The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 20, 2013
Filed:
Apr. 23, 2010
Eiichiro Fujisaki, Tokyo, JP;
Koutarou Suzuki, Tokyo, JP;
Eiichiro Fujisaki, Tokyo, JP;
Koutarou Suzuki, Tokyo, JP;
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Abstract
Security against CCA is improved without providing space for just improving the security against CCA in a ciphertext space. In encryption processing, a first ciphertext Cis calculated from a plaintext M and a symmetric key K; a value containing a value corresponding to the symmetric key K and a value corresponding to the first ciphertext Cis put into a collision-resistant function H to calculate a function value of the function H; and r corresponding to the function value is used to calculate second ciphertext C=r·(Σv·b)+ρ·b∈G. In decryption processing, the second ciphertext C∈Gand key information D*=α·(Σw·b*)+b*∈Gare put into a bilinear function e to calculate a function value S=e(C, D*)∈G; a value corresponding to the function value Sand the first ciphertext Care put into the collision-resistant function H to calculate a function value of the function H; and it is judged whether rcorresponding to the function value satisfies C=r·(Σv·b)+ρ·b∈G.