Abstract: An example embodiment provides a calculating method using a zero-knowledge proof-friendly one-way function, performed by a computing device, the calculating method including: calculating a first intermediate bit stream by inputting an input bit stream of a one-way function to an augmented matrix, calculating a second intermediate bit stream by dividing the first intermediate bit stream into a predetermined number of bit streams and inputting each of the predetermined number of divided bit streams to a substitution-box (S-box), and outputting an output bit stream of the one-way function by inputting the second intermediate bit stream to a reduced matrix.

Abstract: A method of generating a cryptographic algorithm according to one embodiment of the present disclosure includes generating one or more key tables on the basis of a seed value; generating a first transformation function that converts an input bit string, which is input to one of input branches of a Feistel structure, into a first random bit string having a length that extends beyond a length of the input bit string; generating a second transformation function that converts a second random bit string generated by referencing the one or more key tables into a third random bit string having a length that is the same as the length of the input bit string; and generating a block cryptographic algorithm of a Feistel structure which includes a round function to which the one or more key tables, the first transformation function, and the second transformation function are applied.

Abstract: A method of generating a cryptographic algorithm includes generating at least one key table on the basis of a seed value; generating, by using a round tweak bit string and an input bit string that is input to one of input branches of a Feistel structure, a first transformation function converting the input bit string into a first random bit string having a length that extends beyond a length of the input bit string, generating a second transformation function converting a second random bit string generated by referencing the one or more key tables into a third random bit string having a length that is the same as the length of the input bit string, and generating a block cryptographic algorithm of a Feistel structure which includes a round function to which the one or more key tables, the first transformation function, and the second transformation function are applied.

Abstract: A method for encryption according to an embodiment includes generating a ciphertext for a secret key that is an integer vector by using an integer-based first homomorphic encryption algorithm, generating a key stream that is the integer vector from a nonce and the secret key by using a key stream generator, encoding the key stream by using a message encoding function of the first homomorphic encryption algorithm, encoding a message that is a real vector by using a message encoding function of a real number-based second homomorphic encryption algorithm, generating a ciphertext for the message by using a result of the encoding of the key stream and a result of the encoding of the message, and transmitting the nonce, the ciphertext for the secret key, and the ciphertext for the message to an apparatus for converting a ciphertext.

Abstract: A method according to one embodiment includes generating one or more key tables based on a first seed value; generating one or more secret values from a tweak value based on the one or more key tables; and performing encryption or decryption using the one or more secret values. An apparatus according to one embodiment includes a key table generator configured to generate one or more key tables based on a first seed value, a secret value generator configured to generate one or more secret values from a tweak value based on the one or more key tables, and an encryptor/decryptor configured to perform encryption or decryption using the one or more secret values.

Abstract: A method for data analysis according to an embodiment includes acquiring, from a client device, a ciphertext for a precomputation result generated by applying some of a plurality of operations for performing an analysis algorithm based on target data to the target data, and generating an encrypted computation result for remaining operations of the plurality of operations by using the ciphertext.

Abstract: A method for performing a matrix multiplication operation being secure against side-channel attacks according to one embodiment, which is performed by a computing device comprising one or more processors and a memory storing one or more programs to be executed by the one or more processors, includes shuffling an order of execution of multiplication operations between elements of a first matrix and elements of a second matrix for a matrix multiplication operation between the first matrix and the second matrix; and performing the matrix multiplication operation based on the shuffled order of execution.

Abstract: A method for generating a key stream according to an embodiment includes generating r round keys that are each N-dimensional integer vectors including elements of an integer set defined based on a prime number t, based on a random bit string, an encryption counter, and a secret key that is an N-dimensional integer vector consisting of elements of the integer set , generating a first round output vector x1 by performing a modular addition operation on an initial vector and a first round key RK1 of the r round keys with the prime number t as a modulus, and generating a key stream that is an N-dimensional integer vector consisting of elements of the integer set from the first round output vector x1 by using a second to r-th round keys of the r round keys, and one or more first round functions and a second round function.

Abstract: An apparatus for encryption according to an embodiment of the present disclosure comprises a classifier configured to classify each data included in an original data set into one of encryption target data and non-encryption target data on the basis of at least one of determination on whether or not an operation to be applied to each data included in the original data set for an analysis of the original data set is a preset operation and determination on whether or not each data included in the original data set is sensitive information; and an encryptor configured to encrypt the encryption target data among the data included in the original data set using a homomorphic encryption algorithm.

Abstract: A method for performing an operation according to an embodiment includes assigning an error value to encrypted data; and performing a homomorphic operation for an approximation function, which is obtained by approximating a target function, by using, as an input value, the encrypted data to which the error value is assigned.

Abstract: An apparatus for set intersection operation according to an embodiment includes a ciphertext acquisition unit configured to acquire a ciphertext for a first vector corresponding to a first subset of a universal set including a plurality of elements from an encryption apparatus, a transform unit configured to generate a second vector corresponding to a second subset of the universal set, a computation unit configured to generate a ciphertext for a third vector corresponding to an intersection of the first subset and the second subset, based on the ciphertext for the first vector and the second vector, and a ciphertext providing unit configured to provides the ciphertext for the third vector to the encryption apparatus.

Abstract: A method for performing an operation according to one embodiment includes performing a homomorphic operation using one or more ciphertexts that are homomorphically encrypted based on an encryption key, determining a count value for a ciphertext generated through the homomorphic operation based on count values for each of the one or more ciphertexts, requesting a key management apparatus, which holds the encryption key and a decryption key corresponding to the encryption key, to re-encrypt the generated ciphertext based on the determined count value, acquiring, from the key management apparatus, a ciphertext generated by re-encrypting the generated ciphertext through decryption based on the decryption key and encryption based on the encryption key; and determining a count value for the acquired ciphertext to be a preset initial value.

Abstract: A method for data analysis according to an embodiment includes acquiring, from a client device, a ciphertext for a precomputation result generated by applying some of a plurality of operations for performing an analysis algorithm based on target data to the target data, and generating an encrypted computation result for remaining operations of the plurality of operations by using the ciphertext.

Abstract: A method for encryption according to an embodiment includes generating a ciphertext for a secret key that is an integer vector by using an integer-based first homomorphic encryption algorithm, generating a key stream that is the integer vector from a nonce and the secret key by using a key stream generator, encoding the key stream by using a message encoding function of the first homomorphic encryption algorithm, encoding a message that is a real vector by using a message encoding function of a real number-based second homomorphic encryption algorithm, generating a ciphertext for the message by using a result of the encoding of the key stream and a result of the encoding of the message, and transmitting the nonce, the ciphertext for the secret key, and the ciphertext for the message to an apparatus for converting a ciphertext.

Abstract: A method for performing an operation according to one embodiment includes performing a homomorphic operation using one or more ciphertexts that are homomorphically encrypted based on an encryption key, determining a count value for a ciphertext generated through the homomorphic operation based on count values for each of the one or more ciphertexts, requesting a key management apparatus, which holds the encryption key and a decryption key corresponding to the encryption key, to re-encrypt the generated ciphertext based on the determined count value, acquiring, from the key management apparatus, a ciphertext generated by re-encrypting the generated ciphertext through decryption based on the decryption key and encryption based on the encryption key; and determining a count value for the acquired ciphertext to be a preset initial value.

Abstract: An apparatus and method for performing an operation which are secure against side-channel attack are provided. According to one embodiment of the present disclosure, the apparatus includes a first outputter configured to output a first output value corresponding to a seed value using a first parameter candidate value set, a second outputter configured to output a second output value using a second parameter candidate value set wherein the second output value corresponds to the seed value and is capable of being generated using the first output value, a third outputter configured to output a third output value using the seed value and the first output value, and a fourth outputter configured to output a fourth output value using the second output value and the third output value, wherein the fourth output value is capable of being generated using the seed value.

Abstract: A method of provisioning key information and a device using the method are provided. The method of provisioning key information according to one embodiment of the present disclosure includes generating key information for encryption and decryption from seed information using a key information generation algorithm and deleting code that corresponds to the key information generation algorithm from the device based on the generation of the key information.

Abstract: A method for performing an operation according to an embodiment includes assigning an error value to encrypted data; and performing a homomorphic operation for an approximation function, which is obtained by approximating a target function, by using, as an input value, the encrypted data to which the error value is assigned.

Abstract: An apparatus for set intersection operation according to an embodiment includes a ciphertext acquisition unit configured to acquire a ciphertext for a first vector corresponding to a first subset of a universal set including a plurality of elements from an encryption apparatus, a transform unit configured to generate a second vector corresponding to a second subset of the universal set, a computation unit configured to generate a ciphertext for a third vector corresponding to an intersection of the first subset and the second subset, based on the ciphertext for the first vector and the second vector, and a ciphertext providing unit configured to provides the ciphertext for the third vector to the encryption apparatus.

Abstract: A system and method for communication between devices are provided. According to the embodiments of the present disclosure, it is possible to easily authenticate a counterpart device using a one-time key HN(T) for a D2D communication between a first device and a second device, without using a separate secure channel (e.g., secure sockets layer (SSL), transport layer security (TLS), or the like) in an environment where it is difficult to synchronize the first device with the second device without intervention of a server.