Cryptology ePrint Archive: Report 2012/468

Functional Encryption: New Perspectives and Lower Bounds

Shweta Agrawal and Sergey Gorbunov and Vinod Vaikuntanathan and Hoeteck Wee

Abstract: Functional encryption is an emerging paradigm for public-key encryption that enables fine-grained control of access to encrypted data. In this work, we present new perspectives on security definitions for functional encryption, as well as new lower bounds on what can be achieved. Our main contributions are as follows:

* We show a lower bound for functional encryption that satisfies a weak (non-adaptive) simulation-based security notion, via pseudo-random functions. This is the first lower bound that exploits unbounded collusions in an essential way.

* We put forth and discuss a simulation-based notion of security for functional encryption, with an unbounded simulator (called USIM). We show that this notion interpolates indistinguishability and simulation-based security notions, and has strong correlations to results and barriers in the zero-knowledge and multi-party computation literature.

Category / Keywords: public-key cryptography / Functional Encryption, Simulation-based Definitions, Pseudorandom Functions

Date: received 14 Aug 2012, last revised 1 Oct 2012

Contact author: vinodv at cs toronto edu

Available format(s): PDF | BibTeX Citation

Version: 20121001:203130 (All versions of this report)

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