Onion routing

Onion routing is a technique for anonymous communication over a computer network. In an onion network, messages are encapsulated in layers of encryption, analogous to the layers of an onion. The encrypted data is transmitted through a series of network nodes called "onion routers," each of which "peels" away a single layer, revealing the data's next destination. When the final layer is decrypted, the message arrives at its destination. The sender remains anonymous because each intermediary knows only the location of the immediately preceding and following nodes. While onion routing provides a high level of security and anonymity, there are methods to break the anonymity of this technique, such as timing analysis. History Onion routing was developed in the mid-1990s at the U.S. Naval Research Laboratory by employees Paul Syverson, Michael G. Reed, and David Goldschlag to protect U.S. intelligence communications online. It was then refined by the Defense Advanced Research Pr

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This is an introductory course to computer security and privacy. Its goal is to provide students with means to reason about security and privacy problems, and provide them with tools to confront them.

A decentralized system is one that works when no single party is in charge or fully trusted. This course teaches decentralized systems principles while guiding students through the development and testing of their own decentralized system incorporating messaging, encryption, and blockchain concepts.

This course will offer students a broad but hands-on introduction to technologies of human self-organization.

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Tor (network)

Tor, short for The Onion Router, is free and open-source software for enabling anonymous communication. It directs Internet traffic via a free, worldwide, volunteer overlay network that consists of mo

I2P

The Invisible Internet Project (I2P) is an anonymous network layer (implemented as a mix network) that allows for censorship-resistant, peer-to-peer communication. Anonymous connections are achieved

Peer-to-peer

Peer-to-peer (P2P) computing or networking is a distributed application architecture that partitions tasks or workloads between peers. Peers are equally privileged, equipotent participants in the n

Dissent in Numbers: Making Strong Anonymity Scale

Henry Nathaniel Corrigan-Gibbs, Bryan Alexander Ford

Current anonymous communication systems make a trade-off between weak anonymity among many nodes, via onion routing, and strong anonymity among few nodes, via DC-nets. We develop novel techniques in Dissent, a practical group anonymity system, to increase by over two orders of magnitude the scalability of strong, traffic analysis resistant approaches. Dissent derives its scalability from a client/server architecture, in which many unreliable clients depend on a smaller and more robust, but administratively decentralized, set of servers. Clients trust only that at least one server in the set is honest, but need not know or choose which server to trust. Unlike the quadratic costs of prior peer-to-peer DC-nets schemes, Dissent's client/server design makes communication and processing costs linear in the number of clients, and hence in anonymity set size. Further, Dissent's servers can unilaterally ensure progress, even if clients respond slowly or disconnect at arbitrary times, ensuring robustness against client churn, tail latencies, and DoS attacks. On DeterLab, Dissent scales to 5,000 online participants with latencies as low as 600 milliseconds for 600-client groups. An anonymous Web browsing application also shows that Dissent's performance suffices for interactive communication within smaller local-area groups.

2012

Seeking Anonymity in an Internet Panopticon

Bryan Alexander Ford

Internet, users often need to assume, by default, that their every statement or action online is monitored and tracked. The Dissent project at Yale University takes a collective approach to online anonymity, based on different algorithmic foundations from onion routing, offering concrete advantages, as well as some disadvantages. Dissent preserves maximum security provided only that not all of a group's servers maliciously collude against their clients. In an honest- security model in which we assume each shuffler correctly follows the protocol the output from the last shuffler offers provable anonymity among all non-colluding clients, provided at least one of the shufflers keeps its random permutation secret. A substantial body of work addresses these vulnerabilities to such active attacks. Dissent addresses the jamming problem by implementing accountability mechanisms, allowing the group to revoke the anonymity of any peer found to be attempting to jam communication maliciously while preserving strong anonymity protection for peers who follow the rules. Dissent now adopts a client/multi-server model with trust split across multiple servers, preferably administered independently. More important in practice, Dissent's client/multi-server coin-sharing design addresses network churn by making the composition of client ciphertexts independent of the set of other clients online in a given round.

Assoc Computing Machinery2015

A Location Based Routing Method for Irregular Mobile Ad Hoc Networks

Ljubica Blazevic, Jean-Yves Le Boudec

Using location information to help routing is often proposed as a means to achieve scalability in large mobile ad-hoc networks. However, location based routing is difficult when there are holes in the network topology and nodes are mobile. Terminode routing, presented here, addresses these issues. It uses a combination of location based routing (Terminode Remote Routing, TRR), used when the destination is far, and link state routing (Terminode Local Routing, TLR), used when the destination is close. TRR uses anchored paths, a list of geographic points (not nodes) used as loose source routing information. Anchored paths are discovered and managed by sources, using one of two low overhead protocols: Friend Assisted Path Discovery and Geographical Map-based Path Discovery. Our simulation results show that terminode routing performs well in networks of various sizes. In smaller networks, the performance is comparable to MANET routing protocols. In larger networks that are not uniformly populated with nodes, terminode routing outperforms existing location-based or MANET routing protocols.

2003

This course will offer students a broad but hands-on introduction to technologies of human self-organization.