Fujitsu Corporation

Masaya Yasuda

Takeshi Shimoyama

Jun Kogure

Masahiko Takenaka

Yumi Sakemi

Yuka Jo

Tetsuya Izu

Jun Yajima

Ikuya Morikawa

A first code is generated from data by using a second error correction encoding method, and a second code is generated from the first code and a first random number by using a first error correction encoding method. First masked data is generated by masking registration target data by using the second code, and the first masked data is registered in a database. A third code is generated from a second random number by using the first error correction encoding method. Second masked data is generated by masking matching target data by using the third code. Synthesized data is generated by synthesizing the second masked data and the first masked data registered in the database, and the synthesized data is decoded in accordance with the first error correction encoding method and the second error correction encoding method.

Encrypted-data processing method, system, and apparatus

A memory stores therein first cryptographic information that represents an encrypted polynomial obtained by encrypting a first polynomial that corresponds to a first vector. From a terminal that receives second cryptographic information that represents an encrypted monomial obtained by encrypting a monomial generated by use of a random number, a receiver receives third cryptographic information that represents an encrypted result obtained by encrypting a result of a multiplication of a second polynomial that corresponds to a second vector by the monomial. A processor generates an encrypted polynomial that includes a result of an operation of the first vector and the second vector by use of the first cryptographic information, the third cryptographic information, and information that represents the monomial. An output interface outputs fourth cryptographic information that represents the encrypted polynomial generated by the generator.

Cryptographic processing device and cryptographic processing method

A cryptographic processing device includes a processor that generates a first encrypted polynomial, a receiver that receives cryptographic information representing a fourth encrypted polynomial, and cryptographic information representing a second random number, the fourth encrypted polynomial including a first operation result that is a result of an operation of a fifth vector and a sixth vector, the first operation result being obtained by a second encrypted polynomial and a third encrypted polynomial, wherein the second encrypted polynomial is obtained based on the first encrypted polynomial, the second random number, and a second polynomial that corresponds to a third vector obtained by adding zero to the second vector, and the third encrypted polynomial is obtained based on the fifth vector obtained by adding zero to a fourth vector. The processor generates a second operation result that is a result of an operation of the second vector and the fourth vector.

A secret data matching device includes a memory unit for storing a first secret vector obtained by concealing a first data set and a key data using a determination matrix; an obtaining unit for obtaining a second secret vector by concealing a second data set using the determination matrix; a calculating unit for calculating a residue vector which is a residue when the determination matrix is a modulus, from a difference between the first and second secret vectors; a determination unit for determining whether the first and second data sets are approximate based on the residue vector; an extracting unit for extracting the key data from the residue vector when the first data set and the second data set are approximate; a creating unit for generating a third secret vector by combining the key data and the second secret vector; and a storing unit for storing the third secret vector.

Secret data matching device, computer-readable recording medium storing program for updating secret data, and secret data updating method

A computer generates a third encrypted polynomial that corresponds to a result of encrypting a third polynomial by use of a result of multiplying a first encrypted polynomial by a second encrypted polynomial, and outputs cryptographic information that represents the third encrypted polynomial. The first encrypted polynomial is a polynomial obtained by encrypting a first polynomial that corresponds to a first vector, and the second encrypted polynomial is a polynomial obtained by encrypting a second polynomial that corresponds to a second vector. The third polynomial includes a first term that has a coefficient based on an inner product of the first vector and the second vector and a second term other than the first term, in which a coefficient of the second term is masked.

Cryptographic processing method and cryptographic processing device

A method according to an embodiment includes transforming registered data on a user, which is encrypted with an encryption algorithm that enables a calculation of a Hamming distance in an encrypted state, such that a calculation result of a Hamming distance between the registered data and verification data that is encrypted with the algorithm includes a Hamming distance between the verification data and the user's registered data and a Hamming distance between the verification data and a random vector generated from the user's registered data; calculating a Hamming distance between the verification data and the registered data; and determining whether the input verification data is false based on a result of comparison of each of the Hamming distance between the verification data and the user's registered data and the Hamming distance between the verification data and the random vector included in the calculated Hamming distance with a threshold.

Information processing method, computer-readable recording medium, and  information processing apparatus

A memory stores therein a first vector. A processor generates a first encrypted polynomial by encrypting a first polynomial that corresponds to a first binary vector obtained by performing a binary transformation on elements of the first vector. A transmitter transmits to a cryptographic operation device cryptographic information that represents the first encrypted polynomial. The cryptographic operation device multiplies the first encrypted polynomial by a second encrypted polynomial that is generated by encrypting a second polynomial that corresponds to a second binary vector obtained by performing a binary transformation on elements of a second vector, so as to generate a third encrypted polynomial. When assigning 2 to a variable in a prescribed portion of a third polynomial obtained by decrypting the third encrypted polynomial, a result of an operation of the first vector and the second vector is obtained.

An information processing method according to an embodiment causes a computer to execute a process of receiving an input of matching information encrypted with an encryption algorithm allowing a Hamming distance to be calculated with the matching information encrypted. The information processing method also causes the computer to execute a process of calculating a first Hamming distance between the received matching information and registered information that is different from encrypted registered information of a user, the registered information being encrypted with the encryption algorithm, using a processor. The information processing method also causes the computer to execute a process of determining legitimacy of the matching information based on whether the calculated first Hamming distance falls into a distance distribution representing matches with another person that is different from the user, using a processor.

Information processing method, recording medium, and information processing apparatus

An encryption processing method executed by a computer, the method includes converting a first vector using a first polynomial representation to acquire a first polynomial; converting an expression using a second polynomial representation to acquire a second polynomial, the expression being obtained based on a second vector and a random number corresponding to the first vector; converting the random number using at least one of the first polynomial representation and the second polynomial representation to acquire a random number polynomial; encrypting the first polynomial, the second polynomial, and the random polynomial using a homomorphic encryption scheme to acquire the encrypted first polynomial, the encrypted second polynomial, and the encrypted random polynomial; and collating the first vector and the second vector using the encrypted first polynomial, the encrypted second polynomial, and the encrypted random polynomial.

Encryption processing method, encryption processing device, and computer-readable recording medium storing program for encryption processing

A matching method includes: generating a first numerical vector; generating a second numerical vector by squaring each component of the first numerical vector and a third numerical vector by cubing each component of the first numerical vector; generating first to third polynomials by executing polynomial transformation of the first to third numerical vectors; encrypting the first to third polynomials by a homomorphic encryption scheme; executing a predetermined operation while keeping data used in the predetermined operation encrypted, by using fourth to sixth polynomials obtained by the polynomial transformation and the homomorphic encryption of fourth to sixth numerical vectors, wherein the fourth numerical vector is generated by numerically vectorizing second text, the fifth numerical vector is generated by squaring each component of the fourth numerical vector, and the sixth numerical vector is generated by cubing each component of the fourth numerical vector; and decrypting a result of the predetermined operation.

Information processing technique for pattern matching

A non-transitory computer-readable recording medium stores an information processing program that causes a computer to execute a process including, generating feature information based on organism information of a user; calculating a first cryptogram based on a logical operation of the feature information generated and a random number; and encrypting the first cryptogram into a second cryptogram by using a cryptographic algorithm capable of calculating a Hamming distance in an encrypted state.

Information processing apparatus, and information processing method

An encrypted first polynomial that is obtained by encrypting, in a homomorphic encryption method that handles a polynomial processing, a first polynomial, is received from another computer. The first polynomial is represented by using, as coefficients, components of a first binary vector generated from first data in first order that is either ascending order or descending order with respect to degree of the first polynomial. Then, a predetermined processing in an encrypted text space is performed by using the encrypted first polynomial and an encrypted second polynomial that is obtained by encrypting a second polynomial in the homomorphic encryption method. The second polynomial is represented by using, as coefficients, components of a second binary vector generated from second data in second order that is different from the first order with respect to degree of the second polynomial. Then, a result of the predetermined processing is sent back.

Information processing technique for secure pattern matching

A ciphertext processing device acquires a first polynomial into which first text data is converted with a first order and which is encrypted with a first public key and a first square-value polynomial into which square-value vector data of each component of the first text data is converted with the first order and which is encrypted with the first public key. The ciphertext processing device acquires a second polynomial into which second text data is converted with a second order and which is encrypted with the first public key and a second square-value polynomial into which square-value vector data of each component of the second text data is converted with the second order and which is encrypted with the first public key. The ciphertext processing device determines whether the second text data is included in the first text data, using the each polynomial.

Ciphertext processing device, ciphertext processing method, computer-readable recording medium, and information processing device

A secret data matching device includes: a memory; and a processor coupled to the memory. The processor executes a process including: storing a first secret vector obtained by concealing first data and key data based on a first random number and a first linear combination of row vectors of a determination matrix which is different for each system including the secret data matching device and which is generated by attaching a random number vector as a last column to a matrix including diagonal components including a threshold value to determine whether the first data and second data are approximate to each other and a threshold value related to the key data; acquiring a second secret vector obtained by concealing the second data based on a second linear combination of row vectors of the determination matrix and a second random number.

Secret data matching device, secret data matching method, and recording medium

An encryption server receives encrypted data which is encrypted by using a public key of a first user and which is added with auxiliary information calculated using a combination of a secret key and the public key of the first user and data to be encrypted. Then, the encryption server generates re-encrypted data obtained by re-encrypting the encrypted data using the auxiliary information added to the encrypted data, a public key of a second user, and encrypted information related to the secret key of the first user which is encrypted with the public key of the second user.

Growing community of inventors

Kawasaki, Japan

Masaya Yasuda