DMix: decentralized mixer for unlinkability

Abstract

We present a protocol that lets participants operate a decentralized mixer to exchange coins in the Bitcoin blockchain. DMix does not need the election of any leader and respects both the unlinkability and the atomicity properties, so that there is no possibility to correlate addresses or lose funds using the protocol. We leverage the MuSig aggregate signatures. This aggregation scheme is based on the Schnorr signature scheme, a recent proposal for a ECDSA alternative, the current Bitcoin signature scheme. We also present an analysis of the method and mitigation of attacks.