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SUMMARY:Key amplification in unstructured networks - Shishir Nagaraja\, Co
 mputer Laboratory\, University of Cambridge
DTSTART:20071030T161500Z
DTEND:20071030T171500Z
UID:TALK7970@talks.cam.ac.uk
CONTACT:Saar Drimer
DESCRIPTION:There are a number of scenarios where users wishing to communi
 cate\, share a weak secret. Often\, they are also part of a common social 
 network. Connections (edges) from the social network are represented as sh
 ared link keys between participants (vertices). We propose several mechani
 sms that utilise the graph topology of such a network\, to increase the en
 tropy of weak pre-shared secrets. Our proposals are based on using random 
 walks to efficiently identify a chain of common acquaintances between Alic
 e and Bob\, each of which contribute entropy to the final key. Our mechani
 sms exploit one-wayness and convergence properties of Markovian random wal
 ks to\, firstly\, maximize the set of potential entropy contributors\, and
  second\, to resist any contribution from dubious sources by exploiting th
 e community information characteristically present in real world network t
 opologies.
LOCATION:Lecture Theatre 2\, Computer Laboratory\, William Gates Building
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