342
4 Hardware Trojans in Microcircuits
Kim et al. [167] propose the use of special bus architecture, protected from Trojans,
for system-on-chips. Such an architecture can detect the very fact of unauthorized
access to the bus. To prevent DoS attacks, the direct allocation of a bus to one of the
nodes is blocked by limiting the maximum bus allocation time. This method will be
discussed in more detail in the following chapters.
4.6.2.6 Data Transmission by “Silent” Trojans
A new class of Trojans was described in Lina et al. [195], where authors present a
technology called MOLES (malicious off-chip leakage enabled by side channels),
allowing you to extract sensitive data using the so-called “distributed spectrum technology.” Since the signal of the extracted information is usually completely lost in
the measuring noise, the definition of hidden data transmission is almost impossible. However, Lin et al. [143] describe the ability to transmit data by modulating a
power source signal using spread spectrum technology. Figuratively speaking, this
technology uses large capacities, “attracting” current in the process of charging.
Depending on what value will be transferred (one or zero), the capacity will or will
not be charged. Such charging current, encoded using the special distributed spectrum technology, can already be analyzed by analyzing the supply current through a
third-party channel.
4.6.2.7 Protection for Multi-core Architectures
Another approach to detecting Trojans in multi-core systems was proposed by Mcintrier et al. [174]. Within this approach, the executable software is variable while
maintaining functional equivalence. This result can be achieved through the use of
different sets of alternative algorithms, with different versions of software running
on several cores. If one of the software versions matches the condition for activating
the installed Trojan, while activating it, the results of the two calculations will be
different. That way, a Trojan can be detected and isolated at runtime. In fact, this
method is a development of the majority data transfer method that has been known
for more than half a century, when the information that is completely matched on
two of the three channels is considered true.
4.6.2.8 Using the Definition at Runtime
Another interesting method, the so-called BlueChip approach, proposed by Hicks
et al. [164], is based on the use of additional hardware modules. It is designed to
make hardware Trojans installed at the design stage harmless at runtime.
Trojans are isolated here by replacing “suspicious” contours with their software emulation. Suspicious contours are detected by identifying unused contours—a
method that allows you to monitor the activity of the contour during functional testing.
4 Hardware Trojans in Microcircuits
Kim et al. [167] propose the use of special bus architecture, protected from Trojans,
for system-on-chips. Such an architecture can detect the very fact of unauthorized
access to the bus. To prevent DoS attacks, the direct allocation of a bus to one of the
nodes is blocked by limiting the maximum bus allocation time. This method will be
discussed in more detail in the following chapters.
4.6.2.6 Data Transmission by “Silent” Trojans
A new class of Trojans was described in Lina et al. [195], where authors present a
technology called MOLES (malicious off-chip leakage enabled by side channels),
allowing you to extract sensitive data using the so-called “distributed spectrum technology.” Since the signal of the extracted information is usually completely lost in
the measuring noise, the definition of hidden data transmission is almost impossible. However, Lin et al. [143] describe the ability to transmit data by modulating a
power source signal using spread spectrum technology. Figuratively speaking, this
technology uses large capacities, “attracting” current in the process of charging.
Depending on what value will be transferred (one or zero), the capacity will or will
not be charged. Such charging current, encoded using the special distributed spectrum technology, can already be analyzed by analyzing the supply current through a
third-party channel.
4.6.2.7 Protection for Multi-core Architectures
Another approach to detecting Trojans in multi-core systems was proposed by Mcintrier et al. [174]. Within this approach, the executable software is variable while
maintaining functional equivalence. This result can be achieved through the use of
different sets of alternative algorithms, with different versions of software running
on several cores. If one of the software versions matches the condition for activating
the installed Trojan, while activating it, the results of the two calculations will be
different. That way, a Trojan can be detected and isolated at runtime. In fact, this
method is a development of the majority data transfer method that has been known
for more than half a century, when the information that is completely matched on
two of the three channels is considered true.
4.6.2.8 Using the Definition at Runtime
Another interesting method, the so-called BlueChip approach, proposed by Hicks
et al. [164], is based on the use of additional hardware modules. It is designed to
make hardware Trojans installed at the design stage harmless at runtime.
Trojans are isolated here by replacing “suspicious” contours with their software emulation. Suspicious contours are detected by identifying unused contours—a
method that allows you to monitor the activity of the contour during functional testing.