A Lightweight CP-ABE Scheme for EHR over Cloud based on Blockchain and
Secure Multi-Party Computation
Abstract
With the growth of cloud computing and the popularity of
electronic health records (EHR), more and more patients and hospitals
are uploading EHR to the cloud for storage, retrieval and organization.
Due to the privacy of EHR, cloud-based EHR systems need to protect data
security and provide access control, and attribute-based encryption
(ABE) is the appropriate technology. Nevertheless, traditional
single-center ABE schemes do not conform to the collaborative scenario
of electronic health care, and some of them do not support real-time
attribute update. Consequently, this paper proposes a lightweight CP-ABE
scheme for EHR over cloud based on blockchain and secure multi-party
computation (LCBS). Firstly, we introduce the model of multi-authority
and innovatively apply secure multi-party computation to initialize the
system, which maintains normal system operation while the power is
decentralized. Secondly, we designed a blockchain suitable for EHR
systems to record the users’ key information, assisting multiple
entities to verify the key at different stages and protecting the EHR
from illegal acquisition. In addition, our scheme supports lightweight
attribute update, which requires small amount of computational overhead
to achieve instant attribute update. Finally, through formal security
analysis and simulation experiments of the LCBS system, it is shown that
our scheme guarantees data security and improves computing efficiency.
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