Title:             Quisquis: A New Design for Anonymous Cryptocurrencies
Authors:           Prastudy Fauzi; Claudio Orlandi; Sarah Meiklejohn; Rebekah Mercer
Key words:         cryptographic protocols, anonymity, cryptocurrencies, privacy-preserving systems

Abstract:
Despite their usage of pseudonyms rather than persistent identifiers, most
existing cryptocurrencies do not provide users with any meaningful levels of
privacy. This has prompted the creation of privacy-enhanced cryptocurrencies
such as Monero and Zcash, which are specifically designed to counteract the
tracking analysis possible in currencies like Bitcoin. These cryptocurrencies,
however, also suffer from some drawbacks: in both Monero and Zcash, the set of
potential unspent coins is always growing, which means users cannot store a
concise representation of the blockchain. In Zcash, furthermore, users cannot
deny their participation in anonymous transactions. In this paper, we address
both of these limitations. By combining a technique we call updatable keys
with efficient zero-knowledge arguments, we propose a new cryptocurrency,
Quisquis, that achieves provably secure notions of anonymity while still
allowing users to deny participation and store a relatively small amount of
data.