Abstract: Disclosed is a server device. The server device includes a communication unit configured to perform communication with an external device, a memory configured to store a database including a plurality of keys and data corresponding to each key, and a processor. When a homomorphic encrypted query is received, the processor is configured to acquire an index vector indicating at least one key matching the query from the database, and mask data of each key of the database to the index vector to acquire a data vector including data corresponding to at least one key. The processor is configured to compress each of the index vector and data vector and transmits the compressed index data and data vector to the external device. Accordingly, it is possible to efficiently perform a response to a query.

Abstract: An electronic apparatus is disclosed.

Abstract: A calculation device is disclosed. The calculation device includes: a memory storing at least one instruction and identity information; and a processor performing the at least one instruction, wherein the processor may randomly sample small elements, generate a function-processed output value by function-processing the stored identity information, and generate an encrypted text for a message by using a master public key computed using a ring having a dimension (d) represented by a power of 2 and an integer multiplication of 3 or more, the sampled small elements and the function-processed output value.

Abstract: Disclosed is an electronic device. The device includes: a communicator; a memory for storing information on a plurality of references for diagnosing a password; and a processor, wherein the processor is configured to acquire a calculation result in an encrypted form by performing a calculation based on a calculation key for each of a homomorphic ciphertext and the plurality of references, and transmit the calculation result to at least one external device through the communicator, in case of receiving the homomorphic ciphertext, in which the password is homomorphically encrypted, and data for the calculation key from the at least one external device through the communicator. Accordingly, the device can effectively diagnose whether the password is usable.

Abstract: A method for processing homomorphic ciphertexts includes: receiving an input of an instruction for sorting regarding a plurality of homomorphic ciphertexts; sorting the plurality of homomorphic ciphertexts by using a sorter which can sort 3 more homomorphic ciphertexts in a single stage; and outputting the sorting result. The sorter performs sorting by using a comparison function that selectively outputs a bigger value or a smaller value between two input values.

Abstract: Disclosed is a calculation device. The present calculation device includes: a memory for storing a plurality of homomorphic ciphertexts for an approximate message including an error; and a processor for sorting the plurality of homomorphic ciphertexts by using a 5-way sorter which can sort five homomorphic ciphertexts in a single stage.

Abstract: Disclosed is an electronic device including: a memory storing a lookup table including identification information and data matched to the identification information; an interface; and a processor configured to search the data matched to the identification information corresponding to search information by generating a position identification vector including the number of elements corresponding to the number of the lookup table, and repeatedly performing an operation of updating the position identification vector based on a comparison calculation result based on the search information and each segmented table part while segmenting the lookup table into a plurality of parts, in case of receiving the search information through the interface. Accordingly, the device may perform effective data search on the table including a homomorphically encrypted message.

Abstract: Disclosed is an electronic device which distributes secret keys by using a t-out-of-N secret sharing scheme. The electronic device includes: a communication device; a memory storing the secret key; and a processor configured to generate a plurality of secret shares corresponding to a level of 1 by segmenting the secret key corresponding to a level of zero based on a predetermined secret sharing scheme, generate a plurality of secret shares corresponding to a level of L by repeatedly performing a process of generating a plurality of secret shares corresponding to a next level by segmenting the plurality of secret shares each corresponding to the respective levels ranging from the level of 1 based on the predetermined secret sharing scheme, and transmit the plurality of secret shares corresponding to the level of L to N electronic devices through the communication device.

Abstract: Disclosed are an electronic apparatus and a control method thereof. According to the present disclosure, an electronic apparatus with N-bit hardware architecture includes a memory configured to store a scaling factor, and a processor configured to obtain a homomorphic encrypted message with an M*N-bit word size, and perform an operation on the homomorphic encrypted message using the scaling factor. In this case, the M is an integer of 2 or more, and the scaling factor is composed of M prime numbers.

Abstract: Disclosed is an electronic device. The device includes: a memory storing a tree-structured decision-making model for making a decision; an interface for receiving an input value; and a processor configured to acquire a result value of a tree structure that corresponds to the input value by performing a reduction operation of reducing the tree structure at least once, wherein the reduction operation includes a comparison calculation of comparing the input value with a value of one of nodes included in the tree structure is performed, and a comparison calculation result is added to nodes at corresponding positions in a plurality of lower tree structures branching from the node, and then the nodes are combined with each other.

Abstract: An encoding method includes: receiving a plurality of messages; encoding the plurality of messages into a polynomial defined by multivariates; and encrypting the polynomial defined by the multivariates to generate a homomorphic ciphertext. The plurality of messages may be multidimensionally packed by using multivariates, and thus, an operation may be performed with low complexity in the process of matrix multiplication for ciphertexts packed with the multivariates.

Abstract: Disclosed are an electronic device and a controlling method.

Abstract: An operation device is disclosed. The operation device includes a memory storing at least one instruction, and a processor executing the at least one instruction, wherein the processor is configured to, by executing the at least one instruction, perform decryption for a homomorphic encryption by using information for a secret key, and the secret key is expressed as a polynomial having a plurality of terms, and the information for the secret key includes information on degrees and coefficients of the plurality of respective terms.

Abstract: The electronic device includes: a communicator communicating with a plurality of external devices each generating an encryption key; a memory; and a processor, wherein the processor stores a plurality of encrypted messages in the memory when receiving the plurality of encrypted messages each encrypted with the encryption key by the plurality of external devices through the communicator, performs a key switching operation using a switching key for the plurality of encrypted messages to change each of the plurality of encrypted messages to the encrypted message encrypted with a common key, and evaluates the changed plurality of encrypted messages by using at least one evaluation key.

Abstract: A calculation device is disclosed. The calculation device includes: a memory storing at least one instruction and identity information; and a processor performing the at least one instruction, wherein the processor may randomly sample small elements, generate a function-processed output value by function-processing the stored identity information, and generate an encrypted text for a message by using a master public key computed using a ring having a dimension (d) represented by a power of 2 and an integer multiplication of 3 or more, the sampled small elements and the function-processed output value.

Abstract: An electronic device is disclosed.

Abstract: Disclosed is an electronic device. The electronic device includes a communicator, a memory configured to store data for generating a key, and a processor. The processor may generate a secret key by randomly combining values within a preset range based on the data stored in the memory, generate a public key using the secret key and an error, and store the secret key and the public key in the memory, transmit the public key to an external device using the communicator, and a sum of the number of remaining values other than zero (0), among the values within the preset range, may correspond to a Hamming weight. Accordingly, encryption and decryption may be performed efficiently.

Abstract: Provided are an electronic apparatus and a method for verifying encrypted data. The verification method of the electronic apparatus includes transmitting encrypted quotient polynomial rings to an external device, receiving, from the external device, a result value calculated through an operation process for at least one layer on the basis of the transmitted encrypted polynomial rings, transmitting a random value to the external device, and receiving claim data obtained by performing the operation process in a reverse order on the basis of the random value from the external device, and verifying the received result value on the basis of a value of the quotient polynomial rings corresponding to the random value and the received claim data.

Abstract: A mobile device is disclosed. The device includes a communicator, a GPS unit for calculating location information, a memory, a display, and a processor, and the processor is configured to generate movement path information of the mobile device by performing homomorphic encryption of a plurality of pieces of location information stored in the memory, transmit the movement path information to a server apparatus through the communicator, based on operation result data obtained by operating based on the movement path information and comparison target path information being transmitted from the server apparatus, decrypt the operation result data, and output a message notifying whether a route overlaps the comparison target path information based on a decrypted result through the display. Therefore, the route overlap is rapidly and accurately confirmed without invasion of privacy.

Abstract: In a method of generating a secret key according to an embodiment, a share of each of a user and a plurality of other users for a secret key of the user are generated, the share of each of the plurality of other users is provided to a user terminal of each of the plurality of other users, a share of the user for a secret key of each of the plurality of other users is received from the user terminal of each of the plurality of other users, and a new secret key of the user is generated using the share of the user for the secret key of the user and the shares of the user for the secret key of each of the plurality of other users.