Paper 2016/848

From Weakly Selective to Selective Security in Compact Functional Encryption, Revisited

Linfeng Zhou

Abstract

We provide a generic transformation from weakly selective secure \(\mathsf{FE}\) to selective secure \(\mathsf{FE}\) through an approach called \textit{hybrid functional key generation}. Furthermore, our transformation preserves the compactness of the \(\mathsf{FE}\) scheme. Additionally, we note that this transformation is much simpler than the prior work \cite{garg2016single}. We consider the simplicity of the construction in this work as a positive feature and the hybrid functional key generation approach as a new method that can be applied in functional encryption schemes. Furthermore, we try to weaken the input \(\mathsf{FE}\) scheme of our transformation to be a non-compact one instead of a fully-compact one, by additionally assuming the hardness of LWE (or Ring-LWE) assumption. We achieve this result by utilizing the \(\mathsf{FE}\) scheme for bounded collusions with \textit{decomposable and succinct ciphertext property}, which can be solely based on the LWE (or Ring-LWE) assumption. Finally we present the implications of our result, which improves previous results, in building general-purpose indistinguishability obfuscator from (well-expressed) functional encryption.

Note: Extended results.

Metadata
Available format(s)
PDF
Publication info
Preprint. MINOR revision.
Keywords
Functional EncryptionMinimal AssumptionsWeakly Selective SecuritySelective SecurityiO
Contact author(s)
daniel linfeng zhou @ gmail com
History
2017-02-18: last of 5 revisions
2016-09-07: received
See all versions
Short URL
https://ia.cr/2016/848
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2016/848,
      author = {Linfeng Zhou},
      title = {From Weakly Selective to Selective Security in Compact Functional Encryption, Revisited},
      howpublished = {Cryptology ePrint Archive, Paper 2016/848},
      year = {2016},
      note = {\url{https://eprint.iacr.org/2016/848}},
      url = {https://eprint.iacr.org/2016/848}
}
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