Environmental Engineering Reference
In-Depth Information
Hardware Trojans in Safety
Important I&C Systems
Most of the vendors of FPGA chips do not have
their own manufacturing capacity: their task is in
development of designs of FPGA chips (that in-
cludes application of tools for design automation)
and placement of orders for their manufacturing
among appropriate foundries. Such factories play
important role in assurance of cyber security for
future chips, as well as in prevention from prob-
able vulnerabilities that can be caused by steal-
ing or modification of FPGA design during chip
manufacturing process.
On the other hand, vendors of FPGA chips
facilitate distribution and safety integration of
various IP-cores used by application designers
to encourage FPGA chips market. IP-core is
completed functional description intended for
integration into electronic design, which is be-
ing developed. IP-cores are being often used by
designers of FPGA-based applications to save
resources and time. IP-cores can be either in a form
of modules for hardware description languages
(HDL) or in a form of compiled netlists. So, such
IP-cores can introduce additional vulnerabilities
into applications, which use them. Supply chain
of chips is usually traceable and can be audited
that, however, does not reduce its importance from
FPGA cyber security assurance point of view.
Most of life cycle stages of FPGA chip are
implemented using software tools. Such tools
are usually used during design of printed circuit
boards, integrated circuits, developing FPGA elec-
tronic designs and simulation. Hence, developers
of tools for design automation play key role in
FPGA cyber security assurance and, in turn, can
cause vulnerabilities.
The objective of FPGA-based devices' cyber
security assurance should be solved at different
stages of hierarchy, as each of the stages has spe-
cific hardware or software vulnerabilities. Thus,
the objective of cyber security assurance should be
started from defining the boundaries of a system.
One of the threats in I&C systems for critical
applications is related to potential possibility of
Hardware Trojans (HT) insertion into hardware.
Hardware trojan is a harmful and intentionally hid-
den modification of electronic device (for example,
chip or its internal programmable configuration).
Such a modification can change functionality of a
device, which contains digital integrated circuits
and/or programmable components, or based on
FPGA technology that will lead to its malfunction
(for example, due to unpredictable failures and/
or faults) and, thus, dent confidence in a system
using this device.
Insertion of HT is possible at the stages of
development and manufacturing of both FPGA
chip and systems based on the chip.
At the modern stage of development of system
design technologies based on integrated circuits
and/or programmable components, existence of
a set of hardware trojans that have specific effect
on device operation (for example, FPGA chip),
in which they can be built in, is possible. Figure
7 depicts taxonomy, partly based on Karry R. et
al., (Karry, R. et al., 2010), of HT based on the
following attributes with specific features:
• A stage of chip life cycle (LC) at which HT
is inserted.
• Abstraction
level
of which HT
implementation.
• HT physical characteristics.
• HT activation mechanism.
• HT efect.
Each of the attributes is described below in
details.
HT insertion is possible at the following stages
of chip LC:
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