AG Kommunikationstheorie

Thema:

Secure and Anonymous Peer-to-Peer Random Node Lookup in Untrustworthy Environment

Abstract:

The "Internet age" poses fundamentally new threats of surveillance and restriction for communication processes. To allow anonymous and unrestricted communication, systems like the Tor anonymous communication network have been developed. On its way from transmitter to receiver, those systems send communication data through a set of randomly chosen intermediates. To successfully conceal the communication relationship, randomness and privacy of the selection process for those intermediates are essential. Today, this is realized by having a set of central trusted servers maintaining a complete list of all network participants, which can be downloaded by users. This approach, however, does not scale and requires full trust in the central servers. We developed a new secure and anonymous peer-to-peer random node lookup system, called Palaver. Palaver allows nodes in an untrustworthy computer network to discover and randomly choose nodes from the entire set of existing nodes. An attacker in control of a subset of nodes can neither gain significant influence on the selection process, nor learn which nodes have been chosen. Such selected nodes can be used to build encrypted multi-hop communication tunnels for anonymous communication, without requiring a central instance or a complete view of the network. Palaver is robust against active attacks and prevents the inadvertent leakage of information about the selected nodes, observed in competing approaches. At the same time Palaver scales well and creates merely a small overhead in network traffic.

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