Presentation 2014-07-03
Security of RSA with Many Decryption Exponents
Atsushi TAKAYASU, Noboru KUNIHIRO,
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Abstract(in English) When we use small secret exponents, RSA becomes efficient for its decryption cost and signature generation cost. However, it is widely known that too small secret exponents enables attackers to factor RSA modulus N efficiently. Boneh and Durfee used lattice based Coppersmith's method and proposed polynomial time algorithm to factor the modulus when d < N^<1-1/√<2>>. So far, the variants of the problem have been considered when there are k encryption/decryption exponents pairs. Howgrave-Graham and Seifert solved diophanine approximation problems and proposed a polynomial time algorithm to factor RSA modulus. When k → ∞, the algorithm works for even full size decryption exponents. Aono used the Coppersmith's method and proposed an algorithm. Though Aono's algorithm is better than the all previous ones for small k ≧ 2, when k → ∞, the algorithm only works when d < N^<3/4>. In this paper, we use the Coppersmith's method as Aono and propose improved algorithm. Our algorithm works when d < N^<1-√<2/(3k+1)>>.
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Keyword(in English) RSA / Lattices / Coppersmith's method
Paper # ISEC2014-19,SITE2014-14,ICSS2014-23,EMM2014-19
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Conference Information
Committee SITE
Conference Date 2014/6/26(1days)
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Registration To Social Implications of Technology and Information Ethics (SITE)
Language JPN
Title (in Japanese) (See Japanese page)
Sub Title (in Japanese) (See Japanese page)
Title (in English) Security of RSA with Many Decryption Exponents
Sub Title (in English)
Keyword(1) RSA
Keyword(2) Lattices
Keyword(3) Coppersmith's method
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 2014-07-03
Paper # ISEC2014-19,SITE2014-14,ICSS2014-23,EMM2014-19
Volume (vol) vol.114
Number (no) 116
Page pp.pp.-
#Pages 4
Date of Issue