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area for automation manufacturers is to sell their au-
tomation systems expertise. This consists of main-
tenance, diagnostics, analysis and tuning (Helanter
¨
a
et al., 2004). There are usually a few experts on cer-
tain area and they are more and more mobile in global
scale. Also the customers with their subsidiaries op-
erate globally and are required to interconnect the of-
fices and plants to enable more accurate business tun-
ing. This brings new challenges also to the automa-
tion services support systems (ASSS).
Automation services support system have to cope
with many different type of network connections. The
most challenging part are the mobile connections due
to their unreliable and nondeterministic nature. Al-
though the connection to plant is rarely implemented
with mobile technologies the devices or device grids
are becoming more and more mobile. The ability to
take the mobile equipment into remote diagnostics
services will be strong asset in the future. The mo-
bility however will bring a totally different problem
area to normally local area network (LAN) based au-
tomation.
3 SECURITY THREATS
There are several different types of security treats that
must be taken into account when considering the data
security of the automation network. Valid users them-
selves are the most common threat any computer sys-
tem has. Intentional or unintentional misuse of com-
puter systems occurs commonly in every day opera-
tion. The system must also be fortified against unau-
thorised or improper use. This means that each user
has strictly defined role in the automation system,
and is only allowed to execute operation that corre-
spond to this role. Outside access, meaning access
from Internet, is also necessary to implement flexi-
ble operating environment for subcontractors and ser-
vice providers participating in plants production and
upkeep. However this access must be very care-
fully evaluated and controlled as any unauthorised use
could lead into catastrophic consequences e.g. loss or
theft of valuable information, process malfunction or
worse. Computer viruses create a whole new type of
data security threat. They can compromise even the
best of security, by executing code that allows unau-
thorised access by some third party. The complete
security analysis in networked automation is beyond
this paper. More complete study of the are can be
found in (Nikunen, 2001).
4 FEASIBLE SOLUTIONS –
PERVASIVE-UBIQUITOUS
SECURITY
Security design in automation network requires above
all careful thinking. The challenges come from vari-
ous, mostly quite old, field devices. Users and mod-
ern intelligent devices are usually not a problem since
they have the necessary computing power and inter-
faces.
Layered security architecture is the obvious choice.
This causes some overlapping security in some parts
but ensures that also the least capable devices are pro-
vided reasonable security. This also provides extra
security, if one layer is breached the second layer will
hold at least long enough that no important informa-
tion is lost. In practice this means securing data in
message level (OSI model: application layer) as well
as in TCP/UDP and IP levels (OSI model: transport
and network layers). Message level security with tra-
ditional field devices requires deployment of security
hubs. The main function of these hubs is, in addition
to converting oldish protocols to IP based routable
protocols, is to include the security into the commu-
nication by securing the messages. This implemen-
tation will bring in extra costs but reduces the total
cost compared to renewing all field devices into more
capable ones.
Solution to reasonable security can be achieved by
existing technologies. It is tools and ready made so-
lutions that lacking at the moment. Basis of almost
any security mechanism is identity. Without identify-
ing all entities participating in operation of a system,
we cannot enforce security. In its simplest this means
that we must know who the user, service or device is
in order to be able to make proper authorisation deci-
sions, encryption key selection and proper logging of
events occurring in the system.
Logging of security events is necessary because of
several reasons. It can be used to detect improper use
of the system by authorised personnel before secu-
rity or system operation is compromised. Logging
can also be used to track unauthorised use. The sys-
tem can then be reinforced against this particularat-
tack if necessary. This enables evolving security as
new threat are detected. In case of security is ever
breached, security logs can be used to determine crit-
icality of the breach. In fact without logging it may
well be impossible to ever detect some of the most
severe security breaches.
Encryption and signing of data is basic tool for data
security. Encryption protects data against unautho-
rised access and eavesdropping. Signing on the other
hand guarantees that the sender is who he claims to
be. Both of these methods rely on encryptions keys to
achieve their purpose. However they require a feasi-
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