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: An electronic apparatus which generates a homomorphic encrypted message by homomorphically encrypting voting analysis data includes: a processor configured to execute the at least one instruction, wherein the processor is configured to generate a vote-homomorphic encrypted message including the voting data of the voter for a first candidate and a second candidate by using a first candidate mask corresponding to the first candidate in a first election and a second candidate mask corresponding to the second candidate in a second election, for a first election-homomorphic encrypted message acquired by homomorphically encrypting the voting data of the voter in the first election and a second election-homomorphic encrypted message acquired by homomorphically encrypting the voting data in the second election, and generate a result-homomorphic encrypted message including the number of voters who select the first candidate and the second candidate by using the generated vote-homomorphic encrypted message.

Abstract: Disclosed is a data management method and apparatus. The data management method includes: obtaining a hash value of a key by using a predetermined hash function for each of a plurality of data in which the key matches a data value, sorting the plurality of data in which the key is changed to the hash value of the key based on the obtained hash value, classifying the plurality of sorted data into a plurality of groups according to a predetermined criterion; encoding the plurality of data classified into the plurality of groups, and generating a lookup table based on a predetermined hash value included in each of the plurality of classified groups.

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 apparatus. The electronic apparatus includes a memory configured to store at least one instruction and store a plurality of categorical data whose values are expressed as a plurality of classes for one category, and a processor configured to execute the at least one instruction to generate the plurality of categorical data into one homomorphic encrypted message, in which the processor is configured to generate a categorical column in which homomorphically encrypted data for each of the plurality of categorical data is located in a plurality of slots, generate mask columns corresponding to each of the plurality of classes to correspond to the number of the plurality of classes, and generate the homomorphic encrypted message by combining the categorical column and the plurality of mask columns.

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

Abstract: Disclosed is an operation device. The operation device includes a memory storing at least one instruction; and a processor configured to execute the at least one instruction, and the processor, by executing the at least one instruction, may perform encoding or decoding for an approximate homomorphic ciphertext using a predetermined matrix having only a half of an element of a matrix corresponding to a canonical embedding function.

Abstract: An electronic apparatus for generating a homomorphic encrypted message includes: a processor configured to generate a mask homomorphic encrypted message by homomorphically comparing the homomorphic encrypted message with the index data in case that a calculation command of the predetermined function for the homomorphic encrypted message is input, generate an intermediate homomorphic encrypted message by homomorphically multiplying the generated mask homomorphic encrypted message by the function result data, generate a function-result encrypted message for the homomorphic encrypted message by computing sum of values in a plurality of slots of the intermediate homomorphic encrypted message.

Abstract: Disclosed is an electronic apparatus. The electronic apparatus includes: a memory storing a plurality of homomorphic encryptions and lookup table information; a communication apparatus configured to perform communication with an external apparatus; and a processor configured to retrieve the homomorphic encryption in response to a requested query, wherein the lookup table information stores data acquired by homomorphically encrypting keyword information and index information that respectively correspond to the plurality of homomorphic encryptions, and the processor is configured to retrieve the homomorphically encrypted index information by using received query information and the lookup table information in case of receiving the query information from the external apparatus, and control the communication apparatus to transmit the retrieved index homomorphic encryption to the electronic apparatus.

Abstract: Disclosed is a server device. The device includes: a communicator; a memory; and a processor. Here, a processor is configured to transmit user interface (UI) data including a plurality of questions to an external device through the communicator, based on the plurality of answers corresponding to the plurality of questions are received from the external device store a plurality of answers in the memory, generate a secret sentence used for generating a password based on the plurality of answers, and transmit the generated secret sentence to the external device through the communicator. The plurality of answers include a homomorphic ciphertext that is homomorphically encrypted by the external device. Accordingly, the password may be generated while maintaining its security.

Abstract: An operation apparatus performing matrix multiplication of a homomorphic encryption is disclosed. The operation apparatus includes a memory configured to store at least one instruction and a plurality of homomorphic ciphertexts, and a processor configured to execute the at least one instruction. The processor is configured to generate first matrix data having a row of a predetermined size and a column of a predetermined size using the plurality of homomorphic ciphertexts, generate a plurality of third matrix data having a row which is the size of the predetermined column and the column of the predetermined size by arranging second matrix data having a row which is 1/n size of the predetermined column and the column of the predetermined size sequentially n-times, and perform a homomorphic multiplication operation between same rows and same columns using the first matrix data and the generated respective third matrix data.

Abstract: Disclosed is a server. The server includes a camera, a memory configured to store an encrypted database generated based on a plurality of feature vectors corresponding to a plurality of users, and a processor configured to acquire an image obtained by capturing a target user's face using the camera and transform a feature vector acquired from the image based on transformation and identify the target user based on the transformed feature vector and the encrypted database. The encrypted database is generated by transforming the plurality of feature vectors based on the transformation and homomorphically encrypting the plurality of transformed feature vectors. The transformation transforms components of the feature vectors into 1, ?1, or 0 depending on magnitudes and signs of the components of the feature vectors.

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: 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: Disclosed are an electronic device and a control method thereof.

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: A text search method is disclosed. The text search method includes, based on a query including a text being input, computing a vector value having a preset size by using a preset encoding algorithm, the vector value corresponding to the text, generating a query ciphertext by homomorphic encryption for the computed vector value, transmitting the generated query ciphertext to a server, receiving a calculation result ciphertext having similarity information with the query for each of a plurality of indexes, determining an index having a preset similarity by restoring the calculation result ciphertext, and receiving information corresponding to the index by transmitting the determined index to the server.

Abstract: Disclosed is a method of processing an encrypted message. The method of processing an encrypted message includes checking exponential data and mantissa data for numerical data, performing homomorphic encryption on the mantissa data, and merging the encrypted mantissa data and the exponential data to generate a homomorphic encrypted message.

Abstract: An electronic apparatus is disclosed.

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.