Secure User Authentication With Information Theoretic Security Using Secret Sharing-Based Secure Computation

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. Public-key encryption-based digital signatures are widely utilized for user authentication; however, they is highly likely that it will be deciphered with the development of quantum computers. Studies are also being conducted on post-quantum cryptography, although it requires significant computational resources and is challenging to implement in Internet of Things (IoT) devices. Consequently, this study suggests the implementation of user authentication and secure communication that guarantees information-theoretic security through the use of a secure computation based on a computationally light ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k, n</i> ) threshold secret sharing scheme. In this study, we first propose a user authentication system with information-theoretical security utilizing constantly changing information. Subsequently, we demonstrate that secure communication with information-theoretic security can be achieved without the need to distribute a substantial amount of true random numbers, by employing a secure computation based on ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k, n</i> ) threshold secret sharing. Our proposed methods are suitable for implementation in an IoT environment, as they require minimal processing overhead. We also demonstrate the practical application of the proposed methods through implementation using C++. For example, the claimant’s average execution time is less than 0.1 [ms], and the proposed methods are very efficient.