Möbius: Trustless Tumbling for Transaction Privacy

Authors: Sarah Meiklejohn (University College London), Rebekah Mercer (Aarhus University)

Volume: 2018
Issue: 2
Pages: 105–121
DOI: https://doi.org/10.1515/popets-2018-0015

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Abstract: Cryptocurrencies allow users to securely transfer money without relying on a trusted intermediary, and the transparency of their underlying ledgers also enables public verifiability. This openness, however, comes at a cost to privacy, as even though the pseudonyms users go by are not linked to their realworld identities, all movement of money among these pseudonyms is traceable. In this paper, we present Möbius, an Ethereum-based tumbler or mixing service. Möbius achieves strong notions of anonymity, as even malicious senders cannot identify which pseudonyms belong to the recipients to whom they sent money, and is able to resist denial-of-service attacks. It also achieves a much lower off-chain communication complexity than all existing tumblers, with senders and recipients needing to send only two initial messages in order to engage in an arbitrary number of transactions.

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