DOCSLIB.ORG

The Pynchon Gate

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Pynchon Gate The Pynchon Gate A Secure Method of Pseudonymous Mail Retrieval Len Sassaman Bram Cohen Nick Mathewson Katholieke Universiteit Leuven BitTorrent The Free Haven Project [email protected] [email protected] [email protected] ABSTRACT ter [48] or Mixminion [22]) to send authenticated requests to We describe the Pynchon Gate, a practical pseudonymous a nym server, which delivers outgoing messages to the email message retrieval system. Our design uses a simple distributed- network and handles administrative commands. The nym trust private information retrieval protocol to prevent ad- server also receives incoming messages and passes them to a versaries from linking recipients to their pseudonyms, even collator component, which encrypts the messages and peri- when some of the infrastructure has been compromised. This odically packages them into regular batches. These batches approach resists global traffic analysis significantly better are then replicated at a number of distributor servers, which than existing deployed pseudonymous email solutions, at the use a private information retrieval protocol to allow nym cost of additional bandwidth. We examine security concerns owners to receive mail while maintaining unlinkability be- raised by our model, and propose solutions. tween a message and its recipient. 1.0.1 Goals. Categories and Subject Descriptors First, our design must be secure: we want the Pynchon C.2.4 [Distributed Systems]: Client/server Gate to resist active and passive attacks at least as well as General Terms the state of the art for forward message anonymity. Thus, we should try to protect users’ identities from a global eaves- Design, Security dropper for as long as possible; to hinder active attackers Keywords who can delay, delete, or introduce traffic; and to resist an attacker who has compromised some (but not all) of the anonymity, mix networks, private information retrieval servers on the network. In order to provide security, however, we must ensure that 1. INTRODUCTION the system is deployable and usable: since anonymity and Pseudonymous messaging services allow users to send mes- pseudonymity systems hide users among each other, fewer sages that originate at a pseudonymous address (or “nym”) users means less protection [1]. Thus, we should handle node unlinked to the user, and to receive messages sent to that failure without loss of mail; we must not require more band- address, without allowing an attacker to deduce which users width than volunteer servers can provide or users are willing are associated with which pseudonyms. These systems can to use; and we should not require a complicated interface. be used for parties to communicate without revealing their identities, or can be used as a building-block for other sys- 1.0.2 In this paper. tems that need a bi-directional anonymous communication We begin in Section 2 with a discussion of related work, channel, such as Free Haven [27]. But, as we will argue be- and an overview of known attacks against existing pseudo- low, most existing deployed solutions are either vulnerable nymity systems. (To motivate our work, Subsection 4.2 to traffic analysis or require unacceptably large amounts of presents new analysis on the effectiveness of passive traf- bandwidth and storage as the number of users and volume fic analysis against current reply-block based nym servers.) of traffic increase. Section 3 presents the Pynchon Gate in more detail, describ- We propose the Pynchon Gate, a design that uses private ing its organization, design rationales, and network formats. information retrieval (PIR) [13] primitives to build a secure, We describe our simple PIR protocol in subsection 3.4.1. In fault-tolerant pseudonymous mail retrieval system. Section 4 we analyze security, and in Section 5 we discuss In our system, pseudonymous users (or “nym holders”) optimizations and compare our performance to that of other use an existing anonymous email network (such as Mixmas- pseudonymous message systems. We close with an evalua- tion of our design in Section 6. Permission to make digital or hard copies of all or part of this work for 2. BACKGROUND personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies Here we present a brief outline of existing pseudonymity bear this notice and the full citation on the first page. To copy otherwise, to solutions and discuss their limitations and attacks against republish, to post on servers or to redistribute to lists, requires prior specific them. permission and/or a fee. WPES’05, November 7, 2005, Alexandria, Virginia, USA. Copyright 2005 ACM 1-59593-228-3/05/0011 ...$5.00. 2.1 Related Work messages share the same anonymity set, and recent work First, we discuss existing designs for pseudonymous mes- has been done by Danezis and Laurie on attack-resistant sage delivery. Many assume the existence of a “forward” anonymous packet formats suitable for reply messages [23]. anonymous channel that a sender can use to send a mes- However, since reply blocks are still used, reliability issues sage to a known recipient while preventing the recipient, remain: if any given node in the pre-selected SURB’s path the infrastructure, and any attackers from knowing who is is defunct during the interval in which the mail is to be communicating with whom. Currently deployed designs are delivered, the mail is lost. Reply block systems are also based on Chaum’s mix [12] architecture, and include the susceptible to intersection attacks [8]: a global observer can Mixmaster [48] and Mixminion [22] anonymous remailer net- collect data on who is sending and receiving mail, and given works. It is trivial to use these systems to send pseudony- enough time and data, can reliably determine who is talking mous messages: the sender can make an anonymous message to whom [19]. pseudonymous by signing it with a public key associated with her pseudonym. Thus, these designs focus on how to 2.1.3 Network-level client anonymity. receive messages sent to a pseudonymous address. The ZKS Freedom Network [9] provided anonymous ac- Other descriptions of the use of PIR in preserving recipi- cess to a POP3 server [47], enabling its users to maintain ent anonymity have been independently proposed but not pseudonyms using standard email protocols. Freedom was deployed. Earlier work by Jim McCoy describes a simi- discontinued due to high operating expenses, especially in lar architecture to the Pynchon Gate, but does not use an bandwidth. Other network-level anonymity systems, such as information-theoretic primitive for preserving privacy [46]. Pipenet [18], Onion Routing [33], the Java Anon Proxy [7], Independent work by Cooper and Birman [15] describes a or Tor [28], could be used in much the same fashion; un- PIR-based message service for mobile computing systems, fortunately, they face the same barriers to widespread de- and Berthold, et al. have presented work [6] which shows ployment [32]. Attempts to address the practical barriers to that simple optimizations to the PIR protocol are possible. deployment of low-latency anonymity systems have resulted in designs which are at greater risk to traffic analysis meth- 2.1.1 Reply blocks and return addresses. ods such as end-to-end timing attacks [21, 20, 49, 25] It is In 1981, Chaum [12] described a method of using return possible that such a low-latency system may be developed addresses in mix-nets: recipients encode a reply path, and which is both secure against end-to-end analysis and cost- allow senders to affix messages to the encoded path. As the effective to operate, but no such system has yet been proven message moves through the network, the path is decoded feasible. and the message encoded at each hop, until an encoded mes- sage reaches its eventual recipient. This system relies upon 2.1.4 Network-level server anonymity. all selected component nodes of the chosen path remaining The second generation implementation of Onion Routing, operational in order for mail to be delivered, which can make Tor [28], implements rendezvous points [31] that allow users the system too unreliable for practical use if significant time to offer location-hidden services. A user wishing to anony- elapses between path generation and message origination.1 mously receive messages can use this to receive mail at a In addition to reliability issues, some implementations of hidden location: messages are delivered to the server over these “reply blocks” suffer from a pseudonym management the Onion Routing network, and successful delivery does not perspective. Cypherpunk nym servers based on the first gen- require the sender to know the IP address of the destination eration implementation of Chaum’s mix-nets (Type I remail- server. ers [29]), such as alpha.c2.net [3] and nym.alias.net [45], Rendezvous points offer an alternative method of lever- implement a central reply-block repository that allowed the aging network-level anonymity systems for anonymous mail pseudonym holders to receive messages delivered to a email receipt; however, they do not address the previously men- address. Unfortunately, Type I remailers allow multiple uses tioned concerns with these anonymity systems. of their reply blocks, which are vulnerable to replay and flooding attacks as discussed in [16, 44]. Type II (Mixmas- 2.1.5 Re-encryption mixes. ter) and Type III (Mixminion [22]) systems do not permit Re-encryption mixes [35] aim to improve the reliability multiple-use reply blocks, and prevent replay attacks [17]. of anonymous message systems. Recent work has shown that re-encryption mixes can be used to facilitate anony- 2.1.2 Single-use reply blocks. mous message replies [34]. While reusable anonymous re- While the Type II system does not support anonymous turn channels in re-encryption mixes do improve on the reply blocks, the Type III (Mixminion) system introduces robustness of simple reply blocks in a Chaumian mix-net, single-use reply blocks (SURBs) [39] to avoid replay attacks.
Load more

Recommended publications
  • Security Applications of Formal Language Theory
    Dartmouth College Dartmouth Digital Commons Computer Science Technical Reports Computer Science 11-25-2011 Security Applications of Formal Language Theory Len Sassaman Dartmouth College Meredith L. Patterson Dartmouth College Sergey Bratus Dartmouth College Michael E. Locasto Dartmouth College Anna Shubina Dartmouth College Follow this and additional works at: https://digitalcommons.dartmouth.edu/cs_tr Part of the Computer Sciences Commons Dartmouth Digital Commons Citation Sassaman, Len; Patterson, Meredith L.; Bratus, Sergey; Locasto, Michael E.; and Shubina, Anna, "Security Applications of Formal Language Theory" (2011). Computer Science Technical Report TR2011-709. https://digitalcommons.dartmouth.edu/cs_tr/335 This Technical Report is brought to you for free and open access by the Computer Science at Dartmouth Digital Commons. It has been accepted for inclusion in Computer Science Technical Reports by an authorized administrator of Dartmouth Digital Commons. For more information, please contact [email protected]. Security Applications of Formal Language Theory Dartmouth Computer Science Technical Report TR2011-709 Len Sassaman, Meredith L. Patterson, Sergey Bratus, Michael E. Locasto, Anna Shubina November 25, 2011 Abstract We present an approach to improving the security of complex, composed systems based on formal language theory, and show how this approach leads to advances in input validation, security modeling, attack surface reduction, and ultimately, software design and programming methodology. We cite examples based on real-world security flaws in common protocols representing different classes of protocol complexity. We also introduce a formalization of an exploit development technique, the parse tree differential attack, made possible by our conception of the role of formal grammars in security. These insights make possible future advances in software auditing techniques applicable to static and dynamic binary analysis, fuzzing, and general reverse-engineering and exploit development.
    [Show full text]
  • 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.
    [Show full text]
  • Studying the Anonymity Trilemma with a Discrete-Event Mix Network Simulator Ania M
    Studying the anonymity trilemma with a discrete-event mix network simulator Ania M. Piotrowska Nym Technologies ABSTRACT strategies on the example of Elixxir [2], HOPR [4] and Nym [1]. To In this work, we present a discrete event mix network simulator, the best of our knowledge, this is a first such empirical analysis of which allows analysing how anonymity, latency, and bandwidth those networking designs. overhead are affected by various scenarios of deployment and de- sign choices. These design choices include network topology, mix- 2 BACKGROUND ing technique, volume of traffic, latency requirements, packet size or use of cover traffic. To the best of our knowledge, this isthe The concept of an anonymous communication network was pio- first such simulator as work on it began in 2017 to analyze the neered by Chaum [7] to mitigate the threats of progressive com- Loopix mix network, and the code of our simulator is available munications surveillance. Their main security goal is to shield the under an open-source license. To demonstrate the capabilities of correspondence between senders and recipients by hiding the dis- our simulator, we perform an empirical analysis of the impact of tinctive characteristics of the network traffic, the so called metadata. core design choices on anonymity, scalability and latency in Elixxir, The principal concept of the Chaum’s anonymous communication HOPR and Nym, currently deployed mix network infrastructures network is the decentralized mix network in which the network that make a variety of different choices in their design. traffic is relayed via a set of independently operated cryptographic relays called mix nodes.
    [Show full text]
  • Privacy and Data Protection by Design – from Policy to Engineering December 2014
    Privacy and Data Protection by Design – from policy to engineering December 2014 European Union Agency for Network and Information Security www.enisa.europa.eu Privacy and Data Protection by Design – from policy to engineering December 2014 About ENISA The European Union Agency for Network and Information Security (ENISA) is a centre of network and information security expertise for the EU, its member states, the private sector and Europe’s citizens. ENISA works with these groups to develop advice and recommendations on good practice in infor- mation security. It assists EU member states in implementing relevant EU legislation and works to improve the resilience of Europe’s critical information infrastructure and networks. ENISA seeks to enhance existing expertise in EU member states by supporting the development of cross-border com- munities committed to improving network and information security throughout the EU. More infor- mation about ENISA and its work can be found at www.enisa.europa.eu. Authors George Danezis, Josep Domingo-Ferrer, Marit Hansen, Jaap-Henk Hoepman, Daniel Le Métayer, Rodica Tirtea, Stefan Schiffner Contact For contacting the authors please use [email protected] For media enquires about this paper, please use [email protected]. Acknowledgements We have discussed this work with numerous people at various occasions; we thank for the valuable input we got from these discussions. While we cannot name all, we would like to thank Sébastien Gambs and Rosa Barcelo for their feedback on drafts of this report. Legal notice Notice must be taken that this publication represents the views and interpretations of the authors and edi- tors, unless stated otherwise.
    [Show full text]
  • 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.
    [Show full text]
  • 2013-07-08-Security Researchers Amicus.Pdf
    Case: 13-1816 Document: 003111316712 Page: 1 Date Filed: 07/08/2013 No. 13-1816 In the United States Court of Appeals for the Third Circuit United States of America, Plaintiff-Appellee, v. Andrew Auernheimer, Defendant-Appellant. Appeals from the United States District Court for the District of New Jersey, Case No. 11-CR-470, Judge Susan D. Wigenton Brief of Meredith Patterson, Brendan O’Connor, Sergey Bratus, Gabriella Coleman, Peyton Engel, Matthew Green, Dan Hirsch, Dan Kaminsky, Samuel Liles, Shane MacDougall, Brian Martin, C. Thomas, and Peiter Zatko as Amici Curiae Supporting Appellant Alex Muentz Adjunct Instructor Department of Criminal Justice Gladfelter Hall, 5th floor Temple University 1115 Polett Walk Philadelphia PA 19122 (215) 806-4383 Case: 13-1816 Document: 003111316712 Page: 2 Date Filed: 07/08/2013 Table of Contents Interest of Amici Curiae .......................1 Non-Party Statement .........................2 Consent to File ............................2 Summary of Argument.........................2 Argument................................3 1 Allowing a corporation to serve data publicly, then state after the fact that access was secretly restricted and thus impose criminal liability, amounts to a private criminal law, and may also violate the Ex Post Facto Clause. ...............................3 2 Criminalizing access to publicly-offered material is not in the public in- terest, because it prevents the security research community from exer- cising its consumer-protecting role. .................. 16 Conclusion............................... 21 Certificate of Bar Membership.................... 23 Certificate of Compliance With Word Count Requirements ... 23 Certificate of Service ........................ 23 Certificate of Identical Compliance of Briefs ........... 24 Certificate of Virus Check ...................... 24 ii Case: 13-1816 Document: 003111316712 Page: 3 Date Filed: 07/08/2013 Table of Authorities Cases Calder v.
    [Show full text]
  • Toward an Information Theoretic Secure Anonymous Communication Service the Pynchon Gate Pseudonymous Mail System
    Toward an Information Theoretic Secure Anonymous Communication Service The Pynchon Gate Pseudonymous Mail System Len Sassaman1, Nick Mathewson2, Brian Warner3, Bram Cohen4, and Bart Preneel1 1 Katholieke Universiteit Leuven Kasteelpark Arenberg 10, B-3001 Leuven-Heverlee, Belgium flen.sassaman,[email protected] 2 The Free Haven Project [email protected] 3 Allmydata, Inc. 555 De Haro Street, Suite 400, San Francisco CA, 94107 USA [email protected] 4 BitTorrent, Inc. 201 Mission Street, Suite 900, San Francisco, CA 94105 [email protected] Abstract. We describe the Pynchon Gate, a practical pseudonymous message retrieval system. Our design uses a simple distributed-trust pri- vate information retrieval protocol to prevent adversaries from linking recipients to their pseudonyms, even when some of the infrastructure has been compromised. This approach resists global traffic analysis sig- nificantly better than existing deployed pseudonymous email solutions, at the cost of additional bandwidth. This design improves upon previous versions by being resistant to Byzantine servers. We provide a review of related work, and evaluate it in comparison to our approach. We exam- ine security concerns raised by our model,and propose solutions. Special emphasis is placed on ease of implementation and deployment of the system, as well as end-user usability issues. 1 Introduction Over the last several decades, there have been numerous systems proposed which aim to preserve the anonymity of the recipient of some data. Some have involved trusted third-parties or trusted hardware; others have been constructed on top of link-layer anonymity systems or mix networks. Pseudonymous messaging services allow users to send messages that originate at a pseudonymous address (or \nym") unlinked to the user, and to receive mes- sages sent to that address, without allowing an attacker to deduce which users are associated with which pseudonyms.
    [Show full text]
  • Financial Technology
    Journal APEX 2016 AWARD WINNER FINANCIAL TECHNOLOGY Available to download at CAPCO.COM/INSTITUTE #44 11.2016 EMPOWERING THE [FINANCIAL] WORLD Pushing the pace of Financial Technology, together we’ll help our clients solve technology challenges for their business – whether it’s capital markets in Mumbai or community banking in Macon. We leverage knowledge and insights from our clients around the world: clients in towns everywhere are becoming 20,000 more efficient, modern and scalable. transactions processed help solve clients’ 27 billion challenges — big and small. moved across the globe in a single year $9 trillion empowers our clients’ communities to build storefronts, homes and careers. hearts and minds have joined forces to 55,000 bring you greater capabilities in even the smallest places. Empowering the Financial World FISGLOBAL.COM © 2016 FIS and/or its subsidiaries. All Rights Reserved. The Capco Institute Journal of Financial Transformation Recipient of the Apex Award for Publication Excellence Editor Shahin Shojai, Global Head, Capco Institute Advisory Board Christine Ciriani, Partner, Capco Chris Geldard, Partner, Capco Nick Jackson, Partner, Capco Editorial Board Franklin Allen, Nippon Life Professor of Finance, University of Pennsylvania Joe Anastasio, Partner, Capco Philippe d’Arvisenet, Adviser and former Group Chief Economist, BNP Paribas Rudi Bogni, former Chief Executive Officer, UBS Private Banking Bruno Bonati, Chairman of the Non-Executive Board, Zuger Kantonalbank Dan Breznitz, Munk Chair of Innovation Studies, University of Toronto Urs Birchler, Professor Emeritus of Banking, University of Zurich Géry Daeninck, former CEO, Robeco Stephen C. Daffron, CEO, Interactive Data Jean Dermine, Professor of Banking and Finance, INSEAD Douglas W.
    [Show full text]
  • 09.Conference Reports Copy
    conference reports This issue’s report focusses on LISA LISA XVI only, so single failures aren’t fatal but only reduce capacity. XVI Sixteenth Systems Administration Conference To answer a query, the Web server (a custom package called gws) queries PHILADELPHIA, PENNSYLVANIA, index servers, document servers (cached USA pages), and ad servers, in parallel, and OUR THANKS TO THE SUMMARIZERS: NOVEMBER 3–8, 2002 keeps trying until it gets a response. KEYNOTE Each query may involve a dozen or more servers, using whichever reply comes in for LISA ’02 SCALING THE WEB: AN OVERVIEW OF the fastest (the average query time is .23 Josh Simon, who organized the collecting of GOOGLE (A LINUX CLUSTER FOR FUN seconds). Before the query reaches a the summaries AND PROFIT) Abiodun A. Alao Web server, however, it passes several Jim Reese, Chief Operations Engineer, Paul Anderson Google load balancers, both global and local, David Berg which use various methods (including Robert Beverly Summarized by J.D. Welch round-robin and least connections) to Kuzman Ganchev We all know, use, and love Google, but Jim Hickstein choose which servers to query. Rob Kolstad how do they make it work? In this Martin Krafft engaging talk, Jim Reese explained how “El Cheapo” PCs are used to maximize Renuka Nayak custom software, massive replication reliability through replication. Fault tol- James O’Kane and expendable, commodity hardware erance is kept very simple; timeouts are Will Partain have allowed Google to answer 150 mil- in the milliseconds, and machines are Peg Schafer restarted automatically and regularly J. D. Welch lion Web search queries a day.
    [Show full text]
  • Winter 2020 Vol
    ;login WINTER 2020 VOL. 45, NO. 4 : & Characterizations of Cloud Functions Workloads Mohammad Shahrad, Rodrigo Fonseca, Íñigo Goiri, Gohar Chaudhry, and Ricardo Bianchini & RLBox: Simplifying In-Process Sandboxing Tal Garfinkel, Shravan Narayan, Craig Disselkoen, Hovav Shacham, and Deian Stefan & BIBIFI Contests: Motivated Developers Still Make Security Mistakes Daniel Votipka, Kelsey R. Fulton, James Parker, Matthew Hou, Michelle L. Mazurek, and Michael Hicks & SRE Best Practices for Capacity Final Print Issue Specials Management Favorite Articles Luis Quesada Torres and Doug Colish Rik Farrow, Laura Nolan, and Arvind Krishnamurthy Interview with USENIX Member #7 Rik Farrow Interview with Kirk McKusick Columns Rik Farrow Review of Alex Hidalgo’s Book about SLOs Open Access Laura Nolan Laura Nolan Understanding Linux Containers Corey Lueninghoener BPF and Histograms Dave Josephsen Cryptographic Hash Functions Simson L. Garfinkel Software Supply Chain Security Dan Geer, Bentz Tozer, and John Speed Meyers Thanks to our USENIX Supporters! USENIX appreciates the financial assistance our Supporters provide to subsidize our day-to-day operations and to continue our non-profit mission. Our supporters help ensure: • Free and open access to technical information • Student Grants and Diversity Grants to participate in USENIX conferences • The nexus between academic research and industry practice • Diversity and representation in the technical workplace We need you now more than ever! Contact us at [email protected]. USENIX PATRONS USENIX BENEFACTORS USENIX PARTNERS We offer our heartfelt appreciation to the following sponsors and champions of conference diversity, open access, and our SREcon communities via their sponsorship of multiple conferences: Ethyca Equinix Metal Microsoft Azure Goldman Sachs LinkedIn Salesforce More information at www.usenix.org/supporters WINTER 2020 VOL.
    [Show full text]
  • Bitcoin Is Speech: Notes Towards Developing Conceptual Contours Of
    University of Miami Law Review Volume 74 Number 1 Article 6 11-22-2019 Bitcoin is Speech: Notes Toward Developing the Conceptual Contours of Its Protection Under the First Amendment Justin S. Wales Richard J. Ovelmen Follow this and additional works at: https://repository.law.miami.edu/umlr Part of the First Amendment Commons, Law and Economics Commons, and the Law and Society Commons Recommended Citation Justin S. Wales and Richard J. Ovelmen, Bitcoin is Speech: Notes Toward Developing the Conceptual Contours of Its Protection Under the First Amendment, 74 U. Miami L. Rev. 204 (2019) Available at: https://repository.law.miami.edu/umlr/vol74/iss1/6 This Article is brought to you for free and open access by the Journals at University of Miami School of Law Institutional Repository. It has been accepted for inclusion in University of Miami Law Review by an authorized editor of University of Miami School of Law Institutional Repository. For more information, please contact [email protected]. Bitcoin is Speech: Notes Toward Developing the Conceptual Contours of Its Protection Under the First Amendment JUSTIN S. WALES & RICHARD J. OVELMEN* Bitcoin permits users to engage in direct expressive act- ivity with one another without the need for centralized inter- mediaries. It does so by utilizing an open and community- managed global database called a blockchain. While much of the literature about Bitcoin has focused on its use as a form of digital payment, this Article suggests an expanded understanding by demonstrating its use as a protocol net- work, not unlike the internet, that can be used to extend the possible range of human expression.
    [Show full text]
  • Better Anonymous Communications
    Better Anonymous Communications George Danezis University of Cambridge Computer Laboratory Queens' College January 2004 This dissertation is submitted for the degree of Doctor of Philosophy Declaration This dissertation is the result of my own work and includes nothing which is the outcome of work done in collaboration except where speci¯cally indi- cated in the text and summarised in section 1.3. This dissertation does not exceed the regulation length of 600001 words, including tables and footnotes. 1using detex thesis.tex | wc Acknowledgements \No man is an island, entire of itself; every man is a piece of the continent, a part of the main." Meditation 17, Devotions Upon Emergent Occasions | John Donne I am deeply indebted to my supervisor and teacher Ross Anderson, for al- lowing me to join his research group, and helping me at key points during the last three years. I hope this document shows that his trust in me was justi¯ed. I am also grateful to Robin Walker, my director of studies, for his support during the last six years and for giving me the opportunity to study in Cambridge. These years of research would have been considerably less productive without the local scienti¯c community, my colleagues in the computer secu- rity group of the Computer Laboratory, but also my colleagues from around the world. I would like to specially thank my co-authors, Richard Clayton, Markus Kuhn, Andrei Serjantov, Roger Dingledine, Nick Mathewson and Len Sassaman. This research would not have been possible without my parents. At every stage of my academic life they acted as role models, provided moral and ¯nancial support.
    [Show full text]