| The need to communicate anonymously over the Internet has increased with the proliferation of networked computers. Applications such as military communications, Web browsing, e-voting, and e-counseling for victims of abuse all require anonymous communication. Without anonymity, individuals may refrain from communicating for fear of retribution, potentially resulting in social, psychological, or financial losses, or even the loss of life.;This thesis contains a comprehensive survey and analysis of anonymous communication schemes. Analysis of the prior literature shows that there is no secure and scalable anonymous communication scheme. Previous literature has only analyzed each scheme for a subset of the known attacks. In this thesis, the analysis is extended to assess the anonymity capabilities of these schemes with respect to all known attacks. It is shown that none of the scalable anonymous communication schemes are secure.;The thesis contains a description of the design, implementation, and evaluation of a prototype anonymous communication scheme. The Buses anonymity protocol is identified as the most secure and scalable candidate protocol for a dynamic network topology. The protocol is re-designed and extended into the Practical Buses protocol, with features added to protect against all of the known attacks in the literature. New techniques are introduced to make the protocol scalable while preserving mutual anonymity. The design is extended to make the protocol more efficient, secure, and fault-tolerant. The experimental results obtained demonstrate that the Practical Buses protocol is a promising solution for anonymous network communication. |
