Gate level obfuscation using programable contacts is one of the techniques used for obfuscating the netlist to defend against netlist reverse engineering. Using this technique, a designer implements obfuscation so that it is not clear to the attacker whether the obfuscated gate G1 is XOR, NOR, or NAND during netlist reverse engineering. During the netlist reverse engineering process, the attacker places a placeholder G1 and measures the output O with various the input vectors I1,I2,I3,I4,I5 for a working IC obtained from open market. Using this technique, the attacher tries to resolve if G1 is XOR, NOR, or NAND gate. The attacker observes O=1 for input I1,I2,I3,I4,I5={0,0,0,0,0}. This observation eliminates the possibility that G1 is:
Exam2-Obfuscation-1-Fig.png
Group of answer choices
NAND
XOR
NOR
Cannot resolve