1. Freenet: A Distributed Anonymous Information Storage and Retrieval System Josh Colvin CIS 590, Fall 2011

2. What are the goals of Freenet? Anonymity Repudiability Resilience Efficiency Decentralization

3. Locating Files File Keys – Keyword-signed key (KSK) – Signed-subspace key (SSK) – Content-hash key (CHK) Issues

4. Architecture Nodes – Data stores – Routing table Requests – File key – Hops-to-live

5. Data Retrieval A B E D F C

6. Data Storage Similar algorithm used in retrieval Promotes efficiency and redundancy Protects against attacks

7. Data Management Data permanency – Dropping unused data Datastore encryption

8. Network Expansion Adding new nodes Distribution complications Registering in routing tables

9. 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

10. Security Primary goal is protecting anonymity Specific threats – File Modification Infeasible for SSK or CHK data – Denial of service attack Hash Cash Datastore partitioning

11. Goals Recap Anonymity Repudiability Resilience Efficiency Decentralization

12. Questions?