Presentation 2012-07-20
An Improved Algorithm for Approximate GCD Problems
Atsushi TAKAYASU, Noboru KUNIHIRO,
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Abstract(in English) In this paper, we analyze multivariate approximate common divisor problem (ACDP), given approximate multiples of the integer and we recover the integer. So far, via lattice based Coppersmith's theorem, the polynomial time ACDP algorithms have been proposed. In 2001, Howgrave-Graham proposed the polynomial time algorithms for ACDP as long as the tolerated errors are sufficiently small, when given two approximate multiples. In 2011, Cohn and Heninger gave the multivariate generalization of Howgrave-Graham's algorithm, when given plural approximate multiples. In this paper, we analyze only partially approximate common divisor problem (PACDP) when given one exact multiple of the integer. We propose the improved polynomial time algorithm by Cohn and Heninger when given plural approximate multiples. Cohn and Heninger revealed that PACDP can be solved when (α_1+…+α_n)/n<β^<(n+1)/n>. We change the lattice construction by Cohn and Heninger's algorithm and improve the condition ^n√<α_1…α_n><β^<(n+1)/n>. In the left hand side of the inequality, where is the arithmetic mean of α_1,...α_n in Cohn and Heninger's condition become the geometric mean of α_1,...α_n in our condition. Our algorithm can be applied to broader context. Moreover, considering the multivariate generalization of Howgrave-Graham's algorithm, our condition is more natural than Cohn and Heninger's condition.
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Keyword(in English) approximate-GCD / lattice / Coppersmith's theorem
Paper # ISEC2012-35,SITE2012-31,ICSS2012-37,EMM2012-27
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Committee ICSS
Conference Date 2012/7/12(1days)
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Language JPN
Title (in Japanese) (See Japanese page)
Sub Title (in Japanese) (See Japanese page)
Title (in English) An Improved Algorithm for Approximate GCD Problems
Sub Title (in English)
Keyword(1) approximate-GCD
Keyword(2) lattice
Keyword(3) Coppersmith's theorem
1st Author's Name Atsushi TAKAYASU
1st Author's Affiliation The University of Tokyo()
2nd Author's Name Noboru KUNIHIRO
2nd Author's Affiliation The University of Tokyo
Date 2012-07-20
Paper # ISEC2012-35,SITE2012-31,ICSS2012-37,EMM2012-27
Volume (vol) vol.112
Number (no) 128
Page pp.pp.-
#Pages 6
Date of Issue