Blockchain systems promise to mediate interactions of mutually distrusting parties without a trusted third party. However, protocols with full smart contract-based security are either limited in functionality or complex, with high costs for secured interactions. This observation leads to the development of protocol-specific schemes to avoid costly dispute resolution in case all participants remain honest. In this paper, we introduce SmartJudge, an extensible generalization of this trend for smart contract-based two-party protocols. SmartJudge relies on a protocol-independent mediator smart contract that moderates two-party interactions and only consults protocol-specific verifier smart contracts in case of a dispute. This way, SmartJudge avoids verification costs in absence of disputes and sustains interaction confidentiality among honest parties. We implement verifier smart contracts for cross-blockchain trades and exchanging digital goods and show that SmartJudge can reduce costs by 46-50% and 22% over current state of the art, respectively.
@inproceedings{2019-icbc-wagner-dispute-resolution,
author = {Wagner, Eric and V{\"o}lker, Achim and Fuhrmann, Frederik and Matzutt, Roman and Wehrle, Klaus},
title = {{Dispute Resolution for Smart Contract-based Two Party Protocols}},
year = {2019},
pages = {422-430},
keywords = {Ethereum,Bitcoin,smart contracts,two-party protocols,dispute resolution,cross-blockchain trades},
publisher = {IEEE},
booktitle = {IEEE International Conference on Blockchain and Cryptocurrency 2019 (ICBC 2019)},
ISBN = {978-1-7281-1328-9},
DOI = {10.1109/BLOC.2019.8751312},
}