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

Linfeng Zhou

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 $FE$ to selective secure $FE$ through an approach called \textit{hybrid functional key generation}. Furthermore, our transformation preserves the compactness of the $FE$ 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 $FE$ 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 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 Encryption Minimal Assumptions Weakly Selective Security Selective Security iO
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: 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},
      url = {https://eprint.iacr.org/2016/848}
}