11 research outputs found

    Spying the World from your Laptop -- Identifying and Profiling Content Providers and Big Downloaders in BitTorrent

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    This paper presents a set of exploits an adversary can use to continuously spy on most BitTorrent users of the Internet from a single machine and for a long period of time. Using these exploits for a period of 103 days, we collected 148 million IPs downloading 2 billion copies of contents. We identify the IP address of the content providers for 70% of the BitTorrent contents we spied on. We show that a few content providers inject most contents into BitTorrent and that those content providers are located in foreign data centers. We also show that an adversary can compromise the privacy of any peer in BitTorrent and identify the big downloaders that we define as the peers who subscribe to a large number of contents. This infringement on users' privacy poses a significant impediment to the legal adoption of BitTorrent

    BitTorrent Sync: Network Investigation Methodology

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    The volume of personal information and data most Internet users find themselves amassing is ever increasing and the fast pace of the modern world results in most requiring instant access to their files. Millions of these users turn to cloud based file synchronisation services, such as Dropbox, Microsoft Skydrive, Apple iCloud and Google Drive, to enable "always-on" access to their most up-to-date data from any computer or mobile device with an Internet connection. The prevalence of recent articles covering various invasion of privacy issues and data protection breaches in the media has caused many to review their online security practices with their personal information. To provide an alternative to cloud based file backup and synchronisation, BitTorrent Inc. released an alternative cloudless file backup and synchronisation service, named BitTorrent Sync to alpha testers in April 2013. BitTorrent Sync's popularity rose dramatically throughout 2013, reaching over two million active users by the end of the year. This paper outlines a number of scenarios where the network investigation of the service may prove invaluable as part of a digital forensic investigation. An investigation methodology is proposed outlining the required steps involved in retrieving digital evidence from the network and the results from a proof of concept investigation are presented.Comment: 9th International Conference on Availability, Reliability and Security (ARES 2014

    Compromising Tor Anonymity Exploiting P2P Information Leakage

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    Privacy of users in P2P networks goes far beyond their current usage and is a fundamental requirement to the adoption of P2P protocols for legal usage. In a climate of cold war between these users and anti-piracy groups, more and more users are moving to anonymizing networks in an attempt to hide their identity. However, when not designed to protect users information, a P2P protocol would leak information that may compromise the identity of its users. In this paper, we first present three attacks targeting BitTorrent users on top of Tor that reveal their real IP addresses. In a second step, we analyze the Tor usage by BitTorrent users and compare it to its usage outside of Tor. Finally, we depict the risks induced by this de-anonymization and show that users' privacy violation goes beyond BitTorrent traffic and contaminates other protocols such as HTTP

    Why are they hiding ? Study of an Anonymous File Sharing System

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    International audienceThis paper characterizes a recently proposed anonymous file sharing system, OneSwarm. This characterisation is based on measurement of several aspects of the OneSwarm system such as the nature of the shared and searched content and the geolocation and number of users. Our findings indicate that, as opposed to common belief, there is no significant difference in downloaded content between this system and the classical BitTorrent ecosystem. We also found that a majority of users appears to be located in countries where anti-piracy laws have been recently adopted and enforced (France, Sweden and U.S). Finally, we evaluate the level of privacy provided by OneSwarm, and show that, although the system has strong overall privacy, a collusion attack could potentially identify content providers

    I Know Where You are and What You are Sharing: Exploiting P2P Communications to Invade Users' Privacy

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    In this paper, we show how to exploit real-time communication applications to determine the IP address of a targeted user. We focus our study on Skype, although other real-time communication applications may have similar privacy issues. We first design a scheme that calls an identified targeted user inconspicuously to find his IP address, which can be done even if he is behind a NAT. By calling the user periodically, we can then observe the mobility of the user. We show how to scale the scheme to observe the mobility patterns of tens of thousands of users. We also consider the linkability threat, in which the identified user is linked to his Internet usage. We illustrate this threat by combining Skype and BitTorrent to show that it is possible to determine the file-sharing usage of identified users. We devise a scheme based on the identification field of the IP datagrams to verify with high accuracy whether the identified user is participating in specific torrents. We conclude that any Internet user can leverage Skype, and potentially other real-time communication systems, to observe the mobility and file-sharing usage of tens of millions of identified users.Comment: This is the authors' version of the ACM/USENIX Internet Measurement Conference (IMC) 2011 pape

    Vulnรฉrabilitรฉs de la DHT de BitTorrent & Identification des comportements malveillants dans KAD

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    Le prรฉsent dรฉlivrable prรฉsente les rรฉsultats des travaux menรฉs durant les six premiers mois (T0+6) du projet GIS 3SGS ACDAP2P dont l'objectif est de proposer une architecture collaborative pour la dรฉtection d'attaques dans les rรฉseaux pair ร  pair. Nous dรฉtaillons dans ce rapport nos travaux concernant l'identification des comportements malveillants affectant le rรฉseaux KAD (tรขche T2) ainsi que l'identification des vulnรฉrabilitรฉs affectant la DHT du rรฉseau BitTorrent (tรขche T3) qui sont au coeur du projet ACDAP2P. Pour introduire nos travaux, nous prรฉsentons tout d'abord leur contexte ainsi qu'une taxonomie des diffรฉrentes attaques pouvant affecter les DHT.. Notre premiรจre contribution montre ร  travers plusieurs expรฉriences que des failles de sรฉcuritรฉ permettent la rรฉalisation d'attaques efficaces pouvant altรฉrer le bon fonctionnement de la DHT de BitTorrent. En prenant pour cas d'รฉtude le rรฉseau P2P KAD, nous recensons ensuite les pairs suspects en utilisant deux approches de dรฉtection et montrons ainsi que des milliers de contenus du rรฉseau sont attaquรฉs durant nos mesures. Finalement, nous constatons l'รฉphรฉmรฉritรฉ de certains attaquants dans le rรฉseau

    BitTorrent ์‹œ์Šคํ…œ์—์„œ ์ปจํ…ํŠธ ๋ฒˆ๋“ค๋ง ๋ฐ ๋ฐฐํฌ

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    ํ•™์œ„๋…ผ๋ฌธ (๋ฐ•์‚ฌ)-- ์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› : ์ „๊ธฐยท์ปดํ“จํ„ฐ๊ณตํ•™๋ถ€, 2013. 2. ์ตœ์–‘ํฌ.BitTorrent๋Š” ์ปจํ…ํŠธ ๊ณต์œ ์— ์‚ฌ์šฉ๋˜๋Š” ๊ฐ€์žฅ ์ธ๊ธฐ์žˆ๋Š” ์ธํ„ฐ๋„ท ์†Œํ”„ํŠธ์›จ์–ด์ด๋‹ค. BitTorrent๊ฐ€ ๋„๋ฆฌ ์‚ฌ์šฉ๋จ์— ๋”ฐ๋ผ, ์—ฐ๊ตฌ์ž๋“ค์€ BitTorrent์˜ ์ฒ˜๋ฆฌ๋Ÿ‰, ๊ณต์ •์„ฑ, ์ธ์„ผํ‹ฐ๋ธŒ์™€ ๊ฐ™์€ ์ด์Šˆ์— ๋Œ€ํ•ด ์—ฐ๊ตฌํ•ด ์™”๊ณ , ์ด๋Ÿฌํ•œ ์—ฐ๊ตฌ๋“ค์€ BitTorrent ์„ฑ๋Šฅ๊ณผ ๊ด€๋ จ๋œ ๊ฐ€์น˜์žˆ๋Š” ๊ฒฐ๊ณผ๋“ค์„ ๋ณด์—ฌ์ฃผ์—ˆ๋‹ค. ํ•˜์ง€๋งŒ ๋Œ€๋ถ€๋ถ„์˜ ์—ฐ๊ตฌ์—์„œ๋Š”, BitTorrent์—์„œ์˜ ์ปจํ…ํŠธ ๋ฒˆ๋“ค๋ง ๋ฐ ๋ฐฐํฌ ์ „๋žต๊ณผ ๊ด€๋ จํ•ด์„œ (1) BitTorrent ๋ฐฐํฌ์ž๊ฐ€ ํŒŒ์ผ์„ ์–ด๋–ค ๋ชฉ์ ์œผ๋กœ ์–ด๋–ป๊ฒŒ ๋ฒˆ๋“ค ํ•˜๋Š”์ง€์™€ (2) BitTorrent์˜ ๋ฐฐํฌ์ž๋“ค์ด ๊ทธ๋“ค์˜ ๋ชฉ์ ์„ ์„ฑ์ทจํ•˜๊ธฐ ์œ„ํ•ด ์–ด๋– ํ•œ ์ „๋žต๋“ค์„ ์‚ฌ์šฉํ•˜๋Š”์ง€ ๋“ฑ์— ๋Œ€ํ•ด ๋‹ค๋ฃจ๊ณ  ์žˆ์ง€ ์•Š๋‹ค. ๋ณธ ํ•™์œ„ ๋…ผ๋ฌธ์—์„œ๋Š”, ์•ž์„œ ์–ธ๊ธ‰ํ•œ ๋ฌธ์ œ๋“ค์„ ์ธก์ •๋œ ๋ฐ์ดํ„ฐ๋ฅผ ๋ฐ”ํƒ•์œผ๋กœ ์กฐ์‚ฌํ•˜๊ธฐ ์œ„ํ•ด์„œ, BitTorrent ํฌํƒˆ์ค‘ ๊ฐ€์žฅ ํฐ ๊ทœ๋ชจ์ธ The Pirate Bay (TPB)์— ๋Œ€ํ•œ ์ข…ํ•ฉ์ ์ธ ์ธก์ • ์—ฐ๊ตฌ๋ฅผ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ์ธก์ •๋œ ๋ฐ์ดํ„ฐ์…‹์€ 12๋งŒ๊ฐœ์˜ ํ† ๋ŸฐํŠธ์™€ 1600๋งŒ๋ช…์˜ ์‚ฌ์šฉ์ž๋กœ ๊ตฌ์„ฑ๋˜์—ˆ๊ณ , ์ปจํ…ํŠธ ๋ฐฐํฌ์ž๋ฅผ (i) ๊ฐ€์งœ ๋ฐฐํฌ์ž, (ii) ์ด์œค์ถ”๊ตฌ ๋ฐฐํฌ์ž, (iii) ์ดํƒ€์  ๋ฐฐํฌ์ž ์„ธ๊ฐ€์ง€ ์ข…๋ฅ˜๋กœ ๋ถ„๋ฅ˜ํ•˜์—ฌ ์—ฐ๊ตฌ๋ฅผ ์ง„ํ–‰ํ•˜์˜€๋‹ค. ๋˜ํ•œ ์˜ํ™”, TV, ์„ฑ์ธ๋ฌผ, ์Œ์•…, ์‘์šฉํ”„๋กœ๊ทธ๋žจ, ๊ฒŒ์ž„, ์ „์ž์ฑ…๊ณผ ๊ฐ™์€ ์ปจํ…ํŠธ ์นดํ…Œ๊ณ ๋ฆฌ์— ๋”ฐ๋ผ ๋ฒˆ๋“ค๋ง๊ณผ ์ปจํ…ŒํŠธ ๋ฐฐํฌ ํ˜„ํ™ฉ์ด ์–ด๋–ป๊ฒŒ ๋˜๋Š”์ง€ ์กฐ์‚ฌํ•˜์˜€๋‹ค. ์ฒซ๋ฒˆ์งธ๋กœ, ํ† ๋ŸฐํŠธ์˜ ๊ตฌ์กฐ์  ํŒจํ„ด๊ณผ ์Šค์™ ์ฐธ์—ฌ์ž์˜ ํ–‰๋™ ํŒจํ„ด์„ ํŒŒ์•…ํ•˜๊ธฐ ์œ„ํ•ด ์ปจํ…ํŠธ ๋ฒˆ๋“ค๋ง๊ณผ ๊ด€๋ จ๋œ ํ˜„ํ™ฉ์„ ์กฐ์‚ฌํ•˜์˜€๋‹ค. ํŠน๋ณ„ํžˆ, (1) ์–ผ๋งˆ๋‚˜ ์ปจํ…ํŠธ ๋ฒˆ๋“ค๋ง์ด ๋„๋ฆฌ ์‚ฌ์šฉ๋˜๋Š”๊ฐ€, (2) ์–ด๋–ค ํŒŒ์ผ๋“ค์ด ์–ด๋–ป๊ฒŒ ํ† ๋ŸฐํŠธ๋กœ ๋ฒˆ๋“ค๋˜๋Š”๊ฐ€, (3) ์™œ ๋ฐฐํฌ์ž๋“ค์ด ํŒŒ์ผ์„ ๋ฒˆ๋“คํ•ด์„œ ์‚ฌ์šฉํ•˜๋Š”๊ฐ€, (4) ์‚ฌ์šฉ์ž๋“ค์ด ๋ฒˆ๋“ค๋œ ํŒŒ์ผ๋“ค์„ ์–ด๋–ป๊ฒŒ ๋‹ค์šด๋กœ๋“œ ๋ฐ›๋Š”๊ฐ€์— ์ดˆ์ ์„ ๋งž์ถ”์–ด ์—ฐ๊ตฌ๋ฅผ ์ˆ˜ํ–‰ํ•˜์˜€๋‹ค. ์ธก์ •๊ฒฐ๊ณผ 72% ์ด์ƒ์˜ ํ† ๋ŸฐํŠธ๋“ค์ด ์—ฌ๋Ÿฌ๊ฐœ์˜ ํŒŒ์ผ๋กœ ๊ตฌ์„ฑ๋˜์–ด ์žˆ๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๊ณ , ์ด๊ฒƒ์€ ๋ฒˆ๋“ค์ด BitTorrent์˜ ํŒŒ์ผ ๊ณต์œ ๋ฅผ ์œ„ํ•ด ๋„๋ฆฌ ์‚ฌ์šฉ๋˜๊ณ  ์žˆ์Œ์„ ๋ณด์—ฌ์ค€๋‹ค. ๊ทธ๋ฆฌ๊ณ  ๊ฒฝ์ œ์ ์ธ ์ด๋“์„ ์œ„ํ•ด ์›น์‚ฌ์ดํŠธ๋ฅผ ๊ด‘๊ณ ํ•˜๋Š” ์ด์œค์ถ”๊ตฌ ๋ฐฐํฌ์ž๋“ค์ด ๋ฒˆ๋“ค์„ ์„ ํ˜ธํ•˜์—ฌ ์‚ฌ์šฉํ•˜๋Š” ๊ฒฝํ–ฅ์ด ์žˆ์Œ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค. ๋˜ํ•œ ๋ฒˆ๋“ค๋œ ํ† ๋ŸฐํŠธ์˜ ๋Œ€๋ถ€๋ถ„์˜ ํŒŒ์ผ(94%)์ด ์‚ฌ์šฉ์ž๋“ค์— ์˜ํ•ด ์„ ํƒ๋˜๊ณ , ๋ฒˆ๋“ค๋œ ํ† ๋ŸฐํŠธ๊ฐ€ ๋ฒˆ๋“ค์ด ์•„๋‹Œ ํ† ๋ŸฐํŠธ๋ณด๋‹ค ํ‰๊ท ์ ์œผ๋กœ ๋” ์ธ๊ธฐ๊ฐ€ ์ข‹์Œ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค. ์ „์ฒด์ ์œผ๋กœ, ํ† ๋ŸฐํŠธ์˜ ๊ตฌ์กฐ์  ํŒจํ„ด๊ณผ ์Šค์™ ์ฐธ์—ฌ์ž์˜ ํŠน์ง•์€ ์ปจํ…ํŠธ์˜ ์นดํ…Œ๊ณ ๋ฆฌ ์ข…๋ฅ˜์— ๋”ฐ๋ผ์„œ, ๊ทธ๋ฆฌ๊ณ  ๋ฒˆ๋“ค๋œ ํ† ๋ŸฐํŠธ์ธ์ง€ ๋ฒˆ๋“ค๋˜์ง€ ์•Š์€ ํ† ๋ŸฐํŠธ์ธ์ง€์— ๋”ฐ๋ผ์„œ ์ฃผ๋ชฉํ• ๋งŒํ•œ ์ฐจ์ด์ ์ด ์žˆ์Œ์„ ๋ฐœ๊ฒฌํ•  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ๋‹ค์Œ์œผ๋กœ, ์‚ฌํšŒ๊ฒฝ์ œ์  ๊ด€์ ์—์„œ BitTorrent์˜ ์ปจํ…ํŠธ ๋ฐฐํฌ ํŒจํ„ด์„ (1) ๋ฐฐํฌ์ž์— ์˜ํ•ด์„œ ํŒŒ์ผ์ด ์–ด๋–ป๊ฒŒ ๋ฐฐํฌ๋˜๋Š”๊ฐ€, (2) ๊ฐ ๋ฐฐํฌ์ž๋“ค์€ ์–ด๋–ค ์ „๋žต๋“ค์„ ์‚ฌ์šฉํ•˜๋Š”๊ฐ€, (3) ๋ฐฐํฌ ์ „๋žต๋“ค์ด ์–ผ๋งˆ๋‚˜ ํšจ๊ณผ๊ฐ€ ์žˆ๋Š”๊ฐ€์˜ ์ธก๋ฉด์—์„œ ์กฐ์‚ฌํ•˜์˜€๋‹ค. ์ธก์ •๊ฒฐ๊ณผ ์ƒ๋‹นํ•œ ์–‘์˜ ํŠธ๋ž˜ํ”ฝ(61%)์ด ๊ฐ€์งœ ํ† ๋ŸฐํŠธ๋ฅผ ๋‹ค์šด๋ฐ›์„ ๋•Œ ๋ฐœ์ƒํ•˜๊ณ  ์žˆ๋Š” ๊ฒƒ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๊ณ , ์ด๋Š” ๋งŽ์€ ์–‘์˜ ์ธํ„ฐ๋„ท ํŠธ๋ž˜ํ”ฝ์ด ๋ถˆํ•„์š”ํ•˜๊ฒŒ ๋‚ญ๋น„๋˜๊ณ  ์žˆ์Œ์„ ๋ณด์—ฌ ์ฃผ๋Š” ๊ฒƒ์ด๋‹ค. ๋”ฐ๋ผ์„œ ๋ณธ ์ธก์ • ๊ฒฐ๊ณผ๋กœ๋ถ€ํ„ฐ ์•Œ ์ˆ˜ ์žˆ๋Š” ๊ฐ€์งœ ๋ฐฐํฌ์ž๋“ค์˜ ๋ฐฐํฌ ํŒจํ„ด์„ ๊ณ ๋ คํ•ด์„œ TPB์˜ ๊ฐ€์งœ ๋ฐฐํฌ์ž๋ฅผ ๊ฑธ๋Ÿฌ๋‚ผ ์ˆ˜ ์žˆ๋Š” ๋ฐฉ๋ฒ•์„ ์ œ์•ˆํ•˜์˜€๊ณ , ์ œ์•ˆ๋œ ๋ฐฉ๋ฒ•์ด ์ „์ฒด ๋‹ค์šด๋กœ๋“œ ํŠธ๋ž˜ํ”ฝ์˜ 45% ๊ฐ€๋Ÿ‰์„ ์ค„์ผ ์ˆ˜ ์žˆ์Œ์„ ๋ณด์—ฌ ์ฃผ์—ˆ๋‹ค. ๋˜ํ•œ ์ด์œค์ถ”๊ตฌ ๋ฐฐํฌ์ž๋“ค์€ ๊ทธ๋“ค์˜ ์ˆ˜์ต๋ชจ๋ธ(์˜ˆ๋ฅผ ๋“ค์–ด, ๊ฐœ์ธ ํŠธ๋ž˜์ปค ์‚ฌ์ดํŠธ์— ์ƒˆ๋กœ์šด ์‚ฌ์šฉ์ž๋ฅผ ์˜์ž…ํ•˜๋Š” ๊ฒƒ์ด๋‚˜ ์‚ฌ๋žŒ๋“ค์ด ์‚ฌ์ง„๊ณผ ์—ฐ๊ฒฐ๋œ URL ๋งํฌ๋ฅผ ํด๋ฆญํ•˜๋„๋ก ํ•˜๋Š” ๊ฒƒ)์— ๋”ฐ๋ผ ๋‹ค๋ฅธ ๋ฐฐํฌ ์ „๋žต์„ ์ด์šฉํ•˜๊ณ  ์žˆ์Œ์„ ์•Œ ์ˆ˜ ์žˆ์—ˆ๋‹ค.BitTorrent is one of the most popular applications for sharing contents over the Internet. The huge success of BitTorrent has attracted the research community to investigate BitTorrent's behavior in terms of throughput, fairness, and incentive issues, revealing valuable insights into the performance aspects of BitTorrent. However, most of these studies paid little attention to understand content bundling and publishing strategies in BitTorrent from the following perspectives: (1) how, and for what purposes, are constituent files bundled by BitTorrent publishers? and (2) what strategies are adopted by BitTorrent publishers to achieve their goals? To answer these questions with data from a large-scale BitTorrent system, we conduct comprehensive measurements on one of the largest BitTorrent portals: the Pirate Bay (TPB). From the datasets of the 120 K torrents and 16 M peers, we classify BitTorrent publishers into three types: (i) fake publishers, (ii) profit-driven publishers, and (iii) altruistic publishers. Throughout this dissertation, we investigate the current practice of bundling and publishing across different content categories: Movie, TV, Porn, Music, Application, Game, and E-book. We first investigate the current practice of content bundling to understand the structural patterns of torrents and the participant behaviors of swarms. In particular, we focus on: (1) how prevalent content bundling is, (2) how and what files are bundled into torrents, (3) what motivates publishers to bundle files, and (4) how peers access the bundled files. We find that over 72% of BitTorrent torrents contain multiple files, which indicates that bundling is widely used for file sharing. We reveal that profit-driven BitTorrent publishers who promote their own web sites for financial gains like advertising tend to prefer to use the bundling. We also observe that most files (94%) in a bundle torrent are selected by users and the bundle torrents are more popular than the single (or non-bundle) ones on average. Overall, there are notable differences in the structural patterns of torrents and swarm characteristics (i) across different content categories and (ii) between single and bundle torrents. We next investigate the current practice of content publishing in BitTorrent from a socio-economic point of view, by unraveling (1) how files are published by publishers, (2) what strategies are adopted by publishers, and (3) how effective those strategies are. We show that a significant amount of traffic (61%) of BitTorrent has been generated (i.e., unnecessarily wasted) to download fake torrents. Therefore, we suggest a method to filter out fake publishers on TPB by considering their distinct publishing patterns learned from our measurement study, and show that the proposed method can reduce around 45% of the total download traffic. We also reveal that profit-driven publishers adopt different publishing strategies according to their revenue models (e.g., advertising private tracker sites to attract potential new members, or exposing image URLs to make people click the URL links).Abstract i I. Introduction 1 II. Related Work 5 2.1 Multi-torrent Systems 5 2.2 Bundling in BitTorrent 6 2.3 Bundling in Economics 7 2.4 Content publishing in BitTorrent 7 III. Methodology 9 3.1 Measurement Methodology 9 3.2 Publisher Classification 11 IV. Bundling Practice in BitTorrent: What, How, and Why 14 4.1 Introduction 14 4.2 Datasets 16 4.2.1 Torrent Datasets 17 4.2.2 Swarm Datasets 17 4.3 Single vs. Bundle 18 4.3.1 Bundling is widespread 18 4.3.2 How files are bundled 20 4.4 Main File Analysis in Bundling 27 4.4.1 Identifying Main Files 28 4.4.2 Constituents of Bundle-k 29 4.5 Publisher Analysis 32 4.5.1 Contribution of Top-20 Publishers 33 4.5.2 Cross-category Publishing of Top-20 Publishers 39 4.6 User Access Pattern Analysis 40 4.6.1 Popularity Analysis 40 4.6.2 Availability Analysis 43 4.6.3 The Number of Files Requested by Users in a Bundle Torrent 44 4.6.4 Swarm Behaviors versus Bundle-k 47 4.7 Discussions 50 V. Content Publishing Practice in BitTorrent 52 5.1 Introduction 52 5.2 The Number of Published Torrents 54 5.3 Publishers Strategies 58 5.3.1 Lifetime of Publishers and their Publishing Rates 59 5.3.2 Content Categories 60 5.3.3 Advertising Strategies of Profit-driven Publishers 63 5.4 Downloaders Behavior 64 5.5 Implications on Publishers Strategies 69 5.5.1 Fake Publishers 69 5.5.2 Profit-driven Publishers 71 VI. Summary & Future Work 73 Bibliography 75 Korean Abstract 80Docto
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