DOCSLIB.ORG

A Weather Tracker for Internet Censorship

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Weather Tracker for Internet Censorship This paper will appear at the 14th ACM Conference on Computer and Communications Security, Oct. 29-Nov. 2, 2007 ConceptDoppler: A Weather Tracker for Internet Censorship Jedidiah R. Crandall Daniel Zinn Michael Byrd Univ. of New Mexico Univ. of California at Davis Univ. of California at Davis [email protected] [email protected] [email protected] Earl Barr Rich East Univ. of California at Davis Independent Researcher [email protected] [email protected] ABSTRACT The text of this paper has passed across many Internet routers on its way to the reader, but some routers will not pass it along unfet- Everybody talks about the weather but nobody does tered because of censored words it contains. We present two sets anything about it. of results: 1) Internet measurements of keyword filtering by the Great “Firewall” of China (GFC); and 2) initial results of using la- Charles Dudley Warner (1829–1900) tent semantic analysis as an efficient way to reproduce a blacklist of censored words via probing. Our Internet measurements suggest that the GFC’s keyword fil- Categories and Subject Descriptors tering is more a panopticon than a firewall, i.e., it need not block K.4.m [Computers and Society]: Miscellaneous every illicit word, but only enough to promote self-censorship. China’s largest ISP, ChinaNET, performed 83.3% of all filtering of our probes, and 99.1% of all filtering that occurred at the first General Terms hop past the Chinese border. Filtering occurred beyond the third Experimentation, human factors, legal aspects, measurement, secu- hop for 11.8% of our probes, and there were sometimes as many as rity 13 hops past the border to a filtering router. Approximately 28.3% of the Chinese hosts we sent probes to were reachable along paths that were not filtered at all. While more tests are needed to provide Keywords a definitive picture of the GFC’s implementation, our results dis- LSA, latent semantic analysis, latent semantic indexing, firewall prove the notion that GFC keyword filtering is a firewall strictly at ruleset discovery, Internet censorship, Great Firewall of China, In- the border of China’s Internet. ternet measurement, panopticon, ConceptDoppler, keyword filter- While evading a firewall a single time defeats its purpose, it ing, blacklist would be necessary to evade a panopticon almost every time. Thus, in lieu of evasion, we propose ConceptDoppler, an architecture for maintaining a censorship “weather report” about what keywords 1. INTRODUCTION are filtered over time. Probing with potentially filtered keywords is Societies have always divided speech into objectionable and per- arduous due to the GFC’s complexity and can be invasive if not missible categories. By facilitating the flow of information, the done efficiently. Just as an understanding of the mixing of gases Internet has sharpened this debate over categorization. Inspired by preceded effective weather reporting, understanding of the rela- initial work [8] on the Great Firewall of China (GFC)’s keyword tionship between keywords and concepts is essential for tracking filtering mechanism, we sought a better understanding of its im- Internet censorship. We show that LSA can effectively pare down plementation and found it to be not a firewall at all, but rather a a corpus of text and cluster filtered keywords for efficient probing, panopticon where the presence of censorship, even if easy to evade, present 122 keywords we discovered by probing, and underscore promotes self-censorship. the need for tracking and studying censorship blacklists by discov- Clayton et al. [8] provide more details about how the GFC’s ering some surprising blacklisted keywords such as l (con- keyword filtering operates. GFC routers scan for keywords in GET version rate), K— (Mein Kampf), and ýE0(ÑfT requests or HTML responses (and possibly in other protocols) that (International geological scientific federation (Beijing)). are on a blacklist of keywords considered sensitive. If a packet con- taining a keyword passes through one of these routers, the router sends one or more reset (RST) packets to both the source and desti- nation IP addresses of the packet in an attempt to reset the connec- Permission to make digital or hard copies of all or part of this work for tion. personal or classroom use is granted without fee provided that copies are While we do not wish to take sides in any particular Internet not made or distributed for profit or commercial advantage and that copies censorship debate in a technical paper, much of this paper is written bear this notice and the full citation on the first page. To copy otherwise, to to develop a technology to perform surveillance on a censorship republish, to post on servers or to redistribute to lists, requires prior specific mechanism. However, the technical material in this paper can aid permission and/or a fee. CCS’07, October 29–November 2, 2007, Alexandria, Virginia, USA. those on either side of a censorship debate. We probed the GFC to Copyright 2007 ACM 978-1-59593-703-2/07/0011 ...$5.00. find out the locations of the filtering routers and how reliably they perform the filtering. Two insights came from the results of these censorship is used. A censorship weather report would give policy probes, one that motivates a research focus on surveillance rather makers an exact record of how a censorship mechanism was used than evasion, and a second that motivates doing the surveillance and how it was implemented over a period of time. For example, efficiently: policy makers cannot ask important questions such as why øÕ b'Õ (Judicial yuan grand justices) or sVëH (Virgin • Contrary to common belief, the filtering mechanism is not prostitution law case) were filtered at a particular place and time a firewall that peremptorily filters all offending packets at without first knowing what was filtered. the international gateway of the Internet between China and As a first step toward an Internet censorship weather report, we other countries. explore the keyword filtering mechanism of the GFC. Keyword fil- tering is an important tool for censorship, and a complete picture • Probing is very arduous because of the complexity of the of the blacklist of keywords that are filtered, over time and for dif- GFC. ferent geographic locations within a specific country, can prove in- The first of these insights motivates the need for surveillance. valuable to those who wish to understand that government’s use of Our results suggest that only roughly one fourth of the filtering oc- keyword-based Internet censorship. curs at the international gateway, with a much larger constituent of 1.1 Keyword-based Censorship the filtering occurring several hops into China, and some filtering occurring as many as 13 hops past the border. In fact, depending The ability to filter keywords is an effective tool for governments on the path packets take from our source point into China, 28.3% that censor the Internet. Numerous techniques comprise censor- of the IP addresses we probed were reachable without traversing ship, including IP address blocking, DNS redirection, and a myriad a GFC router, therefore no filtering at all occurred for these des- of legal restrictions, but the ability to filter keywords in URL re- tinations. Combined with the fact that a single ISP did a dispro- quests or HTML responses allows a high granularity of control that portionate amount of the filtering, our results show that the GFC’s achieves the censor’s goals with low cost. implementation is much more centralized at the AS-level1 than had As pointed out by Danezis and Anderson [10], censorship is an economic activity. The Internet has economic benefits and more been previously thought. Even on routes where there are filtering 2 routers, the filtering is inconsistent and tends to allow many pack- blunt methods of censorship than keyword filtering , such as block- ets through during busy network periods. While evading a firewall ing entire web sites or services, decrease those benefits. There is a single time defeats the firewall, it would be necessary to evade a also a political cost of more blunt censorship mechanisms due to panopticon almost every time to defeat its purpose. This is why we the dissatisfaction of those censored. For example, while the Chi- propose ConceptDoppler as a first step towards an Internet cen- nese government has shut down e-mail service for entire ISPs, tem- sorship weather report. porarily blocked Internet traffic from overseas universities [5], and The second of these insights motivates the need for efficient could conceivably stop any flow of information [14], they have also probing. As pointed out by the Open Net Initiative, “China’s so- been responsive to complaints about censorship from Chinese cit- phisticated filtering system makes testing its blocking difficult” [3]. izens, recently allowing access to the Chinese language version of Not only is the filtering heterogeneous in its implementation [8] and Wikipedia [18, 19], before restricting access again [20]. Keyword- inconsistent both during busy periods and depending on the path, based censorship gives censoring governments the ability to control but there is also much noise in such forms as RSTs generated by Internet content in a less draconian way than other technologies, misconfigured routers and hosts, inconsistent paths because of traf- making censorship more effective in achieving their goals. fic shaping, IP tunnelling, Internet Exchange Points (IXPs) [25], To motivate the need to track an Internet keyword blacklist over and routers that do not conform to the RFC for handling TTLs. time, we must first refute the notion that censorship is always try- We can send candidate words through a filtering router and receive ing in vain to stop a flood of ideas.
Load more

Recommended publications
  • Germany, International Justice and the 20Th Century
    Paul Betts Dept .of History University of Sussex NOT TO BE QUOTED WITHOUT PERMISSION OF THE AUTHOR: DRAFT VERSION: THE FINAL DRAFT OF THIS ESSAY WILL APPEAR IN A SPECIAL ISSUE OF HISTORY AND MEMORY IN APRIL, 2005, ED. ALON CONFINO Germany, International Justice and the 20th Century The turning of the millennium has predictably spurred fresh interest in reinterpreting the 20th century as a whole. Recent years have witnessed a bountiful crop of academic surveys, mass market picture books and television programs devoted to recalling the deeds and misdeeds of the last one hundred years. It then comes as no surprise that Germany often figures prominently in these new accounts. If nothing else, its responsibility for World War I, World War II and the Holocaust assures its villainous presence in most every retrospective on offer. That Germany alone experienced all of the modern forms of government in one compressed century – from constitutional monarchy, democratic socialism, fascism, Western liberalism to Soviet-style communism -- has also made it a favorite object lesson about the so-called Age of Extremes. Moreover, the enduring international influence of Weimar culture, feminism and the women’s movement, social democracy, post-1945 economic recovery, West German liberalism, environmental politics and most recently pacifism have also occasioned serious reconsideration of the contemporary relevance of the 20th century German past. Little wonder that several commentators have gone so far as to christen the “short twentieth century” between 1914 and 1989 as really the “German century,” to the extent that German history is commonly held as emblematic of Europe’s 20th century more generally.1 Acknowledging Germany’s central role in 20th century life has hardly made things easy for historians, however.
    [Show full text]
  • Threat Modeling and Circumvention of Internet Censorship by David Fifield
    Threat modeling and circumvention of Internet censorship By David Fifield A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Computer Science in the Graduate Division of the University of California, Berkeley Committee in charge: Professor J.D. Tygar, Chair Professor Deirdre Mulligan Professor Vern Paxson Fall 2017 1 Abstract Threat modeling and circumvention of Internet censorship by David Fifield Doctor of Philosophy in Computer Science University of California, Berkeley Professor J.D. Tygar, Chair Research on Internet censorship is hampered by poor models of censor behavior. Censor models guide the development of circumvention systems, so it is important to get them right. A censor model should be understood not just as a set of capabilities|such as the ability to monitor network traffic—but as a set of priorities constrained by resource limitations. My research addresses the twin themes of modeling and circumvention. With a grounding in empirical research, I build up an abstract model of the circumvention problem and examine how to adapt it to concrete censorship challenges. I describe the results of experiments on censors that probe their strengths and weaknesses; specifically, on the subject of active probing to discover proxy servers, and on delays in their reaction to changes in circumvention. I present two circumvention designs: domain fronting, which derives its resistance to blocking from the censor's reluctance to block other useful services; and Snowflake, based on quickly changing peer-to-peer proxy servers. I hope to change the perception that the circumvention problem is a cat-and-mouse game that affords only incremental and temporary advancements.
    [Show full text]
  • The German Netzdg As Role Model Or Cautionary Tale? Implications for the Debate on Social Media Liability
    Fordham Intellectual Property, Media and Entertainment Law Journal Volume 31 XXXI Number 4 Article 4 2021 The German NetzDG as Role Model or Cautionary Tale? Implications for the Debate on Social Media Liability Patrick Zurth Ludwig Maximilian University of Munich (LMU), [email protected] Follow this and additional works at: https://ir.lawnet.fordham.edu/iplj Part of the International Law Commons, and the Internet Law Commons Recommended Citation Patrick Zurth, The German NetzDG as Role Model or Cautionary Tale? Implications for the Debate on Social Media Liability, 31 Fordham Intell. Prop. Media & Ent. L.J. 1084 (2021). Available at: https://ir.lawnet.fordham.edu/iplj/vol31/iss4/4 This Article is brought to you for free and open access by FLASH: The Fordham Law Archive of Scholarship and History. It has been accepted for inclusion in Fordham Intellectual Property, Media and Entertainment Law Journal by an authorized editor of FLASH: The Fordham Law Archive of Scholarship and History. For more information, please contact [email protected]. The German NetzDG as Role Model or Cautionary Tale? Implications for the Debate on Social Media Liability Cover Page Footnote Dr. iur., LL.M. (Stanford). Postdoctoral Fellow at the Chair for Private Law and Intellectual Property Law with Information- and IT-Law (GRUR-chair) (Prof. Dr. Matthias Leistner, LL.M. (Cambridge)) at Ludwig Maximilian University of Munich, Germany. Thanks to Professor David Freeman Engstrom, Abhilasha Vij, Jasmin Hohmann, Shazana Rohr, and the editorial board of the Fordham Intellectual Property, Media and Entertainment Law Journal for helpful comments and assistance.
    [Show full text]
  • The Byline of Europe: an Examination of Foreign Correspondents' Reporting from 1930 to 1941
    Illinois State University ISU ReD: Research and eData Theses and Dissertations 3-8-2017 The Byline of Europe: An Examination of Foreign Correspondents' Reporting from 1930 to 1941 Kerry J. Garvey Illinois State University, [email protected] Follow this and additional works at: https://ir.library.illinoisstate.edu/etd Part of the European History Commons, Journalism Studies Commons, and the Mass Communication Commons Recommended Citation Garvey, Kerry J., "The Byline of Europe: An Examination of Foreign Correspondents' Reporting from 1930 to 1941" (2017). Theses and Dissertations. 671. https://ir.library.illinoisstate.edu/etd/671 This Thesis is brought to you for free and open access by ISU ReD: Research and eData. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of ISU ReD: Research and eData. For more information, please contact [email protected]. THE BYLINE OF EUROPE: AN EXAMINATION OF FOREIGN CORRESPONDENTS’ REPORTING FROM 1930 TO 1941 Kerry J. Garvey 133 Pages This thesis focuses on two of the largest foreign correspondents’ networks the one of the Chicago Tribune and New York Times- in prewar Europe and especially in Germany, thus providing a wider perspective on the foreign correspondents’ role in news reporting and, more importantly, how their reporting appeared in the published newspaper. It provides a new, broader perspective on how foreign news reporting portrayed European events to the American public. It describes the correspondents’ role in publishing articles over three time periods- 1930 to 1933, 1933-1939, and 1939 to 1941. Reporting and consequently the published paper depended on the correspondents’ ingenuity in the relationship with the foreign government(s); their cultural knowledge; and their gender.
    [Show full text]
  • Towards a History of the Serial Killer in German Film History
    FOCUS ON GERMAN STUDIES 14 51 “Warte, warte noch ein Weilchen...” – Towards a History of the Serial Killer in German Film History JÜRGEN SCHACHERL Warte, warte noch ein Weilchen, dann kommt Haarmann auch zu dir, mit dem Hackehackebeilchen macht er Leberwurst aus dir. - German nursery rhyme t is not an unknown tendency for dark events to be contained and to find expression in nursery rhymes and children’s verses, such as I the well-known German children’s rhyme above. At first instance seemingly no more than a mean, whiny playground chant, it in fact alludes to a notorious serial killer who preyed on young male prostitutes and homeless boys. Placed in this context, the possible vulgar connotations arising from Leberwurst become all the more difficult to avoid recognizing. The gravity of these events often becomes drowned out by the sing-song iambics of these verses; their teasing melodic catchiness facilitates the overlooking of their lyrical textual content, effectively down-playing the severity of the actual events. Moreover, the containment in common fairy tale-like verses serves to mythologize the subject matter, rendering it gradually more fictitious until it becomes an ahistorical prototype upon a pedestal. Serial killer and horror films have to an arguably large extent undergone this fate – all too often simply compartmentalized in the gnarly pedestal category of “gore and guts” – in the course of the respective genres’ development and propagation, particularly in the American popular film industry: Hollywood. The gravity and severity of the serial murder phenomenon become drowned in an indifferent bloody splattering of gory effects.
    [Show full text]
  • Introducing the Norwegian Forum for Freedom of Expression's
    66th IFLA Council and General Conference - IFLA/FAIFE Open Session - August 16, 2000, Jerusalem, Israel By Mette Newth, project leader 0. Introduction Allow me to first express my pleasure at being here. The original idea of the Bibliotheca Alexandrina database project was conceived by the Norwegian Forum for Freedom of Expression in Spring of 1997, and strongly supported by Mr. Frode Bakken, then Chairman of The Norwegian Library Association. Right from the start we hoped for co-operation with IFLA and the then emerging IFLA/FAIFE Office. All the more pleasurable to be here today, knowing that IFLA through the IFLA/FAIFE Office will be a close partner in the future development of this unique and ambitious project. A project aiming to collect and make electronically available bibliographic data on all books and newspapers censored world wide through the ages, as well as literature published on freedom of expression and censorship. Libraries remain the true memory of humanity. Our project is created in honour of the vast number of men and women whose writings for various reasons were censored through human history, - many of their books now lost forever – their ideas and thoughts in no way available to the public. Thus we regard the database also as a monument to the fundamental right of free access to information. Let me briefly introduce the Norwegian Forum for Freedom of Expression: founded in 1995 by 15 major Norwegian organisations within the media field as an independent centre of documentation and information. NFFE still remains a fairly unique constellation of organisations, representing as it does authors and translators, booksellers, libraries and publishers, journalists and editors as well as HR organisations such as P.E.N and the Norwegian Helsinki Committee.
    [Show full text]
  • Censorship and Subversion in German No-Budget Horror Film Kai-Uwe Werbeck
    The State vs. Buttgereit and Ittenbach: Censorship and Subversion in German No-Budget Horror Film Kai-Uwe Werbeck IN THE LATE 1980S AND EARLY 1990S, WEST GERMAN INDIE DIRECTORS released a comparatively high number of hyper-violent horror films, domestic no-budget productions often shot with camcorders. Screened at genre festivals and disseminated as grainy VHS or Betamax bootlegs, these films constitute anomalies in the history of German postwar cinema where horror films in general and splatter movies in particular have been rare, at least up until the 2000s.1 This article focuses on two of the most prominent exponents of these cheap German genre flicks: Jörg Buttgereit’s controversial and highly self- reflexive NekRomantik 2 (1991) and Olaf Ittenbach’s infamous gore-fest The Burning Moon (1992), both part of a huge but largely obscure underground culture of homebrew horror. I argue that both NekRomantik 2 and The Burning Moon—amateurish and raw as they may appear—successfully reflect the state of non-normative filmmaking in a country where, according to Germany’s Basic Law, “There shall be no censorship.”2 Yet, the nation’s strict media laws—tied, in particular, to the Jugendschutz (protection of minors)—have clearly limited the horror genre in terms of production, distribution, and reception. In this light, NekRomantik 2 and The Burning Moon become note- worthy case-studies that in various ways query Germany’s complex relation to the practice of media control after 1945. Not only do both films have an inter- esting history with regard to the idiosyncratic form of censorship practiced in postwar (West) Germany, they also openly engage with the topic by reacting to the challenges of transgressive art in an adverse cultural climate.
    [Show full text]
  • International Enemy Images in Digital Games
    Who Are the Enemies? The Visual Framing of Enemies in Digital Games1 BRANDON VALERIANO Reader School of Law and Politics Cardiff University PHILIP HABEL Lecturer School of Social and Politics Sciences University of Glasgow 1 We thank Andrew Stevens, Lauren Pascu, and Eduard Alveraz for research assistance. We thank Andrew Stevens, Dan Nexon, Tom Apperly, Matt Barr, Lindsay Hoffman, Greg Perreault, and Daniel Franklin for comments and suggestions. Digital games are among the most popular forms of entertainment media. Despite their ubiquity, the fields of political science and International Relations and political communication have generally overlooked the study of digital games. We take up this void by examining the international enemies depicted in combat games---specifically, first person shooter (FPS) games—which can speak to the process in the construction of international threats in society. Our review of framing the enemy gleans perspectives from multiple disciplines including International Relations, political communication, and digital gaming. Our empirical analysis traces the evolution of images in digital games from 2001 to 2013 to reveal the identity of the enemies and protagonists, and to examine the context of the game—including the setting for where each game takes place. We find that Russians are a popular form of enemy in FPS games even after considering terrorists as a broad category. Our review of the literature and our empirical analysis together present a foundation for the future study of digital games as a process of framing of enemies and transmission of threats. 2 Today digital games are ubiquitous---on our phones, tablets, laptops, and on dedicated gaming consoles and personal computers.2 Games offer an experience that is distinct and novel from other forms of entertainment in that they are possible avenues of transmission of attitudes and beliefs.
    [Show full text]
  • MEADES Phd Thesis
    PLAYING AGAINST THE GRAIN RHETORICS OF COUNTERPLAY IN CONSOLE BASED FIRST-PERSON SHOOTER VIDEOGAMES A thesis submitted for the degree of Doctor of Philosophy By Alan Frederick Meades School of Arts, Brunel University February 2013 1 ABSTRACT Counterplay is a way of playing digital games that opposes the encoded algorithms that define their appropriate use and interaction. Counterplay is often manifested within the social arena as practices such as the creation of incendiary user generated content, grief-play, cheating, glitching, modding, and hacking. It is deemed damaging to normative play values, to the experience of play, and detrimental to the viability of videogames as mainstream entertainment products. Counterplay is often framed through the rhetoric of transgression as pathogen, as a hostile, infectious, threatening act. Those found conducting it are subject to a range of punishments ranging from expulsion from videogames to criminal conviction. Despite the steps taken to manage counterplay, it occurs frequently within contemporary videogames causing significant disruption to play and necessitating costly remedy. This thesis argues that counterplay should be understood as a practice with its own pleasures and justifying rhetorics that problematise the rhetoric of pathogen and attenuate the threat of penalty. Despite the social and economic significance of counterplay upon contemporary videogames, relatively little is known of the practices conducted by counterplayers, their motivations, or the rhetorics that they deploy to justify and contextualise their actions. Through the use of ethnographic approaches, including interview and participant observation, alongside the identification and application of five popular rhetorics of transgression, this study aims to expose the meanings and complexities of contemporary counterplay.
    [Show full text]
  • Wagner for the ~'Aster Ol..E£.Ience
    AN AESTliACT OF' THE. THESIS OF' Richard L..!- Wagner for the ~'aster oL..e£.ience _ in Soc~l SCience£ presented on July 18, 1977 Title: __ The Allied tiilitary Government ~;ostal -1m Abstract approved: I~ With the collapse of the German government in May 1945, the victorious Allied powers became the rulers of Cermany. It was necessary to take control of all aspects of civil govern­ ment immediately. A vital part of this ~overnment was the postal system. The Allied ~ilitary Government set up the communication network needed in several steps, beginning with limited local services, and extending through special services until, on April 1, 1946, international mail was again permitted to and from Germany. This thesis traces this pattern of reestablishment. T,ocal ser­ vices and problems are examined, the special postal cards for displaced persons, civilian internees, prisoners of war, and members of the German Wehrmacht are explained, and the steps leading to the reopening of international mail are detailed. Close examination and attention is paid to the problems of censorship and screening of mail. The disposal of mail im­ pounded at the end of the war and transfer of mail between the different occupation zones and how these challenges were met by censorship authorities are presented in detail. The repatriation of displaced persons, civilian internees, prisoner of war, armed forces personnel, and other refugees through special communication programs is traced step by step, with attention focused on the many aspects of these programs. Finally, an examination of the special problem of postal issues, authorized, provisional, and unauthorized, is presented.
    [Show full text]
  • A Taxonomy of Internet Censorship and Anti- Censorship
    A Taxonomy of Internet Censorship and Anti- Censorship Draft Version December 31, 2010 Christopher S. Leberknight Mung Chiang Princeton University Princeton University Department of Electrical Engineering Department of Electrical Engineering [email protected] [email protected] Harold Vincent Poor Felix Wong Princeton University Princeton University Department of Electrical Engineering Department of Electrical Engineering [email protected] [email protected] ABSTRACT – Internet is supposed to be born free, yet it is censored almost everywhere, and severely censored in a few countries. The tug-of-war on the Internet between censors and anti-censors is intensifying. This survey presents a taxonomy on the principles, techniques, and technologies of Internet censorship and anti-censorship. It highlights the challenges and opportunities in anti-censorship research, and outlines a historical account via the lenses of news coverage in the past decade. I. INTRODUCTION Internet is supposed to be born free, yet it is censored almost everywhere, and severely censored in a few countries. Censorship is defined as the institution, system or practice of reading communication and deleting material considered sensitive or harmful [1]. Throughout history, various methods of censorship have been used to reinforce specific religious and political agendas. Technology has often served as a major obstacle and catalyst for mandating censorship. Even though technological advancement often ameliorates the inefficiencies and limitations of the past, it also can precipitate unforeseen consequences. The invention of the printing press in Europe in the 15th century is a prime example. The printing press not only increased the spread of information and knowledge but it also increased the practice and frequency of censorship.
    [Show full text]
  • Obfuscating Network Traffic to Circumvent Censorship
    Obfuscating Network Traffic to Circumvent Censorship Awn Umar MEng Mathematics and Computer Science University of Bristol May 21, 2021 Abstract This report explores some techniques used to censor information in transit on the Internet. The attack surface of the Internet is explained as well as how this affects the potential for abuse by powerful nation state adversaries. Previous research and existing traffic fingerprinting and obfuscation techniques are discussed. Rosen, a modular and flexible proxy tunnel, is introduced and evaluated against state-of-the- art DPI engines, as are some existing censorship circumvention tools. Rosen is also successfully tested from behind the Great Firewall in China. 1 Contents 1 Contextual Background 3 1.1 Information on the Internet.....................................3 1.2 Security of Internet Protocols....................................3 1.3 Exploitation of the Internet by Nation States...........................5 1.3.1 Mass Surveillance.......................................5 1.3.2 Censorship..........................................6 1.4 Ethic of Responsibility........................................7 2 Project Definition 7 2.1 Aim and Objectives.........................................7 2.2 Scope.................................................8 2.3 Vocabulary..............................................8 3 Adversarial Model 8 4 Traffic Identification Methods 11 4.1 Endpoint-Based Filtering...................................... 11 4.2 Traffic Fingerprinting........................................ 13 5 Network
    [Show full text]