Recently, the researchers behind the Freenet project proposed a novel protocol for efficient and fully decentralized routing in these types of networks. Researchers of the Colorado Research Institute for Security and Privacy investigated the security of this new protocol. Given that adversaries can often easily participate in open, large-scale and fully decentralized networks, the new protocol would be particularly useful if it would be difficult for malicious participants to disrupt its operation.
Using the 20 machines of the Debian GNU/Linux lab in John Greene Hall a network with over 800 Freenet nodes was simulated. The simulation showed that a relatively weak participating adversary can render the overlay ineffective without being detected, resulting in significant data loss due to a load imbalance caused by the adversary. Detailed simulation results are available on the "Pitch Black" project webpage.
Various countermeasures to detect, thwart or limit the attack were studied; however, so far an effective countermeasure that would preserve the efficiency and decentralized nature of the original protocol has not been found. Additional details about the research have been published in our paper Routing in the Dark: Pitch Black which was published at ACSAC 2007.
Our future plans include the design and implementation of alternative, fully-decentralized routing algorithms using the GNUnet framework. The Debian GNU/Linux lab will continue to be used as a platform for simulating the resulting designs.
This research was done by Nathan Evans, Dr. Chris GauthierDickey and Dr. Christian Grothoff.