Date Added: Jul 2010
In recent years, growing number of cryptosystems based on chaos have been proposed. However, most of them encounter some problems such as: low level of security and small key space. The key stream generator is the key design issue of an encryption system. It directly determines security and efficiency, but most of the proposed key streams are binary valued, and suffer from short period and limited key space. In this paper, the authors propose an n-ary key stream generator, based on hierarchical combination of three chaotic maps.