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SUMMARY:Weightedness and Structural Characterization of Hierarchical Simpl
 e Games - Tatiana Gvozdeva\, NTU Singapore
DTSTART:20120509T130000Z
DTEND:20120509T140000Z
UID:TALK38179@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
 . The set of all authorised coalitions of a secret sharing scheme is known
  as the access structure. It can also be modeled by a simple game. In the 
 theory of simple games seniority of players is usually modeled by assignin
 g  to players different weights.  Shamir (1979) also suggested (independen
 tly from any literature on simple games) to model seniority of users in ac
 cess structure by assigning weights to them. However this approach was not
  actively pursued. Instead\, Simmons (1990) introduced the concept of a hi
 erarchical access structures. In this talk we will compare these two diffe
 rent  approaches to model seniority of players. Also we will characterize 
 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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