Simulation without the Artificial Abort:  Simplified Proof and Improved Concrete Security for Waters' IBE Scheme

Mihir Bellare; Thomas Ristenpart

Paper 2009/084

Simulation without the Artificial Abort: Simplified Proof and Improved Concrete Security for Waters' IBE Scheme

Mihir Bellare and Thomas Ristenpart

Abstract

Waters' variant of the Boneh-Boyen IBE scheme is attractive because of its efficency, applications, and security attributes,but suffers from a relatively complex proof with poor concrete security. This is due in part to the proof's ``artificial abort'' step, which has then been inherited by numerous derivative works. It has often been asked whether this step is necessary. We show that it is not, providing a new proof that eliminates this step. The new proof is not only simpler than the original one but offers better concrete security for important ranges of the parameters. As a result, one can securely use smaller groups, resulting in significant efficiency improvements.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Published elsewhere. To appear at Eurocrypt 2009
Keywords: identity-based encryption
Contact author(s): tristenp @ cs ucsd edu
History: 2009-02-24: received
Short URL: https://ia.cr/2009/084
License: CC BY

BibTeX

@misc{cryptoeprint:2009/084,
      author = {Mihir Bellare and Thomas Ristenpart},
      title = {Simulation without the Artificial Abort:  Simplified Proof and Improved Concrete Security for Waters' {IBE} Scheme},
      howpublished = {Cryptology {ePrint} Archive, Paper 2009/084},
      year = {2009},
      url = {https://eprint.iacr.org/2009/084}
}