Sybilproof Reputation Mechanisms

Eric Friedman
School of Operations Research and Industrial Engineering
Cornell University


Wednesday, November 16, 2005
4:30 - 5:45 PM
Terman Engineering Center, Room 453


Abstract:

Ranking and reputation systems have become central in many important areas. Perhaps the most prominent is the Pagerank ranking method used by Google, although other rankings mechanisms are of increasing importance in P2P systems. Unfortunately, these systems have been under increasing attacks and attempts to manipulate them.

In this talk, I will discuss an axiomatic approach to developing more robust ranking and reputation systems. Our results show that any symmetric method (such as the one used by Google) can be easily manipulated, while a class of flow and path based methods are more difficult to manipulate. I will also discuss some preliminary studies on the manipulability of Pagerank, based on a large sample of the world wide web graph. (This talk is based on joint work will Alice Cheng at Cornell.)

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Operations Research Colloquia: http://or.stanford.edu/oras_seminars.html