Nec Corporation

Haruna Fukuda

Toshiyuki Isshiki

Hiroto Tamiya

Masahiro Nara

Toshihiko Okamura

Kengo Mori

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

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 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.

A generation apparatus converts a received key to an encoded key by using an encoding function of an error correcting code, and generates a sketch by applying a first composite transformation on received fuzzy data and the encoded key. A reconstruction apparatus receives a first sketch and a second sketch, generates a composite sketch by applying second composite transformation on the first and second sketches, and reconstruction calculates difference between the two keys used to generate the first and second sketches based on the composite sketch.

Linear sketch system, apparatus, authentication method, program, and recording medium

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

Provided is an authentication system capable of preventing determination that authentication of a person to be authenticated succeeds even though determination as to whether matching information matches registration information is not performed when authentication using two factors is performed. A determination unitdetermines whether or not the matching information matches the registration information. A signature generation unitof a clientgenerates a signature based on the message by using a signature key. A signature determination unitdetermines whether or not the signature is a correct signature by using a first verification key, a message, and the signature. When it is determined that the matching information matches the registration information and it is determined that the signature is the correct signature, the authentication determination unitdetermines that the authentication succeeds.

Authentication 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.

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Tokyo, Japan

Haruna Fukuda