LightPIR: Privacy-Preserving Route Discovery for Payment Channel Networks

LightPIR: Privacy-Preserving Route Discovery for Payment Channel Networks

Abstract

Payment channel networks are a promising approach to improve the scalability of cryptocurrencies: they allow to perform transactions in a peer-to-peer fashion, along multi-hop routes in the network, without requiring consensus on the blockchain. However, during the discovery of cost-efficient routes for the transaction, critical information may be revealed about the transacting entities. This paper initiates the study of privacy-preserving route discovery mechanisms for payment channel networks. In particular, we present LightPIR, an approach which allows a source to efficiently discover a shortest path to its destination without revealing any information about the endpoints of the transaction. The two main observations which allow for an efficient solution in LightPIR are that: (1) surprisingly, hub labelling algorithms – which were developed to preprocess “street network like” graphs so one can later efficiently compute shortest paths – also work well for the graphs underlying payment channel networks, and that (2) hub labelling algorithms can be directly combined with private information retrieval. LightPIR relies on a simple hub labeling heuristic on top of existing hub labeling algorithms which leverages the specific topological features of cryptocurrency networks to further minimize storage and bandwidth overheads. In a case study considering the Lightning network, we show that our approach is an order of magnitude more efficient compared to a privacy-preserving baseline based on using private information retrieval on a database that stores all pairs shortest paths.

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Authors
  • Pietrzak, Krzysztof
  • Salem, Iosif
  • Schmid, Stefan
  • Yeo, Michelle
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Shortfacts
Category
Paper in Conference Proceedings or in Workshop Proceedings (Paper)
Event Title
20th IFIP Networking Conference 2021
Divisions
Communication Technologies
Subjects
Informatik Sonstiges
Theoretische Informatik
Event Location
Virtual Conference
Event Type
Conference
Event Dates
21-24 June 2021
Series Name
IFIP Networking Conference, IFIP Networking 2021, Espoo and Helsinki, Finland, June 21-24, 2021
ISSN/ISBN
978-1-6654-4501-6
Page Range
pp. 1-9
Date
24 June 2021
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