Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A proximity determination method includes: collecting a first concealed vector based on a linear combination of a row vector of a key matrix, first numerical information, and a first random number, the key matrix being generated by adding a random number vector as a last column to a matrix in which a threshold for determining a proximity range is a diagonal element; collecting a second concealed vector based on the linear combination, second numerical information, and a second random number; calculating a remainder vector, the remainder vector being a remainder obtained from a difference between the collected first concealed vector and the second concealed vector when the key matrix is used as a modulus; and determining whether the first numerical information and the second numerical information belong to the proximity range, based on the calculated remainder vector.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A decryption method includes receiving an input of an n-dimensional vector whose elements other than a first element are all zero, or of the first element. The vector is a ciphertext obtained by encrypting a plaintext being an integer not less than 0 and less than s with a public key, or by performing an operation on a plurality of ciphertexts without decrypting them. The public key is associated with an n×n invertible matrix V defined as a secret key of homomorphic cryptography by using n integers, and is a matrix B being an Hermite normal form of V. The decryption method also includes: acquiring an element w which is coprime to s and which is one of elements of a matrix W=dV?1 defined by a determinant d of B and V?1; acquiring w?1 modulo s; calculating b=[c×w]d×w?1 mod s; and outputting b as a plaintext.

Abstract: 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.

Abstract: 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.

Abstract: A proximity determination method includes: collecting a first concealed vector based on a linear combination of a row vector of a key matrix, first numerical information, and a first random number, the key matrix being generated by adding a random number vector as a last column to a matrix in which a threshold for determining a proximity range is a diagonal element; collecting a second concealed vector based on the linear combination, second numerical information, and a second random number; calculating a remainder vector, the remainder vector being a remainder obtained from a difference between the collected first concealed vector and the second concealed vector when the key matrix is used as a modulus; and determining whether the first numerical information and the second numerical information belong to the proximity range, based on the calculated remainder vector.

Abstract: A data processing apparatus includes an address bus, a scramble unit, and a data bus. The address bus outputs address data to be given to a memory apparatus. The scramble unit scrambles write-in data into a storage position in the memory apparatus identified by the address data to obtain confidential data. The data bus outputs the confidential data. The scramble unit includes a first scrambler, a first converter and a second scrambler. The first scrambler XORs first mask data corresponding to the address data and the write-in data for each bit and makes it first scrambled data. The first converter performs one-to-one substitution conversion of the first scrambled data. The second scrambler XORs second mask data corresponding to the address data and data after the conversion of the first scrambled data by the first converter and outputs obtained second scrambled data as the confidential data.