Anonymous Network Concepts & Implementation
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IPFS and Friends: a Qualitative Comparison of Next Generation Peer-To-Peer Data Networks Erik Daniel and Florian Tschorsch
1 IPFS and Friends: A Qualitative Comparison of Next Generation Peer-to-Peer Data Networks Erik Daniel and Florian Tschorsch Abstract—Decentralized, distributed storage offers a way to types of files [1]. Napster and Gnutella marked the beginning reduce the impact of data silos as often fostered by centralized and were followed by many other P2P networks focusing on cloud storage. While the intentions of this trend are not new, the specialized application areas or novel network structures. For topic gained traction due to technological advancements, most notably blockchain networks. As a consequence, we observe that example, Freenet [2] realizes anonymous storage and retrieval. a new generation of peer-to-peer data networks emerges. In this Chord [3], CAN [4], and Pastry [5] provide protocols to survey paper, we therefore provide a technical overview of the maintain a structured overlay network topology. In particular, next generation data networks. We use select data networks to BitTorrent [6] received a lot of attention from both users and introduce general concepts and to emphasize new developments. the research community. BitTorrent introduced an incentive Specifically, we provide a deeper outline of the Interplanetary File System and a general overview of Swarm, the Hypercore Pro- mechanism to achieve Pareto efficiency, trying to improve tocol, SAFE, Storj, and Arweave. We identify common building network utilization achieving a higher level of robustness. We blocks and provide a qualitative comparison. From the overview, consider networks such as Napster, Gnutella, Freenet, BitTor- we derive future challenges and research goals concerning data rent, and many more as first generation P2P data networks, networks. -
A Transport Layer Abstraction for Peer-To-Peer Networks Ronaldo A
A Transport Layer Abstraction for Peer-to-Peer Networks Ronaldo A. Ferreira, Christian Grothoff and Paul Ruth Department of Computer Sciences Purdue University g frf,grothoff,ruth @cs.purdue.edu http://www.gnu.org/software/GNUnet/ B Abstract— The initially unrestricted host-to-host communica- same peer-to-peer network. In fact, two peers A and may tion model provided by the Internet Protocol has deteriorated want to use differentmodes of communicationon the same link. due to political and technical changes caused by Internet growth. For example, suppose node B is behind a NAT box and cannot While this is not a problem for most client-server applications, peer-to-peer networks frequently struggle with peers that are be reached directly via UDP or TCP. In a system with multiple only partially reachable. We describe how a peer-to-peer frame- transport protocols, A could initiate a connection by sending an B A work can hide diversity and obstacles in the underlying Internet e-mail to B (SMTP) and then have contact via TCP, al- and provide peer-to-peer applications with abstractions that hide lowing A to continue further communication on a bidirectional transport specific details. We present the details of an implemen- TCP connection. tation of a transport service based on SMTP. Small-scale bench- marks are used to compare transport services over UDP, TCP, and We will use GNUnet as our reference peer-to-peer system, SMTP. but it should be clear that the idea of a transport abstraction can be applied to other systems. GNUnet is a peer-to-peer frame- work whose main focus is on security [1], [5]. -
Recognition and Investigation of Listening in Anonymous Communication Systems 1 K
AEGAEUM JOURNAL ISSN NO: 0776-3808 Recognition and investigation of listening in anonymous communication systems 1 K. Balasubramanian, 2 Dr. S. Kannan, 3 S. Sharmila 1Associate Professor, Department of CSE, E.G.S Pillay Engineering College, Nagapattinam, Tamil Nadu, India. Email: [email protected] 2, Professor, Department of CSE, E.G.S Pillay Engineering College, Nagapattinam, Tamil Nadu, India. 3, P.G Student, Department of CSE, E.G.S Pillay Engineering College, Nagapattinam, Tamil Nadu, India. Abstract components through which client activity is steered can Mysterious correspondence systems similar to listen in and get delicate information, for example, user Tor, mostly secure the secrecy of client activity by verification qualifications. This circumstance can scrambling all interchanges inside the overlay system. conceivably decline when clients utilize intermediary based frameworks to get to similar administrations However, when the transferred activity achieves the without utilizing end-to-end encryption, as the quantity limits of the system, toward its end, the first client of hosts or hubs that can listen stealthily on their activity is definitely presented to the last node on the movement increments. Different open and private path. Accordingly, users sending sensitive information, systems may square access to interpersonal interaction similar to verification accreditations, over such and other prominent online administrations for systems, risk having their information between different reasons. Under these conditions, users accepted and uncovered, unless end-to-end encryption regularly depend on utilizing disseminated proxying frameworks to prevent their activity from being is utilized. Listening can be performed by malicious or filtered. They fall back on such mechanisms so as to compromised relay nodes, and additionally any rebel evade system activity filtering in light of source, goal, arrange substance on the way toward the actual end. -
Tools for Breaking out of PRISM
Tools for Breaking out of PRISM Christian Grothoff The GNUnet Project \Never doubt your ability to change the world." {Glenn Greenwald Everybody Has Secrets I Business & Trade Secrets I Political opinions I Illegal activities Send everything to US in plaintext Keeping Secrets I Encryption: baseline I Hide meta-data: state of the art I Practice today? Keeping Secrets I Encryption: baseline I Hide meta-data: state of the art I Practice today? Send everything to US in plaintext I PRISM enables real-time surveillance and access to stored content I Data collected: E-mails, instant messages, videos, photos, stored data (likely files), voice chats, file transfers, video conferences, log-in times, and social network profiles I Tiny part of NSA: $20 M budget I Guardian: \The PRISM program allows the intelligence services direct access to the companies servers." I Cooperating providers: Microsoft, Yahoo, Google, Facebook, PalTalk, YouTube, Skype, AOL, Apple I Guardian: \The PRISM program allows the intelligence services direct access to the companies servers." I Cooperating providers: Microsoft, Yahoo, Google, Facebook, PalTalk, YouTube, Skype, AOL, Apple I PRISM enables real-time surveillance and access to stored content I Data collected: E-mails, instant messages, videos, photos, stored data (likely files), voice chats, file transfers, video conferences, log-in times, and social network profiles I Tiny part of NSA: $20 M budget US discussion focuses on spying on US citizens and legality under US law. Frank Church (D-Idaho): \The NSA's capability at any -
Censorship-Resistant Collaboration with a Hybrid DTN/P2P Network
Censorship-resistant Collaboration with a Hybrid DTN/P2P Network Masterarbeit von Philipp Hagemeister aus Braunschweig vorgelegt am Lehrstuhl fur¨ Rechnernetze und Kommunikationssysteme Prof. Dr. Martin Mauve Heinrich-Heine-Universitat¨ Dusseldorf¨ Marz¨ 2012 Acknowledgments My thanks go to Marc Fontaine for asking stupid questions that turned out to be quite clever, and for pointing out that correctness is essential both in the real and the physical world. I also thank Paul Baade for demanding impossible features which turned out to be the last piece in the puzzle. Julius Rommler¨ has notified me of orthographical, typographical, and (inadvertently) semantical er- rors. And told me to use fewer big words. Thanks! I wish to thank Denis Lutke-Wiesmann¨ for proofreading the thesis, and the footnotes. Sven Hager found lots of overly short, overly long, and overly wrong statements. Thanks! Thanks to Prof. Martin Mauve for coming up with the idea, shielding us from bureaucracy, asking for explanation and rationale at every step, and finding all the errors nobody else found. iii Contents List of Figures viii 1 Motivation 1 1.1 Distribution of Speech . .2 1.2 Threat Model . .2 1.2.1 Nontechnical Attacks . .2 1.2.2 Internet Access . .3 1.2.3 Control over the User’s Computer . .4 1.2.4 Total Shutoff . .4 1.2.5 Physical Attacks . .5 1.2.6 IP Blocking . .5 1.2.7 DNS censorship . .6 1.2.8 Deep Packet Inspection . .6 1.2.9 Active Attacks . .8 1.2.10 Conclusions . .9 1.3 Decentralization . 10 1.4 Collaboration . 10 1.5 Structure of this Thesis . -
Copyright Assignment Agreement for Contributors to GNU Taler
Copyright Assignment Agreement for Contributors to GNU Taler Between: GNUnet e.V., a German association of GNUnet developers registered in München and seated in Garching bei München, represented by an authorized currently elected representative of the GNUnet e.V. Vorstand, hereinafter refer- red to as GNUnet e.V., And: hereinafter referred to as the Contributor. IT HAVING BEEN PREVIOUSLY ESTABLISHED: • That the GNU Taler project is directed and supported by GNUnet e.V., which aims to develop the GNU Taler software as part of the GNU project, distributed under GNU licenses (GNU Aero GPL, GNU GPL v3+, GNU LGPL) on the date of signing of this contract; • That this development project is opened to contributions submitted by individuals outside of GNUnet e.V., contributions which may be ocially submitted by their holder to GNUnet e.V. for the purpose of being integrated by the latter into the GNU Taler software, in successive versions edited and distributed by GNUnet e.V. or the GNU project; • That GNUnet e.V. wishes, in this context, to centralize copyright ownership on any new contribution integrated into the GNU Taler software edited and distributed by it; • That the Contributor wishes to participate, or authorize its personnel to participate, in the development of the aforementioned software; • That GNUnet e.V. has a publicly available licensing and collaborative development agree- ment with Taler Systems S.A. enabling Taler Systems S.A. to productize GNU Taler as a free software project subject to licensing constraints compatible with those imposed on GNUnet e.V. and granted to GNUnet e.V. -
El Gamal Mix-Nets and Implementation of a Verifier
KTH Royal Institute of Technology School of Computer Science and Communication El Gamal Mix-Nets and Implementation of a Verifier SA104X Degree Project in Engineering Physics Erik Larsson ([email protected]) Carl Svensson ([email protected]) Supervisor: Douglas Wikstr¨om Abstract A mix-net is a cryptographic protocol based on public key cryptography which enables untraceable communication through a collection of nodes. One important application is electronic voting where it enables the construction of systems which satisfies many voting security requirements, including veri- fiability of correct execution. Verificatum is an implementation of a mix-net by Douglas Wikstr¨om. This report concerns the implementation of a verifier and evaluation of the implementation manual for the Verificatum mix-net. The purpose of the document is to enable third parties to convince themselves that the mix- net has behaved correctly without revealing any secret information. This implementation is a simple version of the verifier using the document and some test vectors generated by the mix-net. The document contains all information but there are still some possibilities for further clarification in order to make it comprehensible to a larger audience. Contents 1 Introduction 2 1.1 Verificatum . 2 1.2 Goals and Scope . 3 2 Background 3 2.1 El Gamal Cryptography . 3 2.1.1 Definition . 4 2.1.2 Security . 4 2.1.3 Properties . 5 2.2 Cryptographic Primitives . 6 2.2.1 Hash functions . 6 2.2.2 Pseudo Random Generators . 6 2.2.3 Random Oracles . 7 2.3 Mix Networks . 7 2.3.1 Overview . 7 2.3.2 El Gamal Mix-Nets . -
Multiparty Routing: Secure Routing for Mixnets
Multiparty Routing: Secure Routing for Mixnets Fatemeh Shirazi Elena Andreeva Markulf Kohlweiss Claudia Diaz imec - COSIC KU Leuven imec - COSIC KU Leuven Microsoft Research imec - COSIC KU Leuven Leuven, Belgium Leuven, Belgium Cambridge, UK Leuven, Belgium Abstract—Anonymous communication networks are impor- re-mailer, Freenet [5], [6] used for anonymous file-sharing, and tant building blocks for online privacy protection. One approach DC-Nets [7] that can be deployed for broadcast applications to achieve anonymity is to relay messages through multiple such as group messaging. routers, where each router shuffles messages independently. To achieve anonymity, at least one router needs to be honest. The goal of ACNs is to anonymize communications by In the presence of an adversary that is controlling a subset relaying them over multiple routers. There are three main types of the routers unbiased routing is important for guaranteeing of anonymous routing in terms of how routers are chosen to anonymity. However, the routing strategy also influenced other form the path. factors such as the scalability and the performance of the system. One solution is to use a fixed route for relaying all messages First, in deterministic routing, the paths are predetermined with many routers. If the route is not fixed the routing decision by the system configuration. Chaum’s original ACN pro- can either be made by the communication initiator or the posal [1] considered a sequence of mixes organized in a intermediate routers. However, the existing routing types each cascade. Systems that adopted the cascade network topology have limitations. For example, one faces scalability issues when in their designs include JAP [8], and voting systems, such as increasing the throughput of systems with fixed routes. -
Walking Onions: Scaling Anonymity Networks While Protecting Users Chelsea H
Walking Onions: Scaling Anonymity Networks while Protecting Users Chelsea H. Komlo, University of Waterloo; Nick Mathewson, The Tor Project; Ian Goldberg, University of Waterloo https://www.usenix.org/conference/usenixsecurity20/presentation/komlo This paper is included in the Proceedings of the 29th USENIX Security Symposium. August 12–14, 2020 978-1-939133-17-5 Open access to the Proceedings of the 29th USENIX Security Symposium is sponsored by USENIX. Walking Onions: Scaling Anonymity Networks while Protecting Users Chelsea H. Komlo Nick Mathewson Ian Goldberg University of Waterloo The Tor Project University of Waterloo Abstract Anonymity networks in practice [13] have prevented these Scaling anonymity networks offers unique security chal- attacks by requiring all participants to share a globally consis- lenges, as attackers can exploit differing views of the net- tent view of the entire state of the network, and giving clients work’s topology to perform epistemic and route capture at- complete control over selecting relays for their paths. While tacks. Anonymity networks in practice, such as Tor, have this approach prevents the described attacks, requiring a glob- opted for security over scalability by requiring participants ally consistent view results in quadratic bandwidth growth as to share a globally consistent view of all relays to prevent the number of clients increases [26], because the number of these kinds of attacks. Such an approach requires each user relays must also increase to provide more capacity, and all to maintain up-to-date information about every relay, causing parties must download information about all relays. While the total amount of data each user must download every epoch today’s Tor network requires only approximately half a per- to scale linearly with the number of relays. -
Let's Make a GNU One! P≡P Privacy by Default
Speaker GNUnet.org IRC:sva [email protected] twitter@sva Let's make a GNU one! p≡p Privacy by Default. GNUnet 1970/80: Internet v1.0. Wow, I can access your computer, you can check out mine! Awesome! 2010/20: Internet v1.1. Sure I can access other computers and use their services. Wait, What? hey can also access mine!? 2025/30: Internet v2.0. "nd-to#end encryption and anonymi$ation of the ways data flows. p≡p Privacy by Default. Whats the problem of v1.1.? Network knows & learns too much Insecure de%au!ts & high comp!exities )entrali$ed components *e.g. IANA, ICANN, DNS, …) Administrators can be a target! /isuse of those flaws happens a!! over! p≡p Privacy by Default. Idea 0GNUnet is a mesh routing layer %or end#to#end encrypted networking and a %ramework %or distri.uted applications designed to replace the old insecure Internet protocol stack.1 GNUnet.org *%ounded 2332, %ollowed in academia) p≡p Privacy by Default. Layers *very hard- simplified version of the Internet: Google, FB ' Co +NS9:.;3< )=9U+= I=9BG= "thernet Physical Layer p≡p Privacy by Default. Layers Internet: GNUnet6 Google, FB & Co ... +NS/X.;3< ... )=9U+= ... I=/BGP ... "thernet ... =hysical Layer ... p≡p Privacy by Default. Layers Internet: GNUnet6 Google, FB & Co ... +NS/X.;3< ... )=9U+= ... I=/BGP ... "thernet ... =hysical Layer > =S/TCP9WLAN/... p≡p Privacy by Default. Layers GNUnet6 Start with what we have: ... e.g. )=, U+=, S/ =, H =, H =S, WLAN, Bluetooth, ,. ... Unreliable, out-o%-order packet ... delivery semantics. ... Automated ransport Selection *ATS- decides. -
Network Security
Cristina Nita-Rotaru CS6740: Network security Anonymity. Sources 1. Crowds: http://avirubin.com/crowds.pdf 2. Chaum mix: http://www.ovmj.org/GNUnet/papers/p84-chaum.pdf 3. To r : https://svn.torproject.org/svn/projects/design-paper/tor-design.pdf 4. Predecessors attack: http://prisms.cs.umass.edu/brian/pubs/wright-tissec.pdf 5. Also based on slides prepared by Chi-Cun Chan. 2 Anonymity systems. 1: Motivation Anonymity Anonymity (``without name’’) means that a person is not identifiable within a set of subjects } Unlinkability of action and identity } For example, sender and his email are no more related after adversary’s observations than they were before } Who talks to whom } Unobservability } Adversary cannot tell whether someone is using a particular system and/or protocol 4 Anonymity systems. There is no anonymity on the Internet } Your IP address can be linked directly to you } ISPs store communications records } Usually for several years (Data Retention Laws) } Law enforcement can subpoena these records } Your browser is being tracked } Cookies, Flash cookies, E-Tags, HTML5 Storage } Browser fingerprinting } Your activities can be used to identify you } Unique websites and apps that you use } Types of links that you click 5 Anonymity systems. Wiretapping is ubiquitous } Wireless traffic can be trivially intercepted } Airsnort, Firesheep, etc. } Wifi and Cellular traffic! } Encryption helps, if it’s strong } WEP and WPA are both vulnerable! } Tier 1 ASs and IXPs are compromised } NSA, GCHQ, “5 Eyes” } ~1% of all Internet traffic } Focus on encrypted traffic 6 Anonymity systems. Who uses anonymity systems? } “If you’re not doing anything wrong, you shouldn’t have anything to hide.” } Implies that anonymous communication is for criminals } The truth: who uses Tor? } Journalists } Law enforcement ¤ Business executives } Human rights activists ¤ Military/intelligence personnel } Normal people ¤ Abuse victims } In fact, the predecesor of Tor was developed by the U.S. -
A System for Privacy-Preserving Mobile Health and Fitness Data Sharing: Design, Implemen- Tation and Evaluation Master Thesis SEEMOO-MSC-0076
A SYSTEM FOR PRIVACY-PRESERVING MOBILE HEALTH AND FITNESSDATASHARING:DESIGN,IMPLEMENTATIONAND E VA L U AT I O N max jakob maaß Master Thesis April 15, 2016 Secure Mobile Networking Lab Department of Computer Science A System for Privacy-Preserving Mobile Health and Fitness Data Sharing: Design, Implemen- tation and Evaluation Master Thesis SEEMOO-MSC-0076 Submitted by Max Jakob Maaß Date of submission: April 15, 2016 Advisor: Prof. Dr.-Ing. Matthias Hollick Supervisor: Prof. Dr.-Ing. Matthias Hollick Technische Universität Darmstadt Department of Computer Science Secure Mobile Networking Lab ABSTRACT The growing spread of smartphones and other mobile devices has given rise to a number of health and fitness applications. Users can track their calorie intake, get reminders to take their medication, and track their fitness workouts. Many of these services have social com- ponents, allowing users to find like-minded peers, compete with their friends, or participate in open challenges. However, the prevalent ser- vice model forces users to disclose all of their data to the service provider. This may include sensitive information, like their current position or medical conditions. In this thesis, we will design, imple- ment and evaluate a privacy-preserving fitness data sharing system. The system provides privacy not only towards other users, but also against the service provider, does not require any Trusted Third Par- ties (TTPs), and is backed by strong cryptography. Additionally, it hides the communication metadata (i.e. who is sharing data with whom). We evaluate the security of the system with empirical and formal methods, including formal proofs for parts of the system.