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SUMMARY:Weightedness and Structural Characterization of Hierarchical Simpl
 e Games - Tatiana Gvozdeva\, NTU Singapore
DTSTART:20120502T130000Z
DTEND:20120502T140000Z
UID:TALK38083@talks.cam.ac.uk
CONTACT:Microsoft Research Cambridge Talks Admins
DESCRIPTION:Secret sharing schemes—first introduced by Shamir (1979) and
  now widely used in many cryptographic protocols—is a tool designed for 
 securely storing information that is highly sensitive and highly important
 . \nThe set of all authorised coalitions of a secret sharing scheme is kno
 wn as the access structure. It can also be modeled by a simple game. In th
 e \ntheory of simple games seniority of players is usually modeled by assi
 gning  to players different weights.  Shamir (1979) also suggested (indepe
 ndently from any literature on simple games) to model seniority of users i
 n access structure by assigning weights to them. However this approach was
  not actively pursued. Instead\, Simmons (1990) introduced the concept of 
 a hierarchical access structures. In this talk we will compare these two d
 ifferent  approaches to model seniority of players. Also we will character
 ize hierarchical  access structures from game theoretical point of view.
LOCATION:Small lecture theatre\, Microsoft Research Ltd\, 7 J J Thomson Av
 enue (Off Madingley Road)\, Cambridge
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