## CryptoDB

### Paper: Fine-grained Secure Attribute-based Encryption

Authors: Yuyu Wang , University of Electronic Science and Technology of China Jiaxin Pan , NTNU – Norwegian University of Science and Technology Yu Chen , Shandong University Search ePrint Search Google Slides CRYPTO 2021 Fine-grained cryptography is constructing cryptosystems in a setting where an adversary’s resource is a-prior bounded and an honest party has less resource than an adversary. Currently, only simple form of encryption schemes, such as secret-key and public-key encryption, are constructed in this setting. In this paper, we enrich the available tools in fine-grained cryptography by proposing the first fine-grained secure attribute-based encryption (ABE) scheme. Our construction is adaptively secure under the widely accepted worst-case assumption, $NC1 \subsetneq \oplus L/poly$, and it is presented in a generic manner using the notion of predicate encodings (Wee, TCC’14). By properly instantiating the underlying encoding, we can obtain different types of ABE schemes, including identity-based encryption. Previously, all of these schemes were unknown in fine-grained cryptography. Our main technical contribution is constructing ABE schemes without using pairing or the Diffie-Hellman assumption. Hence, our results show that, even if one-way functions do not exist, we still have ABE schemes with meaningful security. For more application of our techniques, we construct an efficient (quasi-adaptive) non-interactive zero-knowledge (QA-NIZK) proof system.
##### BibTeX
@inproceedings{crypto-2021-31236,
title={Fine-grained Secure Attribute-based Encryption},
publisher={Springer-Verlag},
author={Yuyu Wang and Jiaxin Pan and Yu Chen},
year=2021
}