Fujitsu Corporation

Takeshi Shimoyama

Masaya Yasuda

Jun Kogure

Arnab Roy

Hart Montgomery

Masahiko Takenaka

Hiroshi Tsuda

Avradip Mandal

Jun Yajima

Yoshinori Yaginuma

Toshiya Shimizu

Ryota Kamakari

Toshiyuki Ishiguro

Kouhei Shigeta

Ryuichi Ohori

Yusuke Sakai

Yasuo Noguchi

Kazuyoshi Furukawa

Naoya Torii

Hitoshi Yanami

Koichi Ito

Goichiro Hanaoka

Kazumasa Omote

Seonghan Shin

Kazuhiro Yokoyama

Jumpei Yamaguchi

An encryption processing system includes: a first device; second devices; and a third device, wherein the first device generates synthesis keys by selecting public keys of the second devices; generates an intermediate text from confidential texts generated by encrypting secret information by using public keys of the second devices having decryption authority; generates ciphertexts by further encrypting the intermediate text using the synthesis keys; and makes public the ciphertexts, each of the second devices verifies validity of the ciphertexts; generates decryption key fragments by using an own private key; and makes public the decryption key fragments, the third device verifies validity of the decryption key fragments; generates a decryption key by combining decryption key fragments; generates the Intermediate text by decrypting one of the ciphertexts; and makes public the intermediate text, and the second device decrypts the intermediate text using the own private key; and restores the secret information.

Encryption processing system and encryption processing method

A method may include obtaining a set of multivariate quadratic polynomials associated with a multivariate quadratic problem and generating an Ising Model connection weight matrix 'W' and an Ising Model bias vector 'b' based on the multivariate quadratic polynomials. The method may also include providing the matrix &#x201c;W&#x201d; and the vector &#x201c;b&#x201d; to an annealing system configured to solve problems written according to the Ising Model and obtaining an output from the annealing system that represents a set of integers. The method may also include using the set of integers as a solution to the multivariate quadratic problem.

Solving multivariate quadratic problems using digital or quantum annealing

A key generation device includes a generation circuit, a concealment processing unit, and a cryptography processing unit. The generation circuit generates a value dependent on hardware. When acquiring a concealed cryptographic key, the concealment processing unit generates first data by performing a mask process to the concealed cryptographic key by using the value generated by the generation circuit, generates second data by decoding the first data by a first error correction decoding method, and generates a cryptographic key by decoding the second data by a second error correction decoding method. When acquiring the concealed cryptographic key and a plain text or an encrypted text, the cryptography processing unit acquires the cryptographic key corresponding to the concealed cryptographic key from the concealment processing unit, and encrypts the plain text or decrypts the encrypted text by using the cryptographic key.

Key generation device and key generation method

A mask is selected amongst a plurality of masks. A first masked random number is generated by converting a first random number using the selected mask, and a first key is generated from the first masked random number and a first biometric code generated from biometric information. In addition, mask information indicating the selected mask is stored. A second masked random number is generated by converting a second random number using the selected mask or a different mask having a predetermined relationship with the selected mask, and a second key is generated from the second masked random number and a second biometric code. A ciphertext is generated using one of the first key and the second key and an error-correction encoding method.

Method and apparatus for cryptographic data processing

A method of equality verification using relational encryption including receiving a relational key that includes a first relational key component and a registration ciphertext that includes an encryption of a first plaintext data set. The method includes storing the registration ciphertext without decrypting the registration ciphertext. After the storing of the registration ciphertext, the method includes receiving an authentication request and communicating a safeguard data set that includes a random challenge in response to the authentication request. The method includes receiving an encrypted response that is generated based on the safeguard data set and a second plaintext data set. The method includes verifying a relationship between the encrypted response and the registration ciphertext using the relational key without decrypting the encrypted response and without decrypting the registration ciphertext. The relationship indicates that equality exists between the first and the second plaintext data sets.

Relational encryption for password verification

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

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

A method includes receiving biometric data, the biometric data non-uniformly distributed and processing the biometric data to a level of randomness as a plaintext vector, the level of randomness associated with a security level. The method also includes encrypting the plaintext vector using a relational linearity encryption scheme to generate a linearity ciphertext representative of the plaintext vector, encrypting the plaintext vector using a relational proximity encryption scheme to generate a proximity ciphertext representative of the plaintext vector, and communicating the linearity ciphertext and the proximity ciphertext to an authentication server. The method further includes receiving from the authentication server an authentication signal for the security level indicative of a linearity relationship between the linearity ciphertext and a registration linearity ciphertext discovered using a relational linearity key and of a proximity relationship between the proximity ciphertext and a registration proximity ciphertext detected using a relational proximity key.

Relational encryption

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

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.

Encryption device, encryption method, and information processing device

A device that uses homomorphic encryption is disclosed. The device includes a public key data generator configured to generate public key data, and a secret key data generator configured to generate secret key data that includes, as a secret key, an integer that is an element of a matrix obtained as a product of the first public key matrix element and an inverse matrix of the secret key matrix and that is not a multiple of the plain text space size.

Cryptography processing device and cryptography processing method

A device that uses homomorphic encryption is disclosed. The device obtains a first encrypted polynomial, a second encrypted polynomial, a first encrypted weight, and a second encrypted weight by respectively encrypting a first polynomial, a second polynomial, a first weight, and a second weight by using a homomorphic encryption scheme, and obtains an encrypted secure distance corresponding to encryption of a secure distance.

Growing community of inventors

Shinagawa, Japan

Takeshi Shimoyama