On the average number of ciphertexts for the optimal key-management tree for a frequency distribution of communication

Abstract

The average number of ciphertexts per one sessionT is an indicator of aptitude of a key-management tree T for a given frequency distribution of communication. In this paper, we estimate the weighted mean ofcT over all T 's with respect to appropriate weights as a criterion of aptitude of a key- management tree. We also give the concrete value of that mean in the case of equal weights.