Departmental Honors Advisor

Abstract

In this thesis we argue that content distribution in the face of censorship is an appropriate and feasible application of active networking. In the face of a determined and powerful adversary, every fixed protocol can become known and subsequently monitored, blocked, or its member nodes identified and attacked. Rapid and diverse protocol change is key to allowing information to continue to flow. Typically, decentralized protocol evolution is also an important aspect in providing censor-resistance for publishing networks. These goals can be achieved with the help of active networking techniques, by allowing new protocol implementations, in the form of mobile code, to spread throughout the network. A programmable overlay network can provide protocol change and decentralized protocol evolution. Such a system, however, will need to take steps to ensure that programmability does not present excessive security threats to the network. Runtime isolation, protocol confidence ratings, encryption, and resource control are vital in this respect. We have prototyped such a system as an extension to Freenet, a storage and retrieval system whose goals include censor resistance and anonymity for informa-tion publishers and consumers. Our prototype implements many of the mechanisms discussed in this thesis, indicating that our proposed ideas are feasible to imple-ment. i