Return
Efficient Multi-Client Functional Encryption for Conjunctive Equality and Range Queries
DOI:10.1109/ACCESS.2022.3182330.png)
Abstract
En 中文
In multi-client functional encryption (MC-FE) for predicate queries, clients generate ciphertexts of plaintexts x(1), . . . ,x(n) binding with a time period T and store them on a cloud server, and the cloud server receives a function key corresponding to a predicate f from a trusted center and learns whether f (x(1), . . .,x(n)) = 1 or not by running the decryption algorithm on the multiple ciphertexts of the same time period. MC-FE for predicates can be used for a network event or medical data monitoring system based on time series data gathered by multiple clients. In this paper, we propose effcient MC-FE schemes that support conjunctive equality or range queries on encrypted data in the multi-client settings. First, we propose an effcient multi-client hidden vector encryption (MC-HVE) scheme in bilinear groups and prove the selective security with static corruptions. Our MC-HVE scheme is very effcient since a function key is composed of four group elements, a ciphertext consists of O(l) group elements where l is the size of a plaintext, and the decryption algorithm only requires four pairing operations. Second, we propose an effcient multi-client range query encryption (MC-RQE) scheme and prove the selective weak security with static corruptions. Our MC-RQE scheme which uses a binary tree is effcient since a ciphertext consists of O(log D) group elements and a function key consists of O(n log D) group elements where D is the maximum value of a range.
Keywords:
Functional encryption
predicate encryption
multi-client setting
hidden vector encryption
bilinear maps

