Paper 2017/1069

Non-Malleability vs. CCA-Security: The Case of Commitments

Brandon Broadnax, Valerie Fetzer, Jörn Müller-Quade, and Andy Rupp

Abstract

In this work, we settle the relations among a variety of security notions related to non-malleability and CCA-security that have been proposed for commitment schemes in the literature. Interestingly, all our separations follow from two generic transformations. Given two appropriate security notions X and Y from the class of security notions we compare, these transformations take a commitment scheme that fulfills notion X and output a commitment scheme that still fulfills notion X but not notion Y. Using these transformations, we are able to show that some of the known relations for public-key encryption do not carry over to commitments. In particular, we show that, surprisingly, parallel non-malleability and parallel CCA-security are not equivalent for commitment schemes. This stands in contrast to the situation for public-key encryption where these two notions are equivalent as shown by Bellare et al. at CRYPTO ‘99.

Metadata
Available format(s)
PDF
Publication info
Published by the IACR in PKC 2018
Keywords
non-malleabilityCCA securitycommitmentssecurity definitions
Contact author(s)
brandon broadnax @ kit edu
History
2018-01-09: revised
2017-11-10: received
See all versions
Short URL
https://ia.cr/2017/1069
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2017/1069,
      author = {Brandon Broadnax and Valerie Fetzer and Jörn Müller-Quade and Andy Rupp},
      title = {Non-Malleability vs. CCA-Security: The Case of Commitments},
      howpublished = {Cryptology ePrint Archive, Paper 2017/1069},
      year = {2017},
      note = {\url{https://eprint.iacr.org/2017/1069}},
      url = {https://eprint.iacr.org/2017/1069}
}
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