Electronic device and server device responding to encrypted query and methods thereof

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.