### Fully Secure Attribute-Based Encryption for $t$-CNF from LWE

Rotem Tsabary

##### Abstract

Attribute-based Encryption (ABE), first introduced by [SW05,GPSW06], is a public key encryption system that can support multiple users with varying decryption permissions. One of the main properties of such schemes is the supported function class of policies. While there are fully secure constructions from bilinear maps for a fairly large class of policies, the situation with lattice-based constructions is less satisfactory and many efforts were made to close this gap. Prior to this work the only known fully secure lattice construction was for the class of point functions (also known as IBE). In this work we construct for the first time a lattice-based (ciphertext-policy) ABE scheme for the function class $t$-CNF, which consists of CNF formulas where each clause depends on at most $t$ bits of the input, for any constant $t$. This class includes NP-verification policies, bit-fixing policies and $t$-threshold policies. Towards this goal we also construct a fully secure single-key constrained PRF from OWF for the same function class, which might be of independent interest.

Available format(s)
Category
Public-key cryptography
Publication info
Preprint. Minor revision.
Keywords
attribute-based encryptionABEciphertext policyfull securityadaptive securityconstrained PRFlattice techniquesLWE
Contact author(s)
rotem tsabary @ weizmann ac il
History
2019-06-02: last of 2 revisions
See all versions
Short URL
https://ia.cr/2019/365

CC BY

BibTeX

@misc{cryptoeprint:2019/365,
author = {Rotem Tsabary},
title = {Fully Secure Attribute-Based Encryption for $t$-CNF from LWE},
howpublished = {Cryptology ePrint Archive, Paper 2019/365},
year = {2019},
note = {\url{https://eprint.iacr.org/2019/365}},
url = {https://eprint.iacr.org/2019/365}
}

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