies Abdollah Ah Mand*1, Hassanudin Mohd Thas Thaker2 Email of corresponding author: [email protected] 1,2 Sunway University, Malaysia Abstract Background: Cryptocurrencies, especially Bitcoin, has become popular for investors in recent years. The volatility of bitcoin and time horizon are the center point for investment decisions. However, attention is not often drawn to the relationship between bitcoin and equity indices. This study investigates the volatility and time frequency domain of bitcoin among five Asean countries through a rich database which covers daily data from July 2010 until April 2019. Methods: Advanced econometrics and Wavelets Cross-Coherence Spectrograms, this study investigates the existence of long run association between bitcoin and the studied market indices. M-GARCH analysis is been employed to investigate the unconditional volatility of market indices and Bitcoin. Results: The findings present the long run association with positive (Philippines) and negative (Japan, Korea, Singapore, Hong Kong) relations. Moreover, only one market (KOREA) shows a short run association with bitcoin. The M- GARCH analysis reveals, most of the selected Asean countries have a low unconditional volatility with bitcoin. -
Identifier System Attack Mitigation Methodology DATE: 13 February 2017 Identifier System Attack Mitigation Methodology
Identifier System Attack Mitigation Methodology DATE: 13 February 2017 Identifier System Attack Mitigation Methodology Introduction This document is part of ICANN’s effort to contribute to enhancing the Stability, Security, and Resiliency (SSR) of the Internet’s system of unique identifiers (“Internet Identifiers”) by working with the Community to identify and increase awareness of related attacks and to promote broader adoption of attack mitigation practices. This effort also addresses Recommendation #12 of the Security, Stability & Resiliency (SSR) Review Team (SSR-RT) by creating an Identifier System Attack Mitigation Methodology. Specifically, this document identifies and prioritizes types of attacks against the Identifier System, providing a stepping-off point for ICANN to coordinate with the Community to develop a series of short technical documents (“Tech Notes”) on actual high-impact attacks and emerging high-risk vulnerabilities. This document will be periodically updated to reflect evolution of both the Identifier System and the cybercrime landscape, supporting on-going efforts within both ICANN and the Community to mitigate attacks that pose the greatest risk to Identifier System SSR. Authors: Lisa Phifer and David Piscitello Page 1 Identifier System Attack Mitigation Methodology DATE: 13 February 2017 Attack Mitigation Methodology ICANN is proposing a new Identifier System Attack Mitigation Methodology to: • Identify, prioritize, and periodically refresh a list of top Identifier System attacks; • Develop guidance on actual high-impact attacks and emerging high-risk vulnerabilities; • Describe corresponding attack mitigation practices that are commonly considered useful; and • Encourage broader adoption of those practices via contracts, agreements, incentives, etc. This document represents the first component of this methodology. -
Blockchain-Based Address Alias System
Article Blockchain-Based Address Alias System Norbert Bodziony , Paweł Jemioło * , Krzysztof Kluza and Marek R. Ogiela AGH University of Science and Technology, Faculty of Electrical Engineering, Automatics, Computer Science and Biomedical Engineering, al. A. Mickiewicza 30, 30-059 Krakow, Poland; [email protected] (N.B.); [email protected] (K.K.); [email protected] (M.R.O.) * Correspondence: [email protected] Abstract: In recent years, blockchains systems have seen massive adoption in retail and enterprise environments. Cryptocurrencies become more widely adopted, and many online businesses have decided to add the most popular ones, like Bitcoin or Ethereum, next to Visa or Mastercard payments. Due to the decentralized nature of blockchain-based systems, there is no possible way to revert confirmed transactions. It may result in losses caused by human error or poor design of the user interface. We created a cryptocurrency wallet with a full on-chain solution for aliasing accounts and tokens to improve user experience and avoid unnecessary errors. The aliasing system consists of a number of smart contracts deployed on top of the blockchain network that give the ability to register aliases to accounts and tokens and use them instead of opaque addresses. Our solution shows how performant modern blockchains are and presents a way of building fully decentralized applications that can compete with centralized ones in terms of performance. Keywords: blockchain; cryptocurrency; wallet; aliasing system; Solana Citation: Bodziony, N.; Jemioło, P.; 1. Introduction Kluza, K.; Ogiela, M.R. Blockchain- Blockchain [1,2] space is one of the most rapidly growing ecosystems right now. -
Thesis That TW-OR Forwards All DNS Queries to a Resolver in China
The Impact of DNSSEC on the Internet Landscape Von der Fakult¨atf¨urIngenieurwissenschaften, Abteilung Informatik und Angewandte Kognitionswissenschaft der Universit¨atDuisburg-Essen zur Erlangung des akademischen Grades Doktor der Ingenieurwissenschaften genehmigte Dissertation von Matth¨ausWander aus Lubin (L¨uben) Gutachter: Prof. Dr.-Ing. Torben Weis Prof. Dr.-Ing. Felix Freiling Tag der m¨undlichen Pr¨ufung:19. Juni 2015 Abstract In this dissertation we investigate the security deficiencies of the Domain Name System (DNS) and assess the impact of the DNSSEC security extensions. DNS spoofing attacks divert an application to the wrong server, but are also used routinely for blocking access to websites. We provide evidence for systematic DNS spoofing in China and Iran with measurement-based analyses, which allow us to examine the DNS spoofing filters from van- tage points outside of the affected networks. Third-parties in other countries can be affected inadvertently by spoofing-based domain filtering, which could be averted with DNSSEC. The security goals of DNSSEC are data integrity and authenticity. A point solution called NSEC3 adds a privacy assertion to DNSSEC, which is supposed to prevent disclosure of the domain namespace as a whole. We present GPU-based attacks on the NSEC3 privacy assertion, which allow efficient recovery of the namespace contents. We demonstrate with active measurements that DNSSEC has found wide adoption after initial hesitation. At server-side, there are more than five million domains signed with DNSSEC. A portion of them is insecure due to insufficient cryptographic key lengths or broken due to maintenance failures. At client-side, we have observed a worldwide increase of DNSSEC validation over the last three years, though not necessarily on the last mile. -
Popping the Bitcoin Bubble: an Application of Log-Periodic Power Law Modeling to Digital Currency
Popping the Bitcoin Bubble: An application of log-periodic power law modeling to digital currency Alec MacDonell University of Notre Dame April 1, 2014 Abstract The year 2013 witnessed a remarkable increase in public interest and awareness of digital currencies such as Bitcoin. Hailed by some as the currency of the future, these “cryptocurrencies” have gained notoriety for their use in online black markets, but have yet to gain widespread acceptance. Given their novelty and lack of central regulating authorities, digital currencies experience high volatility and uncertainty regarding value. Taking Bitcoin as a representative example, this paper first uses autoregressive moving average (ARMA) functions to explain trading values, then applies log-periodic power law (LPPL) models in an attempt to predict crashes. The results of ARMA modeling show that Bitcoin values react to the CBOE Volatility Index, suggesting that a primary force currently driving Bitcoin values is speculation by investors looking outside traditional markets. In addition, the LPPL models accurately predict ex-ante the crash that occurred in December 2013, making LPPL models a potentially valuable tool for understanding bubble behavior in digital currencies. *I would like to thank Steven Lugauer for advising me during the research and writing of this paper. His instruction and guidance has been invaluable. Table of Contents 3 Introduction 6 Background 8 Data and ARMA Model Construction 17 Financial Bubbles 20 The LPPL Model 26 Application to December 2013 Bitcoin Crash 29 Conclusions 33 References 2 1 Introduction Traditional instruction in economics teaches that currency takes one of two forms – commodity money or fiat money. -
CS4700/CS5700 Fundamentals of Computer Networks
CS4700/CS5700 Fundamentals of Computer Networks Lecture 17: Domain Name System Slides used with permissions from Edward W. Knightly, T. S. Eugene Ng, Ion Stoica, Hui Zhang Alan Mislove amislove at ccs.neu.edu Northeastern1 University Human Involvement • Just like your friend needs to tell you his phone number for you to call him • Somehow, an application needs to know the IP address of the communication peer • There is no magic, some out-of-band mechanism is needed – Word of mouth – Read it in the advertisement in the paper – Etc. • But IP addresses are bad for humans to remember and tell each other • So need names that makes some sense to humans Alan Mislove amislove at ccs.neu.edu Northeastern2 University Internet Names & Addresses • Names: e.g. www.rice.edu – human-usable labels for machines – conforms to “organizational” structure • Addresses: e.g. 128.42.247.150 – router-usable labels for machines – conforms to “network” structure • How do you map from one to another? – Domain Name System (DNS) Alan Mislove amislove at ccs.neu.edu Northeastern3 University DNS: History • Initially all host-addess mappings were in a file called hosts.txt (in /etc/hosts) – Changes were submitted to SRI by email – New versions of hosts.txt ftp’d periodically from SRI – An administrator could pick names at their discretion – Any name is allowed: eugenesdesktopatrice • As the Internet grew this system broke down because: – SRI couldn’t handled the load – Hard to enforce uniqueness of names – Many hosts had inaccurate copies of hosts.txt • Domain Name System (DNS) was born Alan Mislove amislove at ccs.neu.edu Northeastern4 University Basic DNS Features • Hierarchical namespace – as opposed to original flat namespace • Distributed storage architecture – as opposed to centralized storage (plus replication) • Client--server interaction on UDP Port 53 – but can use TCP if desired Alan Mislove amislove at ccs.neu.edu Northeastern5 University Naming Hierarchy root edu com gov mil org net uk fr etc.