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Digital Fountain Erasure-Recovery in Bittorrent
UNIVERSITÀ DEGLI STUDI DI BERGAMO Facoltà di Ingegneria Corso di Laurea Specialistica in Ingegneria Informatica Classe n. 35/S – Sistemi Informatici Digital Fountain Erasure Recovery in BitTorrent: integration and security issues Relatore: Chiar.mo Prof. Stefano Paraboschi Correlatore: Chiar.mo Prof. Andrea Lorenzo Vitali Tesi di Laurea Specialistica Michele BOLOGNA Matricola n. 56108 ANNO ACCADEMICO 2007 / 2008 This thesis has been written, typeset and prepared using LATEX 2". Printed on December 5, 2008. Alla mia famiglia “Would you tell me, please, which way I ought to go from here?” “That depends a good deal on where you want to get to,” said the Cat. “I don’t much care where —” said Alice. “Then it doesn’t matter which way you go,” said the Cat. “— so long as I get somewhere,” Alice added as an explanation. “Oh, you’re sure to do that,” said the Cat, “if you only walk enough.” Lewis Carroll Alice in Wonderland Acknowledgments (in Italian) Ci sono molte persone che mi hanno aiutato durante lo svolgimento di questo lavoro. Il primo ringraziamento va ai proff. Stefano Paraboschi e Andrea Vitali per la disponibilità, la competenza, i consigli, la pazienza e l’aiuto tecnico che mi hanno saputo dare. Grazie di avermi dato la maggior parte delle idee che sono poi confluite nella mia tesi. Un sentito ringraziamento anche a Andrea Rota e Ruben Villa per l’aiuto e i chiarimenti che mi hanno gentilmente fornito. Vorrei ringraziare STMicroelectronics, ed in particolare il gruppo Advanced System Technology, per avermi offerto le infrastrutture, gli spa- zi e tutto il necessario per svolgere al meglio il mio periodo di tirocinio. -
Osiris Secure Social Backup
James Bown Osiris Secure Social Backup Computer Science Tripos, Part II Project St John’s College May 17, 2011 The cover page image is the hieroglyphic representation of the Ancient Egyptian god of the underworld, Osiris. His legend tells of how he was torn into pieces and later resurrected by bringing them together once again. The font used to generate this image was used with the kind permission of Mark-Jan Nederhof (http://www.cs.st-andrews.ac.uk/~mjn/). Proforma Name: James Bown College: St John’s College Project Title: Osiris – Secure Social Backup Examination: Computer Science Tripos, Part II Project Date: May 17, 2011 Word Count: 11,841 Project Originator: Malte Schwarzkopf Supervisor: Malte Schwarzkopf Original Aims of the Project To produce a distributed system enabling mutually beneficial peer-to-peer backup between groups of friends. Each user provides storage space on their personal machine for other users to back up their data. In exchange, they have the right to back up their own files onto their friends’ machines. I focus on the challenges of space efficient distribution and fault tolerant retrieval of data. The use of convergent encryption and a strict security policy maintains confidentiality of data. Work Completed All success criteria specified in the proposal have been not only fulfilled, but exceeded. I have implemented a concurrent and distributed peer-to-peer backup system that is able to send, retrieve and remove files from the network, recover from node failure or loss, and provide high security supporting convergent encryption. Finally, I have completed a number of additional extensions. -
Henry Jenkins Convergence Culture Where Old and New Media
Henry Jenkins Convergence Culture Where Old and New Media Collide n New York University Press • NewYork and London Skenovano pro studijni ucely NEW YORK UNIVERSITY PRESS New York and London www.nyupress. org © 2006 by New York University All rights reserved Library of Congress Cataloging-in-Publication Data Jenkins, Henry, 1958- Convergence culture : where old and new media collide / Henry Jenkins, p. cm. Includes bibliographical references and index. ISBN-13: 978-0-8147-4281-5 (cloth : alk. paper) ISBN-10: 0-8147-4281-5 (cloth : alk. paper) 1. Mass media and culture—United States. 2. Popular culture—United States. I. Title. P94.65.U6J46 2006 302.230973—dc22 2006007358 New York University Press books are printed on acid-free paper, and their binding materials are chosen for strength and durability. Manufactured in the United States of America c 15 14 13 12 11 p 10 987654321 Skenovano pro studijni ucely Contents Acknowledgments vii Introduction: "Worship at the Altar of Convergence": A New Paradigm for Understanding Media Change 1 1 Spoiling Survivor: The Anatomy of a Knowledge Community 25 2 Buying into American Idol: How We are Being Sold on Reality TV 59 3 Searching for the Origami Unicorn: The Matrix and Transmedia Storytelling 93 4 Quentin Tarantino's Star Wars? Grassroots Creativity Meets the Media Industry 131 5 Why Heather Can Write: Media Literacy and the Harry Potter Wars 169 6 Photoshop for Democracy: The New Relationship between Politics and Popular Culture 206 Conclusion: Democratizing Television? The Politics of Participation 240 Notes 261 Glossary 279 Index 295 About the Author 308 V Skenovano pro studijni ucely Acknowledgments Writing this book has been an epic journey, helped along by many hands. -
Defense Against the Dark Arts of Copyright Trolling Matthew As G
Loyola University Chicago, School of Law LAW eCommons Faculty Publications & Other Works 2018 Defense Against the Dark Arts of Copyright Trolling Matthew aS g Jake Haskell Follow this and additional works at: https://lawecommons.luc.edu/facpubs Part of the Civil Procedure Commons, and the Intellectual Property Law Commons Defense Against the Dark Arts of Copyright Trolling Matthew Sag &Jake Haskell * ABSTRACT: In this Article, we offer both a legal and a pragmaticframework for defending against copyright trolls. Lawsuits alleging online copyright infringement by John Doe defendants have accounted for roughly half of all copyright casesfiled in the United States over the past threeyears. In the typical case, the plaintiffs claims of infringement rely on a poorly substantiatedform pleading and are targeted indiscriminately at noninfringers as well as infringers. This practice is a subset of the broaderproblem of opportunistic litigation, but it persists due to certain unique features of copyright law and the technical complexity of Internet technology. The plaintiffs bringing these cases target hundreds or thousands of defendants nationwide and seek quick settlements pricedjust low enough that it is less expensive for the defendant to pay rather than to defend the claim, regardless of the claim's merits. We report new empirical data on the continued growth of this form of copyright trolling in the United States. We also undertake a detailed analysis of the legal andfactual underpinnings of these cases. Despite theirunderlying weakness, plaintiffs have exploited information asymmetries, the high cost of federal court litigation, and the extravagant threat of statutory damages for copyright infringement to leverage settlementsfrom the guilty and the innocent alike. -
A Privacy-Preserving Decentralized Storage with Payments Based on a Blockchain
A Privacy-preserving Decentralized Storage with Payments Based on a Blockchain Dissertation zur Erlangung des Doktorgrades Dr. rer. nat. der Fakultat¨ fur¨ Ingenieurwissenschaften, Informatik und Psychologie der Universitat¨ Ulm Henning Johannes Gustav Kopp aus Villingen-Schwenningen 2018 Institut f¨urVerteilte Systeme Universit¨atUlm, Deutschland Amtierender Dekan: Prof. Maurits Ortmanns Gutachter: Prof. Frank Kargl Gutachter: Prof. Frederik Armknecht Tag der Promotion: 20.12.2018 Summary Recently, the paradigm of cloud storage has seen wide acceptance in industry and for personal use. One of its core principles is to outsource storage, such that users can be billed flexibly by their actual demand. However, outsourcing storage such as private data or business secrets leads to privacy problems, as control over the data is lost to the storage provider. This is intensified by the fact that often privacy is considered only as an afterthought in these systems and not integrated into the design from the beginning. Privacy-preserving alternatives to these centralized cloud storage providers are peer-to-peer systems like Freenet or GNUnet. In these systems, participants can donate storage to other users of the system. Privacy plays a vital role in these systems, as, e. g., participants are unable to access data of other users if they are not authorized to do so, even if the data of the other users resides on their own hard disk. However, these decentralized systems suffer from limited contribution due to a lack of incentives to participate. Naively enhancing these systems with the possibility of payments such that storage providers can earn money, infringes privacy, since tracing of payment flows provides links between users and their storage providers. -
Connectivity Properties of Mainline Bittorrent DHT Nodes
IEEE P2P'09 - Sept. 9-11, 2009 Connectivity Properties of Mainline BitTorrent DHT Nodes Raul Jimenez Flutra Osmani Bj¨orn Knutsson Royal Institute of Technology (KTH) ICT/TSLAB Stockholm, Sweden {rauljc, flutrao, bkn}@kth.se Abstract raises some concerns about the scalability and resilience of the technology. The birth and evolution of Peer-to-Peer (P2P) protocols Our work is part of the P2P-Next[1] project, which is have, for the most part, been about peer discovery. Napster, supported by many partners including the EBU2 who claims one of the first P2P protocols, was basically FTP/HTTP to have more than 650 million viewers weekly. In the face plus a way of finding hosts willing to send you the file. Since of such load, scalability and resilience become vital compo- then, both the transfer and peer discovery mechanisms have nents of the underlying technology. improved, but only recently have we seen a real push to In BitTorrent, content is distributed in terms of objects, completely decentralized peer discovery to increase scal- consisting of one or more files, and these objects are de- ability and resilience. scribed by a torrent-file. The clients (peers)participatingin Most such efforts are based on Distributed Hash Tables the distribution of one such object form a swarm. (DHTs), with Kademlia being a popular choice of DHT im- Aswarmiscoordinatedbyatracker,whichkeepstrack plementation. While sound in theory, and performing well of every peer in the swarm. In order to join a swarm, a peer in simulators and testbeds, the real-world performance of- must contact the tracker, which registers the new peer and ten falls short of expectations. -
The Perfect Way by Anna Bonus Kingsford and Edward Maitland the Perfect Way Or the Finding of Christ
The Perfect Way by Anna Bonus Kingsford and Edward Maitland The Perfect Way or The Finding of Christ by Anna Bonus Kingsford and Edward Maitland Published in 1888 Boston, Mass.: ESOTERIC PUBLISHING COMPANY, 478 Shawmut Avenue. (Revised and Enlarged Edition.) Page 1 The Perfect Way by Anna Bonus Kingsford and Edward Maitland AUTHORS’ EXPLANATION These lectures were delivered in London, before a private audience, in the months of May, June, and July, 1881. The changes made in this edition calling for indication, are, – the substitution of another Lecture for No. V., and consequent omission of most of the plates; the rewriting, in the whole or part, of paragraphs 6 - 8 and 28 in No. I.; 34 - 36 in No. II.; 5 - 8, 12, 13, 22, 23, 42, 43, 54, and 55, in No. IX. (the latter paragraphs being replaced by a new one); the lengthening of Appendices II, and VI; the addition of a new Part to Appendix XIII. (formerly No. IX); and the substitution of eight new Appendices for Nos:. VII., and VIII. The alterations involve no change or withdrawal of doctrine, but only extension of scope, amplification of statement, or modification of expression. A certain amount of repetition being inseparable from the form adopted, – that of a series of expository lectures, each requiring to be complete in itself, – and the retention of that form being unavoidable, – no attempt has been made to deal with the instances in which repetition occurs. PREFACE TO THE AMERICAN EDITION In presenting an American edition of THE PERFECT WAY, or, The Finding of Christ, to the reading and inquiring public, we have been actuated by the conviction that a comprehensive textbook of the “new views,” or the restored wisdom and knowledge of the ages regarding religion or the perfect life, was imperatively required, wherein the subject was treated in a manner luminous, instructive, and entertaining, and which, without abridgement, or inferiority of material or workmanship, could yet be sold at a price that would bring the work within the means of the general public. -
Kademlia on the Open Internet
Kademlia on the Open Internet How to Achieve Sub-Second Lookups in a Multimillion-Node DHT Overlay RAUL JIMENEZ Licentiate Thesis Stockholm, Sweden 2011 TRITA-ICT/ECS AVH 11:10 KTH School of Information and ISSN 1653-6363 Communication Technology ISRN KTH/ICT/ECS/AVH-11/10-SE SE-164 40 Stockholm ISBN 978-91-7501-153-0 SWEDEN Akademisk avhandling som med tillstånd av Kungl Tekniska högskolan framlägges till offentlig granskning för avläggande av Communication Systems fredag den 9 december 2011 klockan 10.00 i C2, Electrum, Kungl Tekniska högskolan, Forum, Isafjordsgatan 39, Kista. © Raul Jimenez, December 2011 This work is licensed under a Creative Commons Attribution 2.5 Sweden License. http://creativecommons.org/licenses/by/2.5/se/deed.en Tryck: Universitetsservice US AB iii Abstract Distributed hash tables (DHTs) have gained much attention from the research community in the last years. Formal analysis and evaluations on simulators and small-scale deployments have shown good scalability and per- formance. In stark contrast, performance measurements in large-scale DHT overlays on the Internet have yielded disappointing results, with lookup latencies mea- sured in seconds. Others have attempted to improve lookup performance with very limited success, their lowest median lookup latency at over one second and a long tail of high-latency lookups. In this thesis, the goal is to to enable large-scale DHT-based latency- sensitive applications on the Internet. In particular, we improve lookup la- tency in Mainline DHT, the largest DHT overlay on the open Internet, to identify and address practical issues on an existing system. -
Privacy Enhancing Technologies for the Internet III: Ten Years Later
Privacy Enhancing Technologies for the Internet III: Ten Years Later Ian Goldberg David R. Cheriton School of Computer Science University of Waterloo Waterloo, ON [email protected] 1 Introduction In 1997 with Wagner and Brewer, and again in 2002, we looked at the then-current state of privacy-enhancing technologies (PETs) for the Internet. [27, 26] Now, in 2007, we take a third look. Technologies to help users maintain their privacy online are as important today as ever before—if not more so. Identity theft is the fastest-growing crime in the US today [47] and it is all too easy for would-be identity thieves to harvest personal information from the online trails Internet users leave every day. Losses of large databases of personal information are an almost daily occurrence [2]; for example, retailers’ servers are penetrated [44], databases are traded between government and private companies [36] and laptops containing social security numbers are stolen [35]. In 1997, we discussed the dossier effect: all available information about a person gets cross-referenced, and the resulting dossier ends up being used for many purposes, lawful and not. This practice has expanded over the years; the companies that compile and sell these dossiers are known as data brokers. Choicepoint is a prime example—in 2005, this data broker sold dossiers on over 150,000 Americans to a group of criminals. [10] The PETs we discuss here give people a way to control how much of their personal information is revealed when they use the Internet. By controlling the spread of this information, they can limit the size of the data brokers’ dossiers about them. -
Bittorrent and Fountain Codes: Friends Or Foes?
BitTorrent and fountain codes: friends or foes? Salvatore Spoto, Rossano Gaeta, Marco Grangetto, Matteo Sereno Dipartimento di informatica Università di Torino Peer to peer and file sharing applications Peer to peer paradigm has a huge diffusion nowadays [1] It can be employed for a lot of different applications: • File sharing: BitTorrent [2][3] , eDonkey, eMule, DC++ • Video Streaming : SopCast, PPLive, PPStream • Distribuited portals: Osiris • Others: Skype, Sciencenet, Spotify BitTorrent is doubtless the reference architecture for file sharing BitTorrent protocol 1 BitTorrent adopts a multi-part download scheme: File’s pieces Piece’s blocks b1 b2 b3 b4 … • The file is divided into pieces, each piece into blocks. • Peers are synchronized between them at piece level. • Each client knows what pieces have been completely downloaded from his neighbors. • Peers exchange between them piece’s blocks BitTorrent protocol 2: rarest first and tit for tat Main BitTorrent’s strategies: - Tit-for-Tat: assures reciprocity between downloading and uploading rates. - Rarest first: assures a fair distribution of file’s pieces Note that only complete pieces can be shared and distributed Many research works claim that BitTorrent has near-optimal performance [4] [5] [6] Flash crowd, high churn rates Some phenomena can cripple BitTorrent performance: • Flash crowd: many peer join or leave the network at the same time • High churn rates: peers join and leave the network at high rates Example of simulated population's dynamics in a network affected by flash • Many peer leave the overlay network at crowd and high Churn rates. the same time Modifying BitTorrent protocol 1: Luby-transform codes LT codes [7][8] are a class a fountain codes that use simple XOR operations to encode and decode the message. -
Towards a Basic DHT Service: Analyzing Network Characteristics of a Widely Deployed DHT
Towards a Basic DHT Service: Analyzing Network Characteristics of a Widely Deployed DHT Konrad Junemann,¨ Philipp Andelfinger, and Hannes Hartenstein Steinbuch Centre for Computing (SCC) Karlsruhe Institute of Technology (KIT), Germany {juenemann, hartenstein}@kit.edu, philipp.andelfi[email protected] Abstract—Distributed Hash Tables (DHTs) prove valuable for DHT-based applications without having to worry about DHT distributed architectures by providing distributed information deployment, running OpenDHT nodes on PlanetLab entailed lookup, routing, and data storage while promising good scala- two disadvantages: first, the DHT did not scale with growing bility and robustness at the same time. From this point of view, a DHT could be seen as a basic service that can be used to numbers of clients as the DHT consisted of a fixed number of build distributed applications. Whereas today no widely deployed (centrally administered) PlanetLab nodes only and clients did and publicly accessible basic DHT service exists and thus DHT- not contribute to the DHT. Second, the OpenDHT nodes had based applications have to deploy their very own DHT networks, to be maintained. DHTs consisting of millions of peers are formed by file sharing Simultaneously, the file-sharing community started lever- clients. Although the interfaces of typical DHTs used for file sharing are too narrow, a basic DHT service could probably be aging DHTs to replace centralized components within their created by bundling a suitable client implementation with file file sharing networks. Therefore, DHT clients were bundled sharing software. In this paper, we evaluate whether a basic with file sharing clients, resulting in widely deployed DHTs DHT service could suit the needs of DHT-based applications introduced by clients like Azureus [31], eDonkey or the Bit- in terms of stability, number of participating peers, the peers’ Torrent Mainline client [13]. -
A Pragmatic Analysis of Peer to Peer Networks and Protocols for Security and Confidentiality
http://www.ijccr.com International Manuscript ID : ISSN2249054X-V2I6M7-112012 VOLUME 2 ISSUE 6 November 2012 A PRAGMATIC ANALYSIS OF PEER TO PEER NETWORKS AND PROTOCOLS FOR SECURITY AND CONFIDENTIALITY Anil Saroliya 1, Upendra Mishra 2, Ajay Rana 3 1Department of Computer Science, Amity University Rajasthan, Jaipur, India; 2Department of Mathematics, Amity University Rajasthan, Jaipur, India; 3Department of Computer Science, Amity University Utter Pradesh, Noida, India; ABSTRACT The internet as we ought to understand it is a dramatized environment that links together various information, networks and communication channels. However, the bitter truth lies in the fact that the Internet has largely grown into a drone that lacks essential centralized control. Putting into simpler terms, with the day by day growth of the Internet, it is simply beginning to lack any hierarchical control. With this growth, comes the need of large scale data distribution, content sharing and multicasting applications. In other words, the need of the hour lays in extensive use of Peer-to-Peer (P2P) networks. The P2P networks are loaded with the abilities to provide many handy features such as selection of most accurately reachable peers, powerful search mechanisms or location of data together with hierarchical name stay. The P2P networks have the special ability to organize and handle self-framed routing architecture that also helps in measuring massive scalability and hence provides a robust and efficient load balance of the world wide network or simply the Internet. Despite the numerous merits of P2P Networks over the near obsolete client- server mechanisms, there have also been some shortcomings in the same.