458
5 Methods of Detecting Hardware Trojans in Microcircuits
order to activate the potential state of a trigger. Such rare positions are determined
by statistical methods.
Salmani et al. [12] increase the likelihood of state changes of the start-up circuit
by inserting a special false trigger into the basic design. Also, false triggers are
performed as “scanning” triggers to preserve the original functionality.
5.1.5 Methods of Characterization of Logical Elements
for Detecting Trojans
In general, the analysis of third-party channels should ensure the detection of any
deviations from the expected behavior of a microcircuit caused by hardware Trojans.
Since the task of Trojans is precisely to be undetected during the functional testing
process, it is assumed that the impact of the Trojan is minimal compared to the overall
microcircuit activity.
This is a big problem for their detection, since the impact of the natural changes
of the process (manufacturing tolerance) is almost as serious as the impact of the
Trojan.
The aim of this approach is to attempt the characterization of each individual
logical element of an integrated circuit. In this case, performance levels, switching
power, and leakage current are used for characterization. Scale factors are calculated
to take into account natural manufacturing tolerances that cannot be avoided during
production. During such functional tests, scaling factors are measured using sidechannel analysis. If the test results of an integrated microcircuit are too different from
the calculated characteristics, then there is a high probability of introducing a Trojan
into this microcircuit, for the detection of which other methods and approaches are
required [36, 37].
5.1.6 Data Transmission Using Silent Trojans
An extremely interesting new class of Trojans was described by Lin et al. [2], who
presented a new technology called Malicious Off-Chip Leakage Enabled by SideChannels (MOLES), which allows for extraction of secret data using the so-called
distributed spectrum technology. Since the signal of the required extracted information is usually completely lost in the measuring noise, the definition of hidden
data transmission is almost impossible. However, Lin et al. [33] 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
5 Methods of Detecting Hardware Trojans in Microcircuits
order to activate the potential state of a trigger. Such rare positions are determined
by statistical methods.
Salmani et al. [12] increase the likelihood of state changes of the start-up circuit
by inserting a special false trigger into the basic design. Also, false triggers are
performed as “scanning” triggers to preserve the original functionality.
5.1.5 Methods of Characterization of Logical Elements
for Detecting Trojans
In general, the analysis of third-party channels should ensure the detection of any
deviations from the expected behavior of a microcircuit caused by hardware Trojans.
Since the task of Trojans is precisely to be undetected during the functional testing
process, it is assumed that the impact of the Trojan is minimal compared to the overall
microcircuit activity.
This is a big problem for their detection, since the impact of the natural changes
of the process (manufacturing tolerance) is almost as serious as the impact of the
Trojan.
The aim of this approach is to attempt the characterization of each individual
logical element of an integrated circuit. In this case, performance levels, switching
power, and leakage current are used for characterization. Scale factors are calculated
to take into account natural manufacturing tolerances that cannot be avoided during
production. During such functional tests, scaling factors are measured using sidechannel analysis. If the test results of an integrated microcircuit are too different from
the calculated characteristics, then there is a high probability of introducing a Trojan
into this microcircuit, for the detection of which other methods and approaches are
required [36, 37].
5.1.6 Data Transmission Using Silent Trojans
An extremely interesting new class of Trojans was described by Lin et al. [2], who
presented a new technology called Malicious Off-Chip Leakage Enabled by SideChannels (MOLES), which allows for extraction of secret data using the so-called
distributed spectrum technology. Since the signal of the required extracted information is usually completely lost in the measuring noise, the definition of hidden
data transmission is almost impossible. However, Lin et al. [33] 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