Implementing confidential transactions with lattice techniques

Abstract

The notion of confidential transactions plays a central role in ensuring the confidentiality of transaction amounts in a block-chain-based cryptocurrency. Past researches have confirmed that the access policy of transaction amounts influences the anonymity of a cryptocurrency. Most of the current techniques of confidential transactions are based on the discrete logarithm problem. Because of the threats from quantum algorithms, clients are eager to enjoy security guarantees in a post-quantum scenario. Lattices are an ideal source of hardness, due to its exclusive worst-case to the average-case phenomenon. Nevertheless, the distinctions between the discrete logarithm problem and lattice problems build an obstacle in the way of borrowing the ideas from the former to the latter directly. In this study, inspired by the notion of commitments to polynomials and zero-knowledge arguments of knowledge for the inhomogeneous short integer solution problem, the authors give an approach to implement confidential transactions using lattice techniques.