An Innovative Approach Towards Applying Chaum Mixing to SMS

Currently there are few user-friendly applications for anonymous communication across multiple platforms, leaving data that is often both personal and private vulnerable to malicious activity. Mobile devices such as smartphones are prime candidates for such an application as they are pervasive and have standardized communication protocols. Through the application of mixing techniques, these devices can provide anonymity for groups of individuals numbering 30 to 40 members. In this work, a Chaum mix inspired, smartphone based network that uses the Short Message Service (SMS) is described first in theory and then in implementation. This system leverages both techniques used by current anonymity networks as well as knowledge gained from current and past research to make messages private and untraceable. The work addresses previously published attacks to anonymous systems through current and innovative mitigation technique

Mitigating Distributed Denial of Service Attacks in an Anonymous Routing Environment: Client Puzzles and Tor

Online intelligence operations use the Internet to gather information on the activities of U.S. adversaries. The security of these operations is paramount, and one way to avoid being linked to the Department of Defense (DoD) is to use anonymous communication systems. One such system, Tor, makes interactive TCP services anonymous. Tor uses the Transport Layer Security (TLS) protocol and is thus vulnerable to a distributed denial-of-service (DDoS) attack that can significantly delay data traversing the Tor network. This research uses client puzzles to mitigate TLS DDoS attacks. A novel puzzle protocol, the Memoryless Puzzle Protocol (MPP), is conceived, implemented, and analyzed for anonymity and DDoS vulnerabilities. Consequently, four new secondary DDoS and anonymity attacks are identified and defenses are proposed. Furthermore, analysis of the MPP identified and resolved two important shortcomings of the generalized client puzzle technique. Attacks that normally induce victim CPU utilization rates of 80-100% are reduced to below 70%. Also, the puzzle implementation allows for user-data latency to be reduced by close to 50% during a large-scale attack .Finally, experimental results show successful mitigation can occur without sending a puzzle to every requesting client. By adjusting the maximum puzzle strength, CPU utilization can be capped at 70% even when an arbitrary client has only a 30% chance of receiving a puzzle

Improving security and efficiency of mix-based anonymous communication systems

The communication layer leaks important private information even in the presence of encryption, which makes anonymous communication a fundamental element of systems that protect the privacy of users. Traffic mixers have long been used to achieve communication anonymity, but the security challenges and the resulted inefficiencies hinder the path to a wide adoption of these systems. In this thesis, we take a step towards improving the security of traffic mixers and building a platform for efficient anonymous communication. We begin by revisiting Binomial Mix, which is one of the most effective designs for traffic mixing proposed to date, and the one that introduced randomness to the behaviour of traffic mixers. When thoroughly examined in different traffic conditions, Binomial Mix proved to be significantly more resilient against attacks than previously believed. We then build on the design of Binomial Mix and propose two new designs for traffic mixers. The first design, Multi-Binomial Shared-Pool Mix (MBSP Mix), employs multiple sources of randomness which results in a behaviour less predictable by the attacker and thus provides a higher degree of anonymity. The second design, Multi-Binomial Independent-Pool Mix (MBIP Mix), enables a single traffic mixer to anonymise multiple communication channels with potentially differing latencies. This additional property significantly improves the security and efficiency of the mix. Moving beyond the design of traffic mixers in isolation, we propose the architecture and details of a generic framework for anonymous communication. The proposed framework consists of various parts designed to enable the integration of various Anonymous Communication Systems as plug-in components into a shared and unified system. In addition to achieving a larger user-base and enjoying its associated security benefits, this approach enables the reusability of components across multiple communication systems. Finally, we also present techniques to make the circuit establishment facility of the framework resistant towards Denial-of-Service attacks. We believe that our work is one step towards building a fully developed generic framework for anonymous communication and our results can inspire and be used for the design of a robust generic framework

Prochlo: Strong Privacy for Analytics in the Crowd

The large-scale monitoring of computer users' software activities has become commonplace, e.g., for application telemetry, error reporting, or demographic profiling. This paper describes a principled systems architecture---Encode, Shuffle, Analyze (ESA)---for performing such monitoring with high utility while also protecting user privacy. The ESA design, and its Prochlo implementation, are informed by our practical experiences with an existing, large deployment of privacy-preserving software monitoring. (cont.; see the paper

An implementation of accountable anonymity

Complex well developed and established Anonymity systems lack Accountability. These systems offer unconditional anonymity to their users which can stimulate abusive behavior. Controlling abuse should be equally important as protecting the anonymity of legitimate users when designing anonymous applications. Current anonymity systems are promoted to family and friends, businesses, activists and the media. However, these same systems could potentially be used for: sending offensive email, spam, copyrighted material, cyber warfare, child pornography, pedophiles chatting with kids online or any other illegal activity performed on the Internet. Freedom of speech and the First Amendment allows people to express their opinions and choose any anonymity service and by no means will people be forced to use this system. In this thesis, a model that allows an anonymous yet accountable method of communication on the Internet is introduced. The design and implementation is based on a new proxy-re-encryption scheme and a modifed onion routing scheme. Techniques for Accountable Anonymity are demonstrated by building a lightweight prototype. In this system, users are registered in the system\u27s database in order to use it. In this research, the total network latency is signifcantly smaller when sending data over the network compared to The onion router (Tor) system which makes it deployable to use at a larger scale system. Also, the Accountable Anonymity system\u27s digital forensic mode makes it easier to track the perpetrators

Authoring the self: media, voice and testimony in soldiers memoirs

In this article, the author focuses on the struggles over self-representation that soldiers have engaged in at two key historical moments of modern Western warfare: the First World War, the first major industrialised conflict of the 20th century (1914–1918); and the Iraq and Afghanistan Wars, the so-called ‘War on Terror’, which marked the emergence of information warfare in the 21st century (2001–2014). The Western soldier’s self-representation, the author concludes, has shifted from a practice of observing the battlefield as a strange place and himself as an ‘other’ within it, to a practice of considering the ‘other’, here the Iraqi or Afghani local, as the self, someone who shares a Western sense of humanity. These antithetical self-representations, the author argues, point in turn to complex transformations in the technologies, moralities and cultures of warfare, throwing into relief uneasy tensions in the West’s 21st-century interventionist conflicts. In their attempt to move away from the massacres of the 20th-century wars, such conflicts are suspended between sharing humanity and misrecognising ‘others’, between liberating and conquering, between saving and taking lives

AOT: Anonymization by Oblivious Transfer

We introduce AOT, an anonymous communication system based on mix network architecture that uses oblivious transfer (OT) to deliver messages. Using OT to deliver messages helps AOT resist blending (n−1) attacks and helps AOT preserve receiver anonymity, even if a covert adversary controls all nodes in AOT. AOT comprises three levels of nodes, where nodes at each level perform a different function and can scale horizontally. The sender encrypts their payload and a tag, derived from a secret shared between the sender and receiver, with the public key of a Level-2 node and sends them to a Level-1 node. On a public bulletin board, Level-3 nodes publish tags associated with messages ready to be retrieved. Each receiver checks the bulletin board, identifies tags, and receives the associated messages using OT. A receiver can receive their messages even if the receiver is offline when messages are ready. Through what we call a handshake process, communicants can use the AOT protocol to establish shared secrets anonymously. Users play an active role in contributing to the unlinkability of messages: periodically, users initiate requests to AOT to receive dummy messages, such that an adversary cannot distinguish real and dummy requests

Low-latency mix networks for anonymous communication

Every modern online application relies on the network layer to transfer information, which exposes the metadata associated with digital communication. These distinctive characteristics encapsulate equally meaningful information as the content of the communication itself and allow eavesdroppers to uniquely identify users and their activities. Hence, by exposing the IP addresses and by analyzing patterns of the network traffic, a malicious entity can deanonymize most online communications. While content confidentiality has made significant progress over the years, existing solutions for anonymous communication which protect the network metadata still have severe limitations, including centralization, limited security, poor scalability, and high-latency. As the importance of online privacy increases, the need to build low-latency communication systems with strong security guarantees becomes necessary. Therefore, in this thesis, we address the problem of building multi-purpose anonymous networks that protect communication privacy. To this end, we design a novel mix network Loopix, which guarantees communication unlinkability and supports applications with various latency and bandwidth constraints. Loopix offers better security properties than any existing solution for anonymous communications while at the same time being scalable and low-latency. Furthermore, we also explore the problem of active attacks and malicious infrastructure nodes, and propose a Miranda mechanism which allows to efficiently mitigate them. In the second part of this thesis, we show that mix networks may be used as a building block in the design of a private notification system, which enables fast and low-cost online notifications. Moreover, its privacy properties benefit from an increasing number of users, meaning that the system can scale to millions of clients at a lower cost than any alternative solution

The Ground Is Lava!

The Ground Is Lava! is a three dimensional video game written in C++ that uses OpenGL as its graphics API. The game is competitive, with two to four players controlling characters from a first-person perspective. The project implements multiple graphics technologies in order to achieve a consistent, pleasing visual style, including shadow mapping, sky rendering, and procedural animation. The engine built to power the game was developed in a flexible manner, allowing the code to be reused for future projects