On the privacy provisions of bloom filters in lightweight bitcoin clients

Arthur Gervais, Ghassan O. Karame, Damian Gruber, Srdjan Capkun

Research output: Chapter in Book/Report/Conference proceedingConference contribution

40 Citations (Scopus)

Abstract

Lightweight Bitcoin clients are gaining increasing adoption among Bitcoin users, owing to their reduced resource and bandwidth consumption. These clients support a simplified payment verification (SPV) mode as they are only required to download and verify a part of the block chain-thus supporting the usage of Bitcoin on constrained devices, such as smartphones. SPV clients rely on Bloom filters to receive transactions that are relevant to their local wallet. These filters embed all the Bitcoin addresses used by the SPV clients, and are outsourced to more powerful Bitcoin nodes which then only forward to those clients transactions relevant to their outsourced Bloom filters. In this paper, we explore the privacy of existing SPV clients. We show analytically and empirically that the reliance on Bloom filters within existing SPV clients leaks considerable information about the addresses of Bitcoin users. Our results show that an SPV client who uses a modest number of Bitcoin addresses (e.g., < 20) risks revealing almost all of his addresses. We also show that this information leakage is further exacerbated when users restart their SPV clients and/or when the adversary has access to more than one Bloom filter pertaining to the same SPV client. Motivated by these findings, we propose an efficient countermeasure to enhance the privacy of users which rely on SPV clients; our proposal can be directly integrated within existing SPV client implementations.

Original languageEnglish
Title of host publicationProceedings - 30th Annual Computer Security Applications Conference, ACSAC 2014
PublisherAssociation for Computing Machinery
Pages326-335
Number of pages10
Volume2014-December
EditionDecember
DOIs
Publication statusPublished - 8 Dec 2014
Event30th Annual Computer Security Applications Conference, ACSAC 2014 - New Orleans, United States
Duration: 8 Dec 201412 Dec 2014

Other

Other30th Annual Computer Security Applications Conference, ACSAC 2014
CountryUnited States
CityNew Orleans
Period8/12/1412/12/14

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  • Cite this

    Gervais, A., Karame, G. O., Gruber, D., & Capkun, S. (2014). On the privacy provisions of bloom filters in lightweight bitcoin clients. In Proceedings - 30th Annual Computer Security Applications Conference, ACSAC 2014 (December ed., Vol. 2014-December, pp. 326-335). Association for Computing Machinery. https://doi.org/10.1145/2664243.2664267