Title: Conditional proxy broadcast re-encryption with fine grain policy for cloud data sharing

Authors: Maosheng Sun; Chunpeng Ge; Liming Fang; Jiandong Wang

Addresses: College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China; Department of Information Center, Yangzhou University, Yangzhou, China ' Department of Computer Engineering, Jiangsu University of Technology, Changzhou, China ' College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China ' College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, China

Abstract: Conditional proxy broadcast re-encryption (CPBRE) enables a semi-trusted proxy to convert Alice's ciphertext satisfying a certain condition into a set of users' ciphertext. The proxy, however, cannot learn anything about the underlying plaintext. The traditional CPBRE schemes cannot support flexible control on conditions. In this paper, we present a new primitive named conditional proxy broadcast re-encryption with fine grain policy (CPBRE-FG). In a CPBRE-FG scheme, the re-encryption key is generated with an access tree, and the ciphertext is constructed under a set of descriptive conditions. The proxy can convert a ciphertext if and only if the set of conditions satisfies the access tree. We formalise the notion of CPBRE-FG and present an efficient CPBRE-FG scheme. Finally, we prove it against chosen-ciphertext attack (CCA) security in the random oracle model.

Keywords: conditional proxy re-encryption; proxy broadcast re-encryption; access policy; random oracle model.

DOI: 10.1504/IJES.2019.098296

International Journal of Embedded Systems, 2019 Vol.11 No.2, pp.115 - 124

Received: 12 Jan 2017
Accepted: 24 Apr 2017
Published online: 13 Mar 2019 *

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