CRYPTO LAB INC.

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.

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.

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.

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.

An electronic apparatus is disclosed. The electronic apparatus includes a memory configured to store a homomorphic ciphertext including a tag and a program operating in the electronic apparatus, a user interface, and a processor, and the tag includes type information for original data of the homomorphic ciphertext, and is set, based on computation for the homomorphic ciphertext being performed, such that the tag included in the homomorphic ciphertext used in the computation is included in even a computation result value generated by the computation being performed, and the processor is configured to generate, based on receiving a computation request for the homomorphic ciphertext from the program, a computation result value by performing computation for the homomorphic ciphertext, check the type information for the original data of the homomorphic ciphertext used in the computation based on the tag included in the computation result value, perform decryption of the computation result value, control the user interface to display the checked type information for the original data and the decrypted computation result value, and provide, based on receiving a command to provide data through the user interface, the decrypted computation result value to the program.

An electronic device is disclosed. The electronic device comprises: a memory for storing at least one instruction; and a processor for executing at least one instruction, wherein the processor executes the at least one instruction so as to, when an operation command for a homomorphic ciphertext is input, obtain an operation result by using a plaintext operation corresponding to the operation command and a plaintext corresponding to the homomorphic ciphertext, and output the obtained operation result in a manner corresponding to the operation command.

An electronic device is disclosed. The electronic device includes a memory configured to store at least one instruction, and store homomorphic ciphertexts storing a plurality of variable data in an encrypted state in plurality, and a processor configured to execute at least one instruction, and the processor is configured to generate, by executing the at least one instruction, number data corresponding to a variable combination by using a bin mask having different variable data classified for each of the homomorphic ciphertexts based on an operation instruction on the plurality of homomorphic ciphertexts being received.

An electronic device is disclosed. The electronic device comprises: a memory for storing at least one instruction; and a processor for executing at least one instruction, wherein the processor executes the at least one instruction so as to, when an operation command for a homomorphic ciphertext is input, obtain an operation result by using a plaintext operation corresponding to the operation command and a plaintext corresponding to the homomorphic ciphertext, and output the obtained operation result in a manner corresponding to the operation command.

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.

A data sharing method of a user device is provided. The data sharing method includes receiving, from a server device storing information, a private key corresponding to the information, performing a homomorphic encryption of the private key by a homomorphic encryption key provided from the server device, and generating a switch key, and uploading the switch key to a blockchain system. Accordingly, a more effective and clear data sharing is provided.