Making any identity-based encryption accountable, efficiently

Aggelos Kiayias, Qiang Tang

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

11 Scopus citations


Identity-Based Encryption (IBE) provides a compelling solution to the PKI management problem, however it comes with the serious privacy consideration that a trusted party (called the PKG) is required to generate (and hence also know) the secret keys of all users. This inherent key escrow problem is considered to be one of the major reasons hindering the wider utilization of IBE systems. In order to address this problem, Goyal [20] introduced the notion of accountable authority IBE (A-IBE), in which a judge can differentiate the PKG from the user as the source of a decryption software. Via this “tracing” mechanism, A-IBE deters the PKG from leaking the user’s secret key and hence offers a defense mechanism for IBE users against a malicious PKG. All previous works on A-IBE focused on specialized constructions trying to achieve different properties and efficiency enhancements. In this paper for the first time we show how to add accountability to any IBE scheme using oblivious transfer (OT), with almost the same ciphertext efficiency as the underlying IBE. Furthermore, we extend our generic construction to support identity reuse without losing efficiency. This property is desirable in practice as users may accidentally lose their secret keys and they -naturally- prefer not to abandon their identities. How to achieve this property was open until our work. Along the way, we first modify the generic construction and develop a new technique to provide public traceability generically.

Original languageEnglish (US)
Title of host publicationComputer Security – ESORICS 2015 - 20th European Symposium on Research in Computer Security, Proceedings
EditorsPeter Y.A. Ryan, Günther Pernul, Edgar Weippl
PublisherSpringer Verlag
Number of pages21
ISBN (Print)9783319241739
StatePublished - 2015
Externally publishedYes
Event20th European Symposium on Research in Computer Security, ESORICS 2015 - Vienna, Austria
Duration: Sep 21 2015Sep 25 2015

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Other20th European Symposium on Research in Computer Security, ESORICS 2015

All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • General Computer Science


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