Cryptology ePrint Archive: Report 2018/582

Pisa: Arbitration Outsourcing for State Channels

Patrick McCorry and Surya Bakshi and Iddo Bentov and Andrew Miller and Sarah Meiklejohn

Abstract: State channels are a leading approach for improving the scalability of blockchains and cryptocurrencies. They allow a group of distrustful parties to optimistically execute an application-defined program amongst themselves, while the blockchain serves as a backstop in case of a dispute or abort. This effectively bypasses the congestion, fees and performance constraints of the underlying blockchain in the typical case. However, state channels introduce a new and undesirable assumption that a party must remain on-line and synchronised with the blockchain at all times to defend against execution fork attacks. An execution fork can revert a state channelís history, potentially causing financial damage to a party that is innocent except for having crashed. To provide security even to parties that may go off-line for an extended period of time, we present Pisa, a protocol enables such parties to delegate to a third party, called the custodian, to cancel execution forks on their behalf. To evaluate Pisa, we provide a proof-of-concept implementation for a simplified Sprites and we demonstrate that it is cost-efficient to deploy on the Ethereum network.

Category / Keywords: applications / state channels ethereum local consensus pisa custodian fair exchange

Date: received 6 Jun 2018

Contact author: stonecoldpat at gmail com

Available format(s): PDF | BibTeX Citation

Version: 20180606:185804 (All versions of this report)

Short URL: ia.cr/2018/582


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