Please use this identifier to cite or link to this item:
Title: Optimal trees for minimizing average individual updating cost
Author(s): Zhao, Yingchao 
Author(s): Guo, S.
Li, M.
Issue Date: 2015
Publisher: Elsevier
Journal: Theoretical Computer Science 
Volume: 607
Start page: 272
End page: 281
Key tree is a popular model to maintain the security of group information sharing by using a tree structure to maintain the keys held by different users. Previously, researchers proved that to minimize the worst case updating cost in case of single user deletion, one needs to use a special 2–3 tree. In this paper, we study the average case for user update. We prove that in the optimal tree, the branching degree of every node can be bounded by 3 and furthermore the structure of the optimal tree can be pretty balanced. We also show the way to construct the optimal tree when there are loyal users in the group. Finally we discuss about the weighted case where different users have different probabilities to be the first one leaving the group. We design a polynomial time algorithm to construct the optimal tree when the number of different probabilities is a constant.
DOI: 10.1016/j.tcs.2015.08.030
CIHE Affiliated Publication: Yes
Appears in Collections:CIS Publication

Files in This Item:
File Description SizeFormat
View Online128 BHTMLView/Open
Check Library Catalogue115 BHTMLView/Open
SFX Query Show full item record

Google ScholarTM




Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.