318
4 Hardware Trojans in Microcircuits
into relevant categories. In this case, the officials acted on the basis of the following
obvious considerations:
• Classification of Trojans will make it possible to study their characteristics on a
systematic basis.
• It is possible to develop specific identification and mitigation methods for every
category of hardware Trojans.
• It is possible to design separate assessment criteria for each category of Trojans,
which can be used as a basis for comparing and determining efficiency of various
methods of Trojan detection.
Below is an attempt of creating such general (basic) classification of hardware
Trojans, which mostly corresponds to these consideration.
Unfortunately, we have to acknowledge that as of the moment of publication of this
book, there are almost no serious academic book, reference book, practical guides,
let alone technical encyclopedias dedicated to this new hazard, where all generally
accepted and established terms, definitions, and classification systems would be
presented.
Therefore, we present here various forms of classification of the researched
subject, which are most frequently used by researchers and based on the results
of the analysis performed by the authors and generalization of previously published
information.
Of course, besides the classification of Trojan types, we will need to bring to a
common standard various existing classifications of Trojans based on methods of
their activation, identification, etc.
4.3.2 General Classification of Hardware Trojans
According to the results of analysis of numerous publications by researchers of the
subject, all known hardware Trojans can be classified based on five main attributes:
(1) The stage of development during which the microcircuit was attacked;
(2) The exact level of the hardware abstraction (architecture) attacked;
(3) The way of activation of the hardware Trojan in the microcircuit;
(4) The results of the final effect of the Trojan on the attacked system; and
(5) Physical (geometrical) position of the Trojan.
For example, in the work [130], Trojans are classified based only on their physical
features, activation mechanisms, and end functionality. The authors of the work [127]
tried to substantiate their classification and its criteria using the structure of a simple
Trojan shown in Fig. 4.24.
Since the main goal of our book is to familiarize developers of critical microcircuits with the specific features of manifestation of this new problem, let us consider
theoretical and practical aspects of this issue in detail.
4 Hardware Trojans in Microcircuits
into relevant categories. In this case, the officials acted on the basis of the following
obvious considerations:
• Classification of Trojans will make it possible to study their characteristics on a
systematic basis.
• It is possible to develop specific identification and mitigation methods for every
category of hardware Trojans.
• It is possible to design separate assessment criteria for each category of Trojans,
which can be used as a basis for comparing and determining efficiency of various
methods of Trojan detection.
Below is an attempt of creating such general (basic) classification of hardware
Trojans, which mostly corresponds to these consideration.
Unfortunately, we have to acknowledge that as of the moment of publication of this
book, there are almost no serious academic book, reference book, practical guides,
let alone technical encyclopedias dedicated to this new hazard, where all generally
accepted and established terms, definitions, and classification systems would be
presented.
Therefore, we present here various forms of classification of the researched
subject, which are most frequently used by researchers and based on the results
of the analysis performed by the authors and generalization of previously published
information.
Of course, besides the classification of Trojan types, we will need to bring to a
common standard various existing classifications of Trojans based on methods of
their activation, identification, etc.
4.3.2 General Classification of Hardware Trojans
According to the results of analysis of numerous publications by researchers of the
subject, all known hardware Trojans can be classified based on five main attributes:
(1) The stage of development during which the microcircuit was attacked;
(2) The exact level of the hardware abstraction (architecture) attacked;
(3) The way of activation of the hardware Trojan in the microcircuit;
(4) The results of the final effect of the Trojan on the attacked system; and
(5) Physical (geometrical) position of the Trojan.
For example, in the work [130], Trojans are classified based only on their physical
features, activation mechanisms, and end functionality. The authors of the work [127]
tried to substantiate their classification and its criteria using the structure of a simple
Trojan shown in Fig. 4.24.
Since the main goal of our book is to familiarize developers of critical microcircuits with the specific features of manifestation of this new problem, let us consider
theoretical and practical aspects of this issue in detail.