  The integration of cloud computing and Internet of Things (IoT) is quickly
becoming the key enabler for the digital transformation of the healthcare
industry by offering comprehensive improvements in patient engagements,
productivity and risk mitigation. This paradigm shift, while bringing numerous
benefits and new opportunities to healthcare organizations, has raised a lot of
security and privacy concerns. In this paper, we present a reliable, searchable
and privacy-preserving e-healthcare system, which takes advantage of emerging
cloud storage and IoT infrastructure and enables healthcare service providers
(HSPs) to realize remote patient monitoring in a secure and regulatory
compliant manner. Our system is built upon a novel dynamic searchable symmetric
encryption scheme with forward privacy and delegated verifiability for
periodically generated healthcare data. While the forward privacy is achieved
by maintaining an increasing counter for each keyword at an IoT gateway, the
data owner delegated verifiability comes from the combination of the Bloom
filter and aggregate message authentication code. Moreover, our system is able
to support multiple HSPs through either data owner assistance or delegation.
The detailed security analysis as well as the extensive simulations on a large
data set with millions of records demonstrate the practical efficiency of the
proposed system for real world healthcare applications.
