Rate-distortion theory for the Shannon cipher system

Abstract

Rate distortion theory is considered for the Shannon cipher system (SCS). The admissible region of cryptogram rate R, key rate R/sub k/, legitimate receiver's distortion D, and wiretapper's uncertainty h is determined for the SCS with a noisy channel. Furthermore, inner and outer bounds of the admissible region of R, R/sub k/, D, and wiretapper's attainable minimum distortion D/spl tilde/ are derived for the SCS with a finite discrete source and a noiseless channel.