Research On Logic Obfuscation Technology For Hardware Security

Due to the rapid development of semiconductor technology and the increasing complex of integrated circuit(IC)design,the economic model that most semiconductor companies are based on has changed over the last decade.First,many designers cannot afford to build their own factories.As a result,the IC design and manufacture has split into two different entities.In addition,the IC design is becoming more and more complicated,reusable IP(Intelligence Property)technology can effectively alleviate the pressure of the current IC design.However,with the increasing of parties in IC design and manufacturing,ICs suffer various kinds of security problems such as IP theft,IC,IC piracy,IC overbuilding,IC reverse engineering,etc.In order to thwart these hardware security problems,researchers presented logical obfuscation techniques to protect IP/IC.The main idea is to insert additional logic gates in IP/IC design to implement logic obfuscation,IP/IC cannot run normally immediately when it be sold or produced.With the correct input to these additional gates,IC can realize the original function.Logic obfuscations can make IP/IC designers actively control of IP/IC,protect the design against hardware security issues.Focusing on the logic obfuscation technique,the main works of this paper are as follows:(1)This article proposed a novel combination logic obfuscation technique based on the 2x1 logic gate,it can reduce the high overhead of current combinational logic obfuscation techniques.The key module of the proposed obfuscation technique is the obfuscation cell which consists of two 2x1 gates and one 2x1 multiplexer,and a secret key is used to control the function of obfuscation cells.The obfuscation technique can effectively obfuscate the gate-level netlist,even if attackers can extract gate-level netlist by reverse engineering,they still cannot infer the function of digital circuit.This article prove that the time complexity to crack the key is exponential time O(2n)after reverse engineering.Based on the regular expression,this article design a program can realize logic obfuscation automatically.Experimental on the ISCAS benchmarks show that the proposed obfuscation technique is able to obfuscate the original circuits while incurs low delay,area and power overhead when avoid critical paths.(2)Based on the research of the key mechanisms in current obfuscation techniques,this article proposed a logic obfuscation key scheme based on the advantages of SRAM PUF in hardware security.The proposed key scheme can effectively guarantee the security of key,and avoided key exposures,implementation process complex,use of NVM increased the costs which the traditional key scheme suffers,and actively control the use of IC,thwart IC piracy and IC overbuilding.