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Trustworthy Distributed Search and Retrieval over the Internet

Trustworthy Distributed Search and Retrieval over the Internet. Presented by Yung-Ting Chuang. Research conducted in collaboration with Isai Michel Lombera, Louise E. Moser and P. M. Melliar-Smith Supported in part by NSF Grant CNS 10-16103. Overview. iTrust Introduction

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Trustworthy Distributed Search and Retrieval over the Internet

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  1. Trustworthy Distributed Search and Retrieval over the Internet Presented by Yung-Ting Chuang Research conducted in collaboration with Isai Michel Lombera, Louise E. Moser and P. M. Melliar-Smith Supported in part by NSF Grant CNS 10-16103

  2. Overview • iTrust • Introduction • Implementation of iTrust • Performance evaluation • Conclusion and future work WORLDCOMP’2011 iTrust Yung-Ting Chuang

  3. iTrust vs Centralized Search Engine • Nowadays we use centralized search engines (Google, Yahoo, Bing, etc) • Benefits • Drawbacks • iTrust – distributes metadata and request to random participating nodes • Benefits • Drawbacks WORLDCOMP’2011 iTrust Yung-Ting Chuang

  4. Source of Information Distribution of Metadata WORLDCOMP’2011 iTrust Yung-Ting Chuang

  5. Source of Information Request Encounters Metadata Requester of Information Distribution of a Request WORLDCOMP’2011 iTrust Yung-Ting Chuang

  6. Source of Information Requester of Information Retrieval of Information Request Matched WORLDCOMP’2011 iTrust Yung-Ting Chuang

  7. iTrust Implementation WORLDCOMP’2011 iTrust Yung-Ting Chuang

  8. Web Server Foundation • cURL - inter-node communication and resource-specific actions • Follows HTTP redirects • SQLite - stores node, metadata, membership, and resources • Rapid deployment • Minimal local write privilege • Constrains enforcement • Session module - tracks and distinguishes users • Log module – for debugging and simulation • PECL - inter-node search and requests • Send POST statement WORLDCOMP’2011 iTrust Yung-Ting Chuang

  9. Application Infrastructure • Metadata functions XML • Senders: scan the resources and creates an XML list • Receivers: scan and insert sources into current node • Helper functions: • Inserts nodes into the membership • Insert keywords into the database • Upload or fetch resources • Node querying • Java jar files • Apache Tika packages • Apache Lucene packages • WordNet dictionary WORLDCOMP’2011 iTrust Yung-Ting Chuang

  10. Public Interface • Computer interfaces • Handles inter-node communication (ex. queries, resource distribution, and metadata list distribution) • Use inbox-type fashion to distribute/read request. • Human interfaces • Add nodes or metadata keywords • Generates requests • Provide feedback WORLDCOMP’2011 iTrust Yung-Ting Chuang

  11. Prototype Implementation of iTrust WORLDCOMP’2011 iTrust Yung-Ting Chuang

  12. Prototype Implementation of iTrust WORLDCOMP’2011 iTrust Yung-Ting Chuang

  13. Prototype Implementation of iTrust WORLDCOMP’2011 iTrust Yung-Ting Chuang

  14. Performance Evaluation • Assume: • All nodes have the same membership set • Internet is reliable • All nodes has enough memory to store sources • Variables: • Membership contains n participating nodes • Metadata are distributed to m nodes • Requests are distributed to r nodes • Proportion x of participating nodes are operational WORLDCOMP’2011 iTrust Yung-Ting Chuang

  15. Probabilistic Analysis • Probabilities: • 1st node has the metadata and is operational: mx • No match on 1st trial: 1- mx= n-mx • No match on 2nd trial: n-mx-1 • No match on rth trial: n-mx-r+1 n n n n-1 n-r+1 WORLDCOMP’2011 iTrust Yung-Ting Chuang

  16. Probabilistic Analysis • Probability q of no match on r trials: q = n-mxn-mx-1 … n-mx-r+1 n n-1 n-r+1 • Probability p of a match on r trials: p = 1 - n-mxn-mx-1 … n-mx-r+1, where n n-1 n-r+1 • If mx+r > n, then p = 1 n ≥ mx+r WORLDCOMP’2011 iTrust Yung-Ting Chuang

  17. Simulation Results • libCURL - URL transfer library for transferring data • Steps our program performed: • Clears database • Adds nodes • Uploads a file and creates metadata • Distributes metadata • Selects nodes for requests at random • If at least one node replies, program returns 1; Else program returns 0 WORLDCOMP’2011 iTrust Yung-Ting Chuang

  18. Performance Evaluation Results WORLDCOMP’2011 iTrust Yung-Ting Chuang

  19. Performance Evaluation Results WORLDCOMP’2011 iTrust Yung-Ting Chuang

  20. Conclusion and Future Work • Conclusion: • Achieve high probability of match • Match remains high even some nodes are subverted • We plan to evaluate the effectiveness, efficiency, scalability, and reliability in PlanetLab • We are investigating possible attacks on iTrust and countermeasures to such attacks • We are investigating other implementations of iTrust based on SMS • We plan to make the iTrust source code, tools, documentation, freely available WORLDCOMP’2011 iTrust Yung-Ting Chuang

  21. Questions? Comments? • Our iTrust website: • http://itrust.ece.ucsb.edu • Contact information: • Yung-Ting Chuang: ytchuang@ece.ucsb.edu • Isai: imichel@ece.ucsb.edu • Our project is supported by NSF: CNS 10-16193 WORLDCOMP’2011 iTrust Yung-Ting Chuang

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