Oscausi - Practical Private Electronic Cash from Lelantus and MimbleWimble

Lasse Herskind, Panagiota Katsikouli, and Nicola Dragoni

DTU Compute, Lyngby, Denmark

s153746@student.dtu.dk, {panka, ndra}@dtu.dk

Abstract

After challenging the privacy guarantees of Bitcoin, a lot of alternatives have been proposed to enhance the privacy-properties of Bitcoin. While Zcash (one of such alternatives) significantly improves the privacy of Bitcoin, its two-coin design with a public base-coin permits critical attacks to happen. In this paper we propose Oscausi, an anonymous payment system that supports practical confidential and anonymous transactions without a public basecoin nor a trusted setup. The scheme is inspired by the Lelantus and MimbleWimble schemes, joining the ideas into one system, with a confidential basecoin and privacy through a shielded pool. Our proposal supports non-interactive transaction aggregation across shielded and unshielded transactions. The scheme is built upon well-known cryptography, is easily auditable and requires no trusted setup.

Keywords: Anonymity, Confidentiality, Cryptocurrencies, Electronic Cash, Privacy, Zero-Knowledge

+: Corresponding author: Panagiota Katsikouli
Department of Computer Science and Mathematics, Technical University of Denmark, 115/322, 2800 Kongens Lyngby, Denmark

Journal of Internet Services and Information Security (JISIS), 10(2): 16-34, May 2020

DOI: 10.22667/JISIS.2020.05.31.016 [pdf]