Research On Minterm Protection Based IC Camouflaging Technology

Hardware is the root of software,networks,and information systems.However,with the increasing development of integrated circuits(ICs)and the globalization of their design and manufacturing,the security and credibility of hardware designs are suffering from various kinds of security problems such as reverse engineering,IP piracy and so on.In recent years,researchers have proposed IC camouflaging technology,which effectively resist the circuit piracy using imaging-based top-down reverse engineering.However,the security of this technology has been threatened by Boolean satisfiability(SAT)based attack.As a defense to the SAT-based de-camouflaging attack,a brand new camouflaging strategy(called CamoPerturb)has been proposed recently.This camouflaging strategy perturbs one minterm by changing one gate's functionality and then restores the perturbed circuit with a separated camouflaged block.The specific design of this separated block achieves good resistance against the SAT-based attack.In order to further improve the security of this camouflage strategy,protecting the critical signal volume of the circuit,and improving the anti-attack capability of the chip,this thesis focuses on the IC camouflaging technology,the main works are as follows:(1)This thesis analyzes the security vulnerabilities of the minterm protection based IC camouflaging technology and then proposes a novel attack method DeCamo based on the circuit structure.First,we analyze the implementation methods of this camouflaging strategy proposed by CamoPerturb.Then by leveraging sensitization and implication principles,we demonstrate the mechanism of minterm perturbation that induced by gate replacement.Next we use FAN algorithm as reference to calculate the replaced gate and perturbed minterm,thus recovering the original circuit structure.The experiments are conducted on ISCAS'89 benchmark circuits and the controllers of OpenSPARC microprocessor,and results show the efficiency of this attack technique that the CamoPerturb circuit can be de-camouflaged in a few milliseconds.(2)Based on research of this camouflaging strategy,this thesis analyzes its improvements and proposed an improved minterm protection based camouflaging technology.This technique greatly improves the output corruptibility of the circuit by changing the structure of the camouflaged module.To resist the above DeCamo attack,this technology replaces the origin gate with another circuit.This perturbed minterm optimization technique can hide the perturbed minterm and replaced gate,achieving good resistance against DeCamo attack.Experiment results show that this improved minterm protection based camouflaging technology achieves high output corruptibility and can effectively resist the attack of the de-camouflaging technology.