INFORMATION-THEORETIC SECURE USER AUTHENTICATION VIA SECRET SHARING COMPUTATION

Abstract

When using an insecure communication channel, the initial step involves authenticating the user (verifying the other party) to ensure the legitimacy of the communication partner, followed by encrypted communication. With the advancement of quantum computers, many conventional cryptographic techniques are at risk of being deciphered. While postquantum cryptographic approaches are under development, they often demand substantial computational resources, making them difficult to implement in resourceconstrained environments such as the Internet of Things (IoT). This study proposes a user authentication and secure communication system that guarantees information-theoretic security by leveraging secure computation based on a computationally lightweight (k, n)-threshold secret sharing scheme. The proposed authentication approach utilizes constantly changing information to prevent replay attacks and enhance security. It is further demonstrated that secure communication with information-theoretic guarantees can be achieved without the need to distribute a large volume of true random numbers, relying instead on secret sharing-based secure computation. The proposed methods are particularly suitable for IoT applications due to their minimal processing overhead and efficient performance.