CRITERIA AND CLASSIFICATION OF HARDWARE ATTACKS Hardware attacks can be measured along three dimensions or criteria: accessibility, recourses, and time. According to the ART (Accessibility, Resources, Time) scheme introduced in [1], one can quantize the degree of attack severity into three levels along each of the three dimensions. A. Accessibility • Limited Access: The attacker has no physical connection/contact to the hardware. • Partial Access: The attacker can connect to or scan the hardware. • Full Access: The attacker can reach to the lowest level of implementation abstraction on a chip—gate level. B. Resources • Limited Resources: Availability of equipment such as IC soldering/de-soldering stations, digital multimeter, universal chip programmer, prototyping boards, power supply, oscilloscope, logical analyzer and signal generator. • Moderate Resources: Availability of equipment such as laser microscope, laser interferometer navigation, infrared imaging and photomultiplier tube.
• Excessive Resources: Availability of equipment such as focused-ion beam and scanning electron microscope. C. Time • Short time: An attack that takes less than a few days to succeed. • Medium time: An attack that succeeds within weeks. • Long time: An attack that succeeds within months. D. Classification on awareness level of attack As mentioned previously, one can classify an attack according to its awareness level: Least Demanding Attack (LDA), Demanding Attack (DA) and Most Demanding Attack (MDA). Furthermore, a particular type of attack can be identified according to the level of three criteria, accessibility, resource, and resource, in order to be successful. Since we are focusing on covert attacks, more details of LDA and DA are provided in the next sections.