AuxChannel: enabling efficient bi-directional channel for scriptless blockchains

Zhimei Sui, Joseph K. Liu, Jiangshan Yu, Man Ho Au, Jia Liu

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

4 Citations (Scopus)


Payment channels have been a promising solution to blockchain scalability. While payment channels for script-empowered blockchains (such as Bitcoin and Ethereum) have been well studied, developing payment channels for scriptless blockchains (such as Monero) is considered challenging. In particular, nabling bidirectional payment on scriptless blockchains remains an open challenge. This work closes this gap by providing AuxChannel, the first bi-directional payment channel protocol for scriptless blockchains, meaning that building payment channels only requires the support of verifiably encrypted signature (aka adaptor signature) on the underlying blockchain. AuxChannel leverages verifiably encrypted signature to create a commitment for each off-chain payment and deploys a verifiable decentralised key escrow service to resolve dispute. To enable efficient construction of AuxChannel, we introduce a new cryptographic primitive, named Consecutive Verifiably Encrypted Signature (CVES), as a core building block and it can also be of independent interest for other applications. We provide and implement a provably secure instantiation on Schnorr-based CVES. We also provide a formal security analysis on the security of the AuxChannel.

Original languageEnglish
Title of host publicationProceedings of the 2022 ACM Asia Conference on Computer and Communications Security
EditorsMinoru Kuribayashi
Place of PublicationNew York NY USA
PublisherAssociation for Computing Machinery (ACM)
Number of pages15
ISBN (Electronic)9781450391405
Publication statusPublished - 2022
EventACM ASIA Conference on Computer and Communications Security 2022 - Online, Nagasaki, Japan
Duration: 30 May 20223 Jun 2022
Conference number: 17th (Proceedings) (Website)


ConferenceACM ASIA Conference on Computer and Communications Security 2022
Abbreviated titleASIA CCS 2022
Internet address


  • payment channel
  • scalability
  • scriptless blockchain

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