Hello,
we (Tim Ruffing, Pedro Moreno-Sanchez, and Aniket Kate) are group of researches at Saarland University in Germany.
We have written a research paper in which we propose a new coin mixing protocol to improve anonymity in Bitcoin. The protocol is called
CoinShuffle.
The key innovation is that it is
decentralized and it does not require a mixing server. Among other advantages, this means that
no mixing server learns which output addresses and input addresses in a mixing transaction belong together. Since CoinShuffle is based on the idea of CoinJoin, theft of coins is excluded as well. CoinShuffle does not require complex cryptography and performs well in practice, even in scenarios with a large number (about 50) of participants.
A preliminary version of
the paper is available.
This is the abstract:
The decentralized currency network Bitcoin is emerging as a potential new way for performing financial transactions across the globe. Its use of pseudonyms towards protecting users' privacy has been an attractive feature to many of its adopters. Nevertheless, due to the inherent public nature of the Bitcoin transaction ledger, users' privacy is severely restricted to linkable anonymity, and a few Bitcoin transaction deanonymization attacks have been reported so far.
In this paper, we propose CoinShuffle, a completely decentralized Bitcoin mixing protocol that allows users to utilize Bitcoin in a truly anonymous manner. CoinShuffle is inspired from the accountable anonymous group communication protocol Dissent and enjoys several advantages over its predecessor Bitcoin mixing protocols. It does not require any (trusted, accountable or untrusted) third party and it is perfectly compatible with the current Bitcoin system. CoinShuffle introduces only a small communication overhead for its users, while it completely avoids additional anonymization fees and minimizes the computation and communication overhead for the rest of the Bitcoin system.
A comparison to other approaches to improve anonymity, e.g., Zerocoin and Mixcoin, can be found in Section 8 in the paper.
We would be happy to hear your feedback and critique about our proposal. All details can be found in
the paper.