Claudio Orlandi, Aarhus University
From 12.00 until 13.30
At CNB/F/110 (Lunch) + CAB/F/100.9 (Seminar), ETH Zurich
Universitätstrasse 6, 8092 Zurich
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.
Based on joint work with Prastudy Fauzi and Rebekah Mercer (Aaarhus University) and Sarah Meiklejohn (UCL London)