### An Equivalence Between Attribute-Based Signatures and Homomorphic Signatures, and New Constructions for Both

Rotem Tsabary

##### Abstract

In Attribute-Based Signatures (ABS; first defined by Maji, Prabhakaran and Rosulek, CT-RSA 2011) an authority can generate multiple signing keys, where each key is associated with a constraint $f$. A key respective to $f$ can sign a message $x$ only if $f(x) = 0$. The security requirements are unforgeability and key privacy (signatures should not expose the specific signing key used). In Homomorphic Signatures (HS; first defined by Boneh and Freeman, PKC 2011), given a signature for a data-set $x$, one can evaluate a signature for the pair $(f(x),f)$, for functions $f$. In context-hiding HS, evaluated signatures do not reveal information about the pre-evaluated signature. In this work we start by showing that these two notions are in fact equivalent. The first implication of this equivalence is a new lattice-based ABS scheme for polynomial-depth circuits, based on the HS construction of Gorbunov, Vaikuntanathan and Wichs (GVW; STOC 2015). We then construct a new ABS candidate from a worst case lattice assumption (SIS), with different parameters. Using our equivalence again, now in the opposite direction, our new ABS implies a new lattice-based HS scheme with different parameter trade-off, compared to the aforementioned GVW.

Available format(s)
Publication info
A minor revision of an IACR publication in TCC 2017
Keywords
digital signatureshomomorphic signaturesattribute-based signaturespolicy-based signaturesABSPBSlattice techniques
Contact author(s)
rotem tsabary @ weizmann ac il
History
2018-01-24: last of 3 revisions
See all versions
Short URL
https://ia.cr/2017/723

CC BY

BibTeX

@misc{cryptoeprint:2017/723,
author = {Rotem Tsabary},
title = {An Equivalence Between Attribute-Based Signatures and Homomorphic Signatures, and New Constructions for Both},
howpublished = {Cryptology ePrint Archive, Paper 2017/723},
year = {2017},
note = {\url{https://eprint.iacr.org/2017/723}},
url = {https://eprint.iacr.org/2017/723}
}

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