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.