Kabushiki Kaisha Toshiba

Kenji Ohkuma

Hirofumi Muratani

Yoshikazu Hanatani

Tomoko Yonemura

Taichi Isogai

Kenichiro Furuta

Atsushi Shimbo

Yuichi Komano

Shinichi Kawamura

Fumihiko Sano

Hanae Ikeda

Kouichi Ichimura

Kentaro Torii

Mikio Fujii

Hayato Goto

Noritsugu Shiokawa

Masahiko Motoyama

An arithmetic device includes an input unit inputting data that are elements of a group; a converting unit is configured, when the input data are in a second representation, to convert the input data into a first representation and to perform arithmetic operation on the converted first representation using an operand in the first representation in which at least one subcomponent is a zero element to convert the converted first representation into first converted data expressed in the first representation, and when the input data are in the first representation, to perform arithmetic operation on the input data using the operand in the first representation in which at least one subcomponent is a zero element to convert the input data into second converted data expressed in the first representation; and an operating unit that performs arithmetic processing on the first or the second converted data using secret information.

Arithmetic device, method, and program product

According to one embodiment, a representation converting unit converts a set of n elements (h, h, . . . , h) (h: a member of a finite field F, 0&#x2266;i&#x2266;n&#x2212;1) that is a projective representation of a member g of an n-th degree algebraic torus T(F) (n: positive integer, p: prime number, m: positive integer) into a limited projected representation expressed by a set of n elements (h', h&#x2032;, . . . , h&#x2032;) (h&#x2032;: a member of the finite field F, 0&#x2266;i&#x2266;n&#x2212;1) in which at least one element out of the n elements is a zero element 0 or an identity element 1. An arithmetic unit omits part of Foperation that is arithmetic operation in the finite field Fbased on a fact that an element in the set of n elements (h&#x2032;, h&#x2032;, . . . , h&#x2032;) represented by the limited projective representation is a zero element '0' or an identity element '1' when performing Foperation that is arithmetic operation of a finite field Fin combination with the Foperation.

Arithmetic device

A compressing unit compresses an element on an algebraic torus into affine representation according to a compression map. A determining unit determines whether a target element on the algebraic torus to be compressed is an exceptional point representing an element on the algebraic torus that cannot be compressed by the compression map. The compressing unit generates, when it is determined that the target element is the exceptional point, a processing result including exceptional information indicating that the target element is the exceptional point, and generates, when it is determined that the target element is not the exceptional point, a processing result including affine representation obtained by compressing the target element according to the compression map.

Apparatus for performing data compression processing using algebraic torus

In a computing device that calculates a square of an element in a finite field, a vector representation of the element in the finite field is accepted. The vector representation includes a plurality of elements. The computing device performs a multiplication operation on a base field using the accepted elements, and obtains a multiplication value. The multiplication operation is determined by a condition under which the element in the finite field is placed in an algebraic torus. The computing device performs an addition and subtraction operation using the obtained multiplication value and the accepted elements, and obtains a calculation result of the square of the element. The addition and subtraction operation is determined by the condition. The computing device then outputs the calculation result.

Exponentiation calculation apparatus and method for calculating square root in finite extension field

When converting an affine representation representing a 2r-th degree algebraic torus T(F) (r is a prime number, and q is an integer) to a projective representation representing a quadratic algebraic torus T(F), a representation converting apparatus acquires member (c, c, . . . , c), (cis a member of a finite field F, where 0&#x2266;i&#x2266;r&#x2212;2) of a 2r-th degree algebraic torus T(F) represented by the affine representation. The apparatus performs a multiplication operation on the acquired member. The multiplication operation is determined by a condition under which a member of a quadratic algebraic torus T(F) is included in the 2r-th degree algebraic torus T(F), a modulus and a base of a quadratic extension, and a modulus and a base of an r-th degree extension. The representation converting apparatus then performs an addition and subtraction operation determined by the condition, the moduli, and the bases.

Representation converting apparatus, arithmetic apparatus, representation converting method, and computer program product

An encryption processing unit executes an arithmetic operation decided in advance and outputs an arithmetic result as an element on an algebraic torus. A compressing unit outputs, when the arithmetic result is an exceptional point representing an element on the algebraic torus that cannot be compressed by a compression map for compressing an element on the algebraic torus into affine representation, a compression result obtained by compressing the arithmetic result according to the compression map and outputs, when the arithmetic result is the exceptional point, an element belonging to a specific set decided in advance that does not overlap a set to which a compression result obtained by compressing the arithmetic result, which is not the exceptional point, belongs.

Apparatus and computer program product for performing data compression processing using algebraic torus

In the method of the present invention, one of each pair of photons connected through entanglement is distributed to a transmitting station, relay stations and a receiving station. After the photons reach secure sites, such as the relay stations, a base for detecting photons is determined between adjacent sites, and then photons are detected in each site, which makes it possible to obtain a secret key used for secure information transmission between relay stations using bases coincide with each other every time. Also, in the present invention, a high-quality random number sequence serving as a secret key is automatically generated in a physical manner every time by detecting a superposition state of an entanglement and procedures corresponding to those in which a secret key itself is transmitted in a form of a quantum cryptogram are performed.

Secret key distribution method and secret key distribution system

A microscope includes a photon source which sequentially generates sets of quantum-mechanically entangled photons including at least two photons, a lens which focuses a set of photons, an actuator which varies a relative distance between a focal position of the lens and a specimen with a minute displacement, a detector detecting photons transmitted through or scattered by the specimen, and a counter counting coincidence detections of n-numbers of photons with the detector during a gating time which is set so that a rate that a number of photons detected during thereof belong to a single set of quantum-mechanically entangled photons exceeds a predetermined rate depending on the varied relative distance.

Microscope using quantum-mechanically entangled photons

In each stage, multiple parallel nonlinear transformation modules each perform local lower-level diffusion, then a diffusion module performs higher-level diffusion over the block width and multiple parallel nonlinear transformation modules each perform local lower-level diffusion. This operation is repeated a predetermined number of times corresponding to the number of stages. Each nonlinear transformation module is formed into the nested SPN structure by arranging alternately nonlinear transformation modules and a diffusion module. The diffusion module performs linear transformation for spreading the state of at least one bit in input data to the preceding nonlinear transformation modules to at least one bit in input data to the succeeding nonlinear transformation modules.

Encryption apparatus and method, and decryption apparatus and method based on block encryption

An encryption apparatus for block data, comprises a first processing unit randomizing the block data in units of first portions obtained by dividing the block data, and a second processing unit diffusing the block data output from the first processing unit with respect to a second portion of the block data which is wider than the first portion. The first processing unit comprises first nonlinear processing units nonlinearly transforming the block data in units of the first portions. The second processing unit comprises a first linear diffusion processing unit linearly diffusing the second portion of the block data. At least one of the first nonlinear processing units comprises second nonlinear processing units nonlinearly transforming the block data in units of the first portions, and a second linear diffusion processing unit linearly diffusing the second portion of the block data.

Expanded key schedule circuit for common key encryption system in which expanded keys are used in a predetermined order in data randomizing process for encryption and in a reversed order in data randomizing process for decryption, comprises round processing circuits connected in series. The round processing circuits subject the common key or sub key of a previous stage to a round function to output a sub key. The sub key of the last stage is equal to the common key. The expanded keys are generated from the sub keys.

Growing community of inventors

Kanagawa, Japan

Kenji Ohkuma