Kabushiki Kaisha Toshiba

Kabushiki Akisha Toshiba

Koichiro Akiyama

Toru Kambayashi

Yasuhiro Goto

Shuichi Tsujimoto

Yoshihiro Ohmori

Yutaka Handa

Takeshi Saito

Satoshi Ito

Mikio Hashimoto

Kazuo Sumita

Toshihiro Sugaya

Hideyuki Aisu

Hideki Hirakawa

Naoki Endoh

Tooru Kamibayashi

Shinichiro Hamada

Toshiyuki Kito

Yuichi Komano

Hideki Tsutsui

An encryption device includes one or more hardware processors functioning as the following units. A unit acquires, as a public key, n-variable indeterminate equations X having coefficients with a predetermined degree of a univariate polynomial ring F[t] on a finite field F. A unit embeds a plaintext m into coefficients of n-variable plaintext polynomial factors m having coefficients with a predetermined degree of the F[t]. A unit generates an n-variable plaintext polynomial M by multiplying the n-variable plaintext polynomial factors mwhose number is one or more. A unit randomly generates n-variable polynomials s(k=1, 2), n-variable polynomials r, and noise polynomial e, each having coefficients with a predetermined degree of the F[t]. A unit generates a ciphertext cby executing an operation including at least one of adding, subtracting, and multiplying the s, the r, the e, and the X to, from, or by the M.

Encryption device, decryption device, encryption method, decryption method, and computer program products

An encryption device includes hardware processors to: acquire a public key including an identification polynomial f(t) and a multivariable indeterminate equation X having elements of a ring F[t]/g(t) as coefficients; disperse and embed a message m as coefficients of plaintext polynomial factors mhaving, as coefficients, polynomials with a limited degree among the elements of the ring; generate a plaintext polynomial M by multiplying the plaintext polynomial factors m; randomly generate a random polynomial r having as a coefficient an element of the ring; randomly generate a noise polynomial e having as coefficients polynomials with a limited degree among the elements of the ring; and generate a ciphertext by encryption processing of performing an operation including adding, subtracting, or multiplying the identification polynomial f(t), the random polynomial r, the noise polynomial e, and the multivariable indeterminate equation X to, from, or by the plaintext polynomial M.

Encryption device, decryption device, encryption method, decryption method, encryption program product, and decryption program product

In a symmetric encryption apparatus according to an embodiment, a storage unit stores a symmetric key formed from a plurality of elements of a first polynomial ring. A plaintext acceptance unit accepts input of plaintext information. A plaintext polynomial generation unit generates a plaintext polynomial by embedding the plaintext information whose input has been accepted in at least one of terms of a polynomial in a subspace of the first polynomial ring. A mask polynomial generation unit generates a mask polynomial having the symmetric key as a solution based on a second commutative ring defined over the first polynomial ring. An encryption unit generates a ciphertext using the plaintext polynomial and the mask polynomial.

Symmetric encryption apparatus and storage medium, and symmetric decryption apparatus and storage medium

A digital signature generation apparatus includes memory to store finite field Fand section D(u(s, t), u(s, t), s, t) as secret key, section being one of surfaces of three-dimensional manifold A(x, y, s, t) which is expressed by x-coordinate, y-coordinate, parameter s, and parameter t and is defined on finite field Fq, x-coordinate and y-coordinate of section being expressed by functions of parameter s and parameter t, calculates hash value of message m, generates hash value polynomial by embedding hash value in 1-variable polynomial h(t) defined on finite field F, and generates digital signature D(U(t), U(t), t) which is curve on section, the x-coordinate and y-coordinate of curve being expressed by functions of parameter t, by substituting hash value polynomial in parameter s of section.

Digital signature generation apparatus, digital signature verification apparatus, and key generation apparatus

A decryption apparatus includes a section assignment unit which assigns a section D to a plurality of encrypted texts F(x,y,t) (i=1, . . . , k), a one-variable polynomial arithmetic unit which subtracts L pairs of polynomials h(t) and h(t) after the assignment, and a greatest common divisor arithmetic unit which obtains the greatest common divisor &#x3c6;(t) of L polynomials g(t)(=h(t)&#x2212;h(t)) (j=1, . . . , L) as a result of the subtraction.

Encryption apparatus, decryption apparatus, key generation apparatus, and storage medium

A digital content editing apparatus that edits a content having license information defining a grant for a reusing operation or a multiple content including a plurality of the contents includes: a reuse license processor that obtains a constraint indicative of a condition on reuse between a content or the multiple content and a content other than the content or the multiple content from the license information of the content or the multiple content; an instruction generator that generates an operation execution instruction of reusing the content or the multiple content according to the constraint obtained by the reuse license processor; a reusing unit that reuses the content or the multiple content based on the operation execution instruction generated by the instruction generator; and an editor that edits the content or the multiple content reused by the reusing unit.

Apparatus and method for digital content editing

A playlist acquisition unit acquires a playlist including a view segment of contents for a user. The view segment has a start position and an end position in the contents. A copyright information acquisition unit acquires copyright information of the contents from a copyright management apparatus via a network. The copyright management apparatus manages copyright information of each content. A view right information acquisition unit acquires view right information of the user to view the contents. A viewable playlist composition unit composes a viewable playlist by editing the playlist using the copyright information and the view right information. The viewable playlist includes restriction information of the view segment.

Playlist composition apparatus, copyright management apparatus and view terminal apparatus

A key generating apparatus generates a fibration X(x, y, t)=0 of an algebraic surface X serving as a part of a public key and defined on a finite field F(where q=p[p is a prime number and r is an extended degree]) and a private key which is two sections Dand Dcorresponding to the fibration X(x, y, t)=0. The fibration X(x, y, t) is generated such that a term (c(t)xy) of xyhaving a 1-variable polynomial c(t) of t as a coefficient is included in the fibration X(x, y, t).

Key generating apparatus, program, and method

A method whereby an encryption apparatus encrypts a message on the basis of a fibration X(x, y, t) serving as a public key when private keys are two or more sections corresponding to fibration X(x, y, t)=0 of an algebraic surface X, the method comprises embedding plaintext M obtained by concatenating the message to a random number as the coefficients of plaintext polynomial M(t) of degree l&#x2212;1 or less, and generating encrypted text F=E(M, p, q, f, X) from the plaintext polynomial M(t) by an encrypting process of performing operations including at least one of addition, subtraction, and multiplication of random polynomials p(x, y, t), q(x, y, t), a random irreducible polynomial f(t) of degree l or more, and the fibration X(x, y, t) with respect to the plaintext polynomial M(t).

Encryption apparatus, decryption apparatus, and method

An information recording apparatus comprises an encryption section encrypting contents information and also a license condition referred to to limit use of the contents information and a decoding key for decoding the encrypted contents information to generate license information, and a recording section recording the encrypted contents information and the generated license information on a recording medium. An information reproducing apparatus comprises a decoder unit decoding the license information recorded on the recording medium using a second decoding key for decoding the license information and deciding on the basis of the license condition contained in the decoded license information whether the contents information can be used. If it is decided that the contents information can be used, the encrypted contents information recorded on the recording medium is decoded using the first decoding key contained in the decoded license information.

Information recording apparatus, information reproducing apparatus, and information distribution system

A packet filtering apparatus includes a first network interface which receives a first packet from a communication device located in a first network, and a sender information acquiring unit which acquires sender information including at least one of security information about the communication device and authentication information about a user of the communication device. The packet filtering apparatus also includes an evaluation information creator which creates evaluation information indicating security evaluation of the communication device based on an evaluation criterion for the sender information, an evaluation information adder which adds the evaluation information to the first packet to generate a second packet, and a second network interface which transmits the second packet to a second network.

Packet filtering apparatus, packet filtering method, and computer program product

According to each embodiment of this invention, an encryption apparatus, decryption apparatus, and key generation apparatus based on a public-key cryptographic scheme whose security is based on the divisor finding problem of obtaining a divisor on an algebraic surface which is a difficult problem that has not been solved by contemporary mathematics are realized by an arrangement using, as a private key, a section D of algebraic curves (divisors) on a fibration X(x, y, t) of an algebraic surface X. This makes it possible to create a public-key cryptographic scheme which can ensure security even in the advent of a quantum computer, can be securely realized by even current computers, and can be realized in a low-power environment.

Growing community of inventors

Tokyo, Japan

Koichiro Akiyama