SwapCT: Swap Confidential Transactions for Privacy-Preserving Multi-Token Exchanges

Felix Engelmann, Lukas Müller, Andreas Peter, Frank Kargl, Christoph Bösch
2021 Proceedings on Privacy Enhancing Technologies  
Decentralized token exchanges allow for secure trading of tokens without a trusted third party. However, decentralization is mostly achieved at the expense of transaction privacy. For a fair exchange, transactions must remain private to hide the participants and volumes while maintaining the possibility for noninteractive execution of trades. In this paper we present a swap confidential transaction system (SwapCT) which is related to ring confidential transactions (e.g. used in Monero) but
more » ... rts multiple token types to trade among and enables secure, partial transactions for noninteractive swaps. We prove that SwapCT is secure in a strict, formal model and present its efficient performance in a prototype implementation with logarithmic signature sizes for large anonymity sets. For our construction we design an aggregatable signature scheme which might be of independent interest. Our SwapCT system thereby enables a secure and private exchange for tokens without a trusted third party.
doi:10.2478/popets-2021-0070 fatcat:2ed7l7c6grbnhedwl5pgt4rpfq