We propose an end-to-end security scheme for mobility enabled healthcare Internet of Things (IoT).
The proposed scheme consists of (i) a secure and efficient end-user authentication and authorization
architecture based on the certificate based DTLS handshake, (ii) secure end-to-end communication based
on session resumption, and (iii) robust mobility based on interconnected smart gateways. The smart
gateways act as an intermediate processing layer (called fog layer) between IoT devices and sensors
(device layer) and cloud services (cloud layer). In our scheme, the fog layer facilitates ubiquitous mobility
without requiring any reconfiguration at the device layer. The scheme is demonstrated by simulation
and a full hardware/software prototype. Based on our analysis, our scheme has the most extensive set of
security features in comparison to related approaches found in literature. Energy-performance evaluation
results show that compared to existing approaches, our scheme reduces the communication overhead
by 26% and the communication latency between smart gateways and end users by 16%. In addition, our
scheme is approximately 97% faster than certificate based and 10% faster than symmetric key based DTLS.
Compared to our scheme, certificate based DTLS consumes about 2.2 times more RAM and 2.9 times more
ROM resources. On the other hand, the RAM and ROM requirements of our scheme are almost as low as
in symmetric key-based DTLS. Analysis of our implementation revealed that the handover latency caused
by mobility is low and the handover process does not incur any processing or communication overhead
on the sensors.