Bounds on Key Appearance Equivocation for Substitution Ciphers

dc.creatorBorissov, Yuri
dc.creatorLee, Moon Ho
dc.date2006-12-12
dc.date2007-01-19
dc.date.accessioned2026-07-07T08:18:05Z
dc.date.available2026-07-07T08:18:05Z
dc.descriptionThe average conditional entropy of the key given the message and its corresponding cryptogram, H(K|M,C), which is reffer as a key appearance equivocation, was proposed as a theoretical measure of the strength of the cipher system under a known-plaintext attack by Dunham in 1980. In the same work (among other things), lower and upper bounds for H(S}_{M}|M^L,C^L) are found and its asymptotic behaviour as a function of cryptogram length L is described for simple substitution ciphers i.e. when the key space S_{M} is the symmetric group acting on a discrete alphabet M. In the present paper we consider the same problem when the key space is an arbitrary subgroup K of S_{M} and generalize Dunham's result.
dc.description3 pages, typos corrected, submitted to IEEE Transactions on Information Theory
dc.identifierhttps://arxiv.org/abs/cs/0612064
dc.identifierhttp://arxiv.org/abs/cs/0612064
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/134310
dc.subjectInformation Theory
dc.subjectCryptography and Security
dc.subjectE.4; H.1.1
dc.titleBounds on Key Appearance Equivocation for Substitution Ciphers
dc.typetext

Files

Collections