Paper 2013/638

DFA-Based Functional Encryption: Adaptive Security from Dual System Encryption

Somindu C. Ramanna

Abstract

We present an adaptively secure functional encryption (FE) scheme based on deterministic finite automata (DFA). The construction uses composite-order bilinear pairings and is built upon the selectively secure DFA-based FE scheme of Waters (Crypto 2012). The scheme is proven secure using the dual system methodology under static subgroup decision assumptions. A dual system proof requires generating of semi-functional components from the instance. In addition, these components must be shown to be properly distributed in an attacker's view. This can be ensured by imposing a restriction on the automata and strings over which the scheme is built i.e., every symbol can appear at most once in a string and in the set of transition tuples of an automata. First a basic construction with the restrictions is obtained and proved to be adaptively secure. We then show how to extend this basic scheme to a full scheme where the restrictions can be relaxed by placing a bound on the number of occurrences of any symbol in a string and in the set of transitions. With the relaxed restrictions, our system supports functionality defined by a larger class of regular languages.

Metadata
Available format(s)
PDF
Publication info
Preprint. MINOR revision.
Keywords
functional encryption (FE)deterministic finite automataFE over regular languagesdual system encryption
Contact author(s)
somindu_r @ isical ac in
History
2013-10-05: received
Short URL
https://ia.cr/2013/638
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2013/638,
      author = {Somindu C.  Ramanna},
      title = {{DFA}-Based Functional Encryption: Adaptive Security from Dual System Encryption},
      howpublished = {Cryptology {ePrint} Archive, Paper 2013/638},
      year = {2013},
      url = {https://eprint.iacr.org/2013/638}
}
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