Hardware Security - Week 5

1. Which of the followings added by a system designer will be considered as a hardware Trojan?

• Modify the system specification so when a specific input sequence is given, a critical component will be disabled.

2. In the example we have showed for trusted IC and hardware Trojan, the following functions are used to implement F(x)=x2:
Z1=X1
Z2=X2X3
Z3=(X1+X2)X4+X2X′3
Z4=(X2⊕X3)X4
Z5=X3X′4
Z6=0
Z7=X4
what will be the output when 11102=1410 is entered as the input? Enter your answer in binary and from Z1 to Z7.

• 1100100

3. Hardware Trojans can be functional, which will change the system's functionality, or non-functional, which do not. Non-functional hardware Trojans are also known as _________ Trojans.

• parametric

4. Which of the following statement about side channel analysis based hardware Trojan detection methods is INCORRECT?

• The errors in collecting side channel measurements do not impact the accuracy of these detection methods.

5. For two FSMs M1 and M2 and their product machine M, which of the following statements about FSM equivalence is correct?

• If M1 and M2 give different outputs for the following input 1010101010, they cannot be equivalent.  
• There is nothing special about this input. If M1 and M2 disagree on any input, they cannot be equivalent.

6. Which of the following statements about hardware Trojan prevention is true?

• Shadow registers can help to measure the delay of internal paths. So it can make the path delay based hardware Trojan detection approaches more effective.  

7. Which of the following is NOT a payload of hardware Trojan?

• Remove IC designer's watermark

8. Which of the following hardware Trojan detection methods CANNOT catch non-functional Trojans?

• Logic test based approaches

9. Which of the following approaches is a pre-synthesis hardware Trojan prevention method?

• Test and validation

10. We have shown that replacing Z2=X2X3 with Z2=(X1+X2)X3 will add a hardware Trojan to the circuit in question 2. Which of the following statements about hardware Trojan-free (or trusted IC) implementation is FALSE?

• Replacing Z6=0 by Z6=X1X3 cannot prevent the hardware Trojan showed in this question.

11. Which of the following statements about hardware Trojan detection is true (assume that the Trojan detection tool is trusted)?

• When a Trojan is reported, the IC cannot be trusted.

12. Which of the following statements about physical attacks and hardware Trojan detection approaches is FALSE?

• Physical attacks can be invasive, but hardware Trojan detection cannot.

13. A small kill switch (a 2-input AND gate and a triggering signal) is added to the chip to disable the encryption engine. Which of the following hardware Trojan detection approaches most likely will NOT be able to catch it?

• Power side channel analysis.
• Because of the small size of the Trojan and the impact of noise and variations, it is unlikely for this method to catch the kill switch.

14. Which phase in the IC supply chain is considered trusted?

• Deploy and monitor