Presentation	2009-12-16 On Viterbi search for the maximum differential characteristic probability of a cipher with certain Feistel structure Yasutaka IGARASHI, Toshinobu KANEKO,
PDF Download Page	PDF download Page Link
Abstract(in Japanese)	(See Japanese page)
Abstract(in English)	We study a Viterbi search for the maximum differential characteristic probability (DCP_) of a symmetric-key cipher with a certain Feistel structure (CFS). DCP_ is a security index of differential cryptanalysis. The upper bound of DCP_ is given by a truncated-path search with Viterbi algorithm. The bit size of input/output of linear transformation in round function is larger than a truncation-bit size in CFS. We show that the truncated-path search gives an imaginary path as the resultant optimum path in CFS, which cannot be connected as a real path. We also propose a new search algorithm to eliminate such imaginary paths. Our algorithm can give the upper bound of DCP_ tighter than conventional one.
Keyword(in Japanese)	(See Japanese page)
Keyword(in English)	Feistel / Viterbi algorithm / differential characteristic probability / truncation
Paper #	ISEC2009-74
Date of Issue

Conference Information
Committee	ISEC
Conference Date	2009/12/9(1days)
Place (in Japanese)	(See Japanese page)
Place (in English)
Topics (in Japanese)	(See Japanese page)
Topics (in English)
Chair
Vice Chair
Secretary
Assistant

Paper Information
Registration To	Information Security (ISEC)
Language	JPN
Title (in Japanese)	(See Japanese page)
Sub Title (in Japanese)	(See Japanese page)
Title (in English)	On Viterbi search for the maximum differential characteristic probability of a cipher with certain Feistel structure
Sub Title (in English)
Keyword(1)	Feistel
Keyword(2)	Viterbi algorithm
Keyword(3)	differential characteristic probability
Keyword(4)	truncation
1st Author's Name	Yasutaka IGARASHI
1st Author's Affiliation	Faculty of Science and Technology, Tokyo University of Science()
2nd Author's Name	Toshinobu KANEKO
2nd Author's Affiliation	Faculty of Science and Technology, Tokyo University of Science
Date	2009-12-16
Paper #	ISEC2009-74
Volume (vol)	vol.109
Number (no)	337
Page	pp.pp.-
#Pages	5
Date of Issue