An efficient and revocable attribute-based data sharing scheme with rich expression and escrow freedom

Attribute-based encryption effectively realizes fine-grained access control by using attri-butes. It provides an ideal access control strategy for new computing environments with large-scale, strong dynamics and strong privacy characteristics, such as cloud computing and the Internet of things. In this paper, we propose an efficient and provably secure cloud data sharing scheme (ABEDS -RR) using ciphertext policy attributed-based encryption. The ABEDS -RR scheme needs a semi-trusted proxy party to transform part of the ciphertext with a conversion key. Compared with most existing schemes, when changing the attri-butes of a user, only the private key and conversion key of the user need to be modified. In order to better adapt to occasions with limited computing capacity, such as ad hoc net-work, smart sensor, mobile device, the scheme can be extended to the case of outsourcing decryption. In addition, the ABEDS -RR scheme overcomes key escrow issues by co -generating user keys between two entities, and enriches the expression ability of attributes by introducing weight attributes. (c) 2022 Elsevier Inc. All rights reserved.