Paper 2017/319

Embed-Augment-Recover: Function Private Predicate Encryption from Minimal Assumptions in the Public-Key Setting

Sikhar Patranabis and Debdeep Mukhopadhyay

Abstract

We present a new class of public-key predicate encryption schemes that are provably function private in the standard model under well-known cryptographic assumptions, and assume predicate distributions satisfying realistic min-entropy requirements. More concretely, we present public-key constructions for identity-based encryption (IBE) and inner-product encryption (IPE) that are computationally function private in the standard model under a family of weaker variants of the DLIN assumption. Existing function private constructions in the public-key setting impose highly stringent requirements on the min-entropy of predicate distributions, thereby limiting their applicability in the context of real-world predicates. For example, the statistically function private constructions of Boneh, Raghunathan and Segev (CRYPTO'13 and ASIACRYPT'13) are inherently restricted to predicate distributions with min-entropy roughly proportional to $\lambda$, where $\lambda$ is the security parameter. Our constructions allow relaxing this min-entropy requirement to $\omega(\log\lambda)$, while achieving a computational notion of function privacy against probabilistic polynomial-time adversaries, which suffices for most real-world applications. Our constructions also avoid the need for strong assumptions such as indistinguishability obfuscation.

Note: The paper is augmented with a revised related work section

Metadata
Available format(s)
PDF
Publication info
Preprint. MINOR revision.
Keywords
Predicate EncryptionPublic-KeyFunction PrivacyComputational IndistinguishabilityMin-EntropyIdentity-Based EncryptionInner-Product Encryption
Contact author(s)
sikhar patranabis @ iitkgp ac in
History
2017-09-18: last of 66 revisions
2017-04-14: received
See all versions
Short URL
https://ia.cr/2017/319
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2017/319,
      author = {Sikhar Patranabis and Debdeep Mukhopadhyay},
      title = {Embed-Augment-Recover: Function Private Predicate Encryption from Minimal Assumptions in the Public-Key Setting},
      howpublished = {Cryptology ePrint Archive, Paper 2017/319},
      year = {2017},
      note = {\url{https://eprint.iacr.org/2017/319}},
      url = {https://eprint.iacr.org/2017/319}
}
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