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.