Coding Theorems for the Shannon Cipher System With a Guessing Wiretapper and Correlated Source Outputs
Yutaka Hayashi and Hirosuke Yamamoto
IEEE Trans. on Information Theory, Vol. 54, No.6, pp.2808-2817, June 2008
- The security level of the Shannon cipher system is traditionally measured by equivocation (1/N)H(Y|Z), where Y is a secret plaintext with length N and Z is its cryptogram. But, Merhav and Arikan have considered another security criterion, which is measured by the number of guesses needed for a wiretapper to uncover Y from Z. Merhav has also considered the third security criterion, which measured by the probability of correct guess of a wiretapper. On the other hand, in the case of the traditional security criterion, Yamamoto has treated a coding problem for correlated source outputs X and Y such that only X is secret against wiretappers and only Y must be transmitted to a legitimate receiver. In this correspondence, coding theorems are proved for the case that Yamamoto's coding problem is applied to Merhav-Arikan's security criterion or Merhav's security criterion.
- Index Terms : Coding theorem, correlated sources, guessing wiretapper, perfect secrecy, Shannon cipher system.
- DOI: 10.1109/TIT.2008.921707