Electronic device for user authentication, server, and control method therefor

An electronic device comprising:

• storage configured to store tag information, the tag information comprising first tag information for communication to a server for user registration and second tag information for communication to the server for user authentication;
• a communicator comprising a communication circuit;
• a sensor;
• and
• at least one processor configured to:
• obtain a first biometric code string from biometric data sensed by the sensor,
• obtain a first cryptogram by encrypting the first biometric code string and the second tag information,
• transmit the first cryptogram, a first masking code, and a first masking encryption code obtained by encrypting the first masking code to the server via the communicator,
• receive a second cryptogram including third tag information, via the communicator,
• decrypt the second cryptogram,
• identify whether the third tag information corresponds to a first distance value corresponding to a difference between the first tag information and the second tag information,
• based on identifying that the third tag information corresponds to the first distance value between the first tag information and the second tag information,
• obtain a value for authentication by adding a second distance value to a second masking code, and
• transmit the obtained authentication value to the server via the communicator for user authentication,
• wherein the second distance value is a distance value between the first biometric code string and a second biometric code string stored in the server in advance, and
• wherein the second masking code is a code obtained by the server based on the first masking code.