Cryptology ePrint Archive: Report 2016/561
Compactness vs Collusion Resistance in Functional Encryption
Baiyu Li and Daniele Micciancio
Abstract: We present two general constructions that can be used to combine any
encryption (FE) schemes (supporting a bounded number of key queries)
into a new functional encryption scheme supporting
a larger number of key queries.
By using these constructions iteratively,
we transform any primitive FE scheme supporting a single
functional key query (from a sufficiently general class of functions)
and has certain weak compactness properties to a collusion-resistant
FE scheme with the same or slightly weaker compactness properties.
Together with previously known reductions, this
shows that the compact, weakly compact, collusion-resistant, and
weakly collusion-resistant versions of FE are all equivalent
under polynomial time reductions.
These are all FE variants known to imply the existence of indistinguishability
obfuscation, and were previously thought to offer slightly different avenues toward
the realization of obfuscation from general assumptions.
Our results show that they are indeed all equivalent, improving our
understanding of the minimal assumptions on
functional encryption required to instantiate
Category / Keywords: public-key cryptography / Functional encryption, reduction, compact, collusion resistance
Date: received 2 Jun 2016
Contact author: baiyu at cs ucsd edu, daniele at cs ucsd edu
Available format(s): PDF | BibTeX Citation
Note: Submitted to TCC 2016-B
Version: 20160603:162154 (All versions of this report)
Short URL: ia.cr/2016/561
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