Nec Corporation

Hiroto Tamiya

Toshiyuki Isshiki

Masahiro Nara

Haruna Fukuda

Toshihiko Okamura

Kengo Mori

Batnyam Enkhtaivan

Sanami Nakagawa

In order to realize encryption processing capable of suppressing the degradation of collation accuracy and reducing the risk of information leakage, a terminal apparatus for encrypting input information to be input for collation is provided, the terminal apparatus being configured to perform transformation parameter generation processing for generating a transformation parameter based on a first parameter stored in a storage area and a second parameter that is different from the first parameter, and encrypt the input information input for collation using the transformation parameter to generate encrypted input information.

Terminal apparatus, encrypted information transformation apparatus, collation system, input information encryption method, encrypted information transformation method, collation method, input information encryption program, and encrypted information transformation program

An authentication system transmits a ciphertext of authentication information from an authenticatee apparatus to an authenticator apparatus using homomorphic encryption with a public key encryption scheme, the authenticator apparatus issues a first random number to the authenticatee apparatus, the authenticatee apparatus generates a second random number and transmits to the authenticator apparatus a first element generated with a public key using the first and the second random numbers and a second element generated with a public key using the second random number, and the authenticator apparatus modifies the second element using the first random number to obtain a ciphertext of the authentication information.

Authentication system, authenticatee apparatus, authenticator apparatus, authentication method, and authentication program

Provided is a registration information generation apparatus for generating registration information based on registration-side input information including one or both of elements corresponding to a first set and elements corresponding to a second set, the registration information generation apparatus being configured to generate intermediate information by performing distribution processing for performing secret-sharing for the elements corresponding to the first set in input information, and a duplication processing for duplicating the elements corresponding to the second set in input information, and generate the registration information by replacing a sort order of elements in the intermediate information using a replacement key.

System for cancelable biometric feature data generation

An information concealing system includes: an information concealing apparatus configured to generate a pseudo-random number, convert first information into first conversion information by using the pseudo-random number, and cause a concealment information generating unit to generate first concealment information capable to reconfigure the first information, based on the first conversion information; and an information reconfiguring apparatus configured to extract information related to a seed from the first concealment information, generate a reconfiguration-side pseudo-random number, based on the information related to the seed, convert input second information into second conversion information by using the reconfiguration-side pseudo-random number, and reconfigure the first information concealed as the first concealment information, based on the second conversion information and the first concealment information.

Information concealing control apparatus, information concealing apparatus, information reconfiguration control apparatus, information reconfiguring apparatus, information concealing system, information concealing control method, information reconfiguration control method, information concealing control program, and information reconfiguration control program

A signature verification system includes: a signature apparatus configured to sign a first chameleon hash value, an unmodifiable part of the data, and a second chameleon hash value of an entirety of the data; a changing apparatus configured to change a public key for the changers of the temporary delegator to a public key for changers of an actual delegator, using a private key for the changers; a delegator changing apparatus configured to change a modifiable part of the data, using a private key for the changers of the actual delegator; and a verifying apparatus configured to verify the signature using the public key for the changers and the public key for the changers of the actual delegator.

Signature verification system, signature apparatus, signature verification method, and program

A collation systemincludes divide registered information to first information and second information, and to provide the second information to a server apparatus, perform a first step for similarity calculation between the registered information and collation information inputted for collation with the registered information, based on the collation information and the first information, send a calculation result of the first step to the server apparatus, perform a second step for the similarity calculation based on the calculation result of the first step received from a client terminal, and the second information, send a calculation result of the second step to the client terminal, and perform a third step for the similarity calculation based on the calculation result of the second step received from the server apparatus, and the first information to calculate similarity between the registered information and the collation information.

Collation system, client terminal, server apparatus, collation method, and program

The client includes a random number generation unit which generates a random number, a concealed information storage unit which stores concealed information generated by concealing registered information and the generated random number using a secret key, and a response computation unit which, on the basis of a challenge transmitted from the server, the collation information input for collation with the registered information, and the concealed information, computes a response corresponding to the challenge and including a concealed index, generated by concealing an index indicating closeness between the registered information and the collation information. The server includes a challenge generation unit which generates the challenge using a public key corresponding to the secret key, and a determination unit which uses the public key and the random number transmitted from the client to determine whether or not the response transmitted from the client corresponds to the challenge.

Collation system, client, and server

In order to provide an information concealing apparatus, an information reconfiguring apparatus, an information concealing system, an information concealing method, an information reconfiguring method, an information concealing program, and an information reconfiguring program to reduce information leakage risks, an information concealing system includes an information concealing apparatus, and an information reconfiguring apparatus. The information concealing apparatus generates a codeword capable of error-correcting concealment-side input information, generates noise including a predetermined error, and generates concealment information capable to reconfigure the concealment-side input information, by adding the concealment-side input information and the noise to the codeword. The information reconfiguring apparatus reconfigures the codeword from the concealment information, based on reconfiguration-side input information and the concealment information.

Information concealing apparatus, information reconfiguring apparatus, information concealing system, information concealing method, information reconfiguring method, information concealing program, and information reconfiguring program

In order to provide an information matching system achieving an information matching scheme that takes a lower cost and uses secure biometric information, the information matching system includes a concealment apparatus, a decryption apparatus, and a similarity calculating apparatus. The concealment apparatus transmits, to the similarity calculating apparatus, concealed information including information concealing obtained matching information by linear conversion using random numbers. The similarity calculating apparatus calculates, from obtained one or more pieces of registration information and the concealed information received from the concealment apparatus, a concealed similarity which is a value concealing a similarity between the matching information and the registration information, and to transmit the calculated concealed similarity to the decryption apparatus. The decryption apparatus calculates the similarity between the matching information and the registration information from the concealed similarity received from the similarity calculating apparatus, using the random numbers used by the concealment apparatus.

Information matching system and information matching method

A storing information generation apparatus obtains registration information and an identifier capable of identifying the registration information, to generate a first individual key from the common key and the identifier, and to generate storing information obtained by linearly converting the registration information using the common key and the first individual key. A matching information concealment apparatus obtains matching information to generate concealed matching information concealing the matching information using an encryption key. A concealed similarity calculation apparatus calculates a concealed similarity from the storing information and the concealed matching information. A decryption apparatus generates a second individual key from the common key and the identifier, and calculates a similarity between the registration information and the matching information from the concealed similarity, a decryption key corresponding to the encryption key, the common key, and the second individual key.

Provided is an encryption system that suppresses a communication cost from a key issuing system to a user and controls input to a function in the unit of data. The encryption system includes an encrypting apparatus, a signature apparatus, and a security execution apparatus. The encrypting apparatus generates pseudo-random numbers different for respective pieces of data, and encrypts the generated pseudo-random numbers together with the pieces of data. The signature apparatus regenerates the pseudo-random numbers used by the encrypting apparatus for encrypting the respective pieces of data, and generates control information for certifying validity of the pieces of the data from the regenerated pseudo-random numbers. The security execution apparatus verifies the control information based on the pseudo-random numbers obtained by decrypting ciphertexts of the pieces of the data, and calculates a function value of data obtained by decrypting the ciphertexts when the verification of the control information is successful.

Encryption system, function value calculation method, and program

A collation system, which is provided with a clientand a server, the clientincludes: a random number generation unitwhich generates a random number; a concealed information storage unitwhich stores concealed information generated by concealing registered information and the generated random number using a concealment key; and a concealed index computation unitwhich, on the basis of the collation information input for collation with the registered information and the concealed information, computes a concealed index, generated by concealing an index indicating closeness between the registered information and the collation information; the serverincludes a determination unitwhich uses a release key corresponding to the concealment key and the random number transmitted from the clientto determine whether or not the index can be acquired from the concealed index transmitted from the client

Collation system, client and server

An encryption system comprises a key generation apparatus that generates an encryption key relating to the authority to generate a ciphertext from a plaintext, a homomorphic operation key relating to the authority to execute a homomorphic operation on a ciphertext that remains encrypted and whose authority is weaker than that of the encryption key, and a decryption key relating to the authority to decrypt ciphertext; an encryption apparatus that generates a ciphertext from a plaintext using the encryption key; a homomorphic operation apparatus that executes a homomorphic operation on the ciphertext using the homomorphic operation key; and a decryption apparatus that decrypts ciphertext using the decryption key.

Growing community of inventors

Tokyo, Japan

Hiroto Tamiya