Redactable blockchain in the permissionless setting

Research output: Contribution to book/anthology/report/proceedingArticle in proceedingsResearchpeer-review

DOI

  • Dominic Deuber, Lehrstuhl für Theoretische Chemie/Computer Chemie Centrum, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany.
  • ,
  • Bernardo Magri
  • Sri Aravinda Krishnan Thyagarajan, Lehrstuhl für Theoretische Chemie/Computer Chemie Centrum, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany.

Bitcoin is an immutable permissionless blockchain system that has been extensively used as a public bulletin board by many different applications that heavily relies on its immutability. However, Bitcoin's immutability is not without its fair share of demerits. Interpol exposed the existence of harmful and potentially illegal documents, images and links in the Bitcoin blockchain, and since then there have been several qualitative and quantitative analysis on the types of data currently residing in the Bitcoin blockchain. Although there is a lot of attention on blockchains, surprisingly the previous solutions proposed for data redaction in the permissionless setting are far from feasible, and require additional trust assumptions. Hence, the problem of harmful data still poses a huge challenge for law enforcement agencies like Interpol (Tziakouris, IEEE S&P'18). We propose the first efficient redactable blockchain for the permissionless setting that is easily integrable into Bitcoin, and that does not rely on heavy cryptographic tools or trust assumptions. Our protocol uses a consensus-based voting and is parameterised by a policy that dictates the requirements and constraints for the redactions; if a redaction gathers enough votes the operation is performed on the chain. As an extra feature, our protocol offers public verifiability and accountability for the redacted chain. Moreover, we provide formal security definitions and proofs showing that our protocol is secure against redactions that were not agreed by consensus. Additionally, we show the viability of our approach with a proof-of-concept implementation that shows only a tiny overhead in the chain validation of our protocol when compared to an immutable one.

Original languageEnglish
Title of host publicationProceedings - 2019 IEEE Symposium on Security and Privacy, SP 2019
Number of pages15
PublisherIEEE
Publication year2019
Pages124-138
Article number8835372
ISBN (Electronic)9781538666609
DOIs
Publication statusPublished - 2019
Event40th IEEE Symposium on Security and Privacy, SP 2019 - San Francisco, United States
Duration: 19 May 201923 May 2019

Conference

Conference40th IEEE Symposium on Security and Privacy, SP 2019
LandUnited States
BySan Francisco
Periode19/05/201923/05/2019
SponsorCS Financial

    Research areas

  • Bitcoin, Blockchain, GDPR, Redactable-Blockchain

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