Improving Anonymity in Shared Key Primitives Based on Perfect Hash   Families
  We propose a new scheme for sharing symmetric key operations among a set of participants according to a (t,n) threshold access structure. We focus on anonymity properties of this scheme and show that this scheme provides improved values of anonymity measures than the existing ones. In particular, the scheme can provide optimal and equitable participant anonymity when it is based on balanced perfect hash families. 
Mausumi Bose and Rahul Mukerjee
cs.CR