Paper 2023/668
Statement-Oblivious Threshold Witness Encryption
, Technical University of Darmstadt, Bar-Ilan University, Technical University of Darmstadt, Technical University of DarmstadtAbstract
The notion of witness encryption introduced by Garg et al. (STOC'13) allows to encrypt a message under a statement $x$ from some NP-language $\mathcal{L}$ with associated relation $(x,w) \in \mathcal{R}$, where decryption can be carried out with the corresponding witness $w$. Unfortunately, known constructions for general-purpose witness encryption rely on strong assumptions, and are mostly of theoretical interest. To address these shortcomings, Goyal et al. (PKC'22) recently introduced a blockchain-based alternative, where a committee decrypts ciphertexts when provided with a valid witness w. Blockchain-based committee solutions have recently gained broad interest to offer security against more powerful adversaries and construct new cryptographic primitives. We follow this line of work, and propose a new notion of statement-oblivious threshold witness encryption. Our new notion offers the functionality of committee-based witness encryption while additionally hiding the statement used for encryption. We present two ways to build statement-oblivious threshold witness encryption, one generic transformation based on anonymous threshold identity-based encryption (A-TIBE) and one direct construction based on bilinear maps. Due to the lack of efficient A-TIBE schemes, the former mainly constitutes a feasibility result, while the latter yields a concretely efficient scheme.
Note: This is the full version of the paper of the same name published at CSF 2023.
Metadata
- Available format(s)
-
PDF
- Category
- Public-key cryptography
- Publication info
- Published elsewhere. CSF 2023
- Keywords
- Threshold Witness EncryptionStatement ObliviousnessCommittee-Based DecryptionThreshold Tag-Based Encryption
- Contact author(s)
-
david kretzler @ tu-darmstadt de
benjamin schlosser @ tu-darmstadt de - History
- 2023-05-11: approved
- 2023-05-11: received
- See all versions
- Short URL
- https://ia.cr/2023/668
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2023/668,
author = {Sebastian Faust and Carmit Hazay and David Kretzler and Benjamin Schlosser},
title = {Statement-Oblivious Threshold Witness Encryption},
howpublished = {Cryptology {ePrint} Archive, Paper 2023/668},
year = {2023},
url = {https://eprint.iacr.org/2023/668}
}
