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Freenet: A Distributed Anonymous Information Storage and Retrieval System. Josh Colvin CIS 590, Fall 2011. What are the goals of Freenet?. Anonymity Repudiability Resilience Efficiency Decentralization. Locating Files. File Keys Keyword-signed key (KSK) Signed-subspace key (SSK)
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Freenet: A Distributed Anonymous Information Storage and Retrieval System Josh Colvin CIS 590, Fall 2011
What are the goals of Freenet? • Anonymity • Repudiability • Resilience • Efficiency • Decentralization
Locating Files • File Keys • Keyword-signed key (KSK) • Signed-subspace key (SSK) • Content-hash key (CHK) • Issues
Architecture • Nodes • Data stores • Routing table • Requests • File key • Hops-to-live
Data Retrieval C A B D F E
Data Storage • Similar algorithm used in retrieval • Promotes efficiency and redundancy • Protects against attacks
Data Management • Data permanency • Dropping unused data • Datastore encryption
Network Expansion • Adding new nodes • Distribution complications • Registering in routing tables
Performance Analysis • Convergence • Increases as the network operates • Average path length decreases • Scalability • Pathlength scales logarithmically • Projected median of ~30 hops at 1,000,000 nodes • Fault-Tolerance • Median path length <20 at 30% node failure
Security • Primary goal is protecting anonymity • Specific threats • File Modification • Infeasible for SSK or CHK data • Denial of service attack • Hash Cash • Datastore partitioning
Goals Recap • Anonymity • Repudiability • Resilience • Efficiency • Decentralization