Cyber Physical Security Solutions for Pervasive Health Monitoring Systems - E-Healthcare Systems and Wireless Communications - page 161

hardened” (radiation, thermal) platforms.
However, as this is not universal, it can be
exploited. Attackers can artificially change
the environment around the cyber elements
of a CPS causing unexpected results with
CYPSec and normal operation of the CPS,
and denial of service. Protection against
physical attacks is therefore crucial for not
only CYPSec but also for CPS to function
correctly. However, this may not make
CYPSec solutions completely unusable,
as for many domains the environment may
be naturally secured. A case in point is a
PHM-CPS deployed on a patient's body.
CYPSec for such systems have used physi-
ological signals from the human body as a
means of addressing their security needs.
However, the human body is one of the
more secure environments in which CPSs
can be embedded. It is not easy to alter
its functioning, at least in a surreptitious
way. However, the same cannot be said for
power-grids where many substations are
unmanned. Therefore, if the physical pro-
cess itself is not secure, some mechanism
for authenticating the sensed value is re-
quired. However, most of the examples of
CPS fall somewhere in between the two in
terms of physical process security, as in the
case of CPSs deployed in smart data-cen-
ters (Tang, 2008) for reducing its cooling
cost. Attackers can potentially tamper with
the sensors in a datacenter requiring the air
conditioner to overload, but this would re-
quire physical access to the datacenter it-
self, a non-trivial task.

novel approach to securing PHMS, by viewing
them as cyber-physical systems (CPS). CPS is a
networked, monitoring and actuation platforms,
deeply embedded in specific physical processes.
CPS introduces a level of automation in managing
physical processes that has previously not been
achieved. This chapter focused on developing
solutions for securing PHM-CPS. In this regard,
we present a novel security paradigm for PHM-
CPS called Cyber-Physical Security (CYPSec)
solutions, which takes into account the environ-
mentally coupled nature of PHMS in its opera-
tion. We described the principal characteristics of
the CYPSec solutions and also give two diverse
example scenarios of their application. The first
utilized physiological signals for secure key
agreement, while the second is a proactive access
control model for emergency situations. A number
of issues need to be considered deploying CYPSec
solutions include notion of time and awareness of
mixed critical nature of the underlying CPS. Thus
far, we have only considered specific aspects of
securing PHM-CPS e.g. actuation with CAAC
and communication with PSKA. In the future
we plan to extend this in a more holistic manner,
taking into consideration all five (from sensing to
feedback) aspects of PHM-CPS security simul-
taneously, and trying to use CYPSec solutions to
address them. Some of the new issues that need to
be considered in such scenarios include - safety,
high-level system security policy specification and
management, and protection against vulnerabili-
ties afflicting PHM-CPS when they are connected
to larger cyber-only systems such as the Internet.

REFERENCES

Adelstein, F., Gupta, S. K., Richard, G. G., &
Schwiebert, L. (2005). Fundamentals of mobile
and pervasive computing . New York: McGraw
Hill.

CONCLUSION

In this chapter, we explored security solutions for
pervasive health monitoring systems. We take a