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

Felix Engelmann; Lukas Müller; Andreas Peter; Frank Kargl; Christoph Bösch

Paper 2021/631

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

Felix Engelmann

, Aarhus University

Lukas Müller, Ulm University

Andreas Peter, University of Twente

Frank Kargl

, Ulm University

Christoph Bösch

, Ulm University

Abstract

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 non-interactive 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 supports multiple token types to trade among and enables secure, partial transactions for non-interactive 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.

Note: Fixed minor copy paste error in the appendix.

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Published elsewhere. PETS 2021
Keywords: atomic swap zero-knowledge aggregation typed tokens
Contact author(s): fe-research @ nlogn org
lukas mueller @ alumni uni-ulm de
a peter @ utwente nl
frank kargl @ uni-ulm de
christoph boesch @ uni-ulm de
History: 2022-08-30: revised; 2021-05-17: received; See all versions
Short URL: https://ia.cr/2021/631
License: CC BY

BibTeX

@misc{cryptoeprint:2021/631,
      author = {Felix Engelmann and Lukas Müller and Andreas Peter and Frank Kargl and Christoph Bösch},
      title = {{SwapCT}: Swap Confidential Transactions for Privacy-Preserving Multi-Token Exchanges},
      howpublished = {Cryptology {ePrint} Archive, Paper 2021/631},
      year = {2021},
      url = {https://eprint.iacr.org/2021/631}
}