Provably secure key-aggregate cryptosystems with auxiliary inputs for data sharing on the cloud

摘要

In the applications of Internet of Things (IoT), users usually do not believe that the cloud server is doing a good job of confidentiality, and thus the private data/documents are encrypted and maintained in the cloud storage. And then, fine-grained data sharing of these encrypted data for increased efficiency is an important requirement. Key-aggregate cryptosystem (KAC) has been proposed to address this problem, which can realize efficient delegation of decryption rights of any subset of ciphertexts. However, the end-devices of IoT may not have the special trusted hardware, and the stored keys are apt to be leaked by side-channel attacks. To solve this problem, we design two leakage-resilient KAC schemes, which can be proved secure with auxiliary input. We also implement these schemes over two platforms to test their applicability for the resource-constrained devices. (C) 2017 Elsevier B.V. All rights reserved.