Study On Secure Retrieval Of PUF Information And Its Application In IC Metering Techniques

While integrated circuits(ICs)are rapidly developing and widely used in various fields,there are more and more kinds of attacks on ICs,which not only cause huge economic losses but also pose serious threats to the corresponding fields.In order to solve the damage and threat caused by chip piracy,authentication scheme is usually used to verify the legitimacy of the chip.Physical unclonable function(PUF)can exploit the unpredictable variations during IC manufacturing to generate a unique fingerprint for each chip.This enables PUF to be widely applied in various IC authentication schemes.Under some cases,the PUF response need not be protected and it is accessible to everyone,such as those authentication schemes use strong PUF which usually has exponential number of challenge response pairs(CRP).However,in other authentication scenarios,PUF,especially weak PUF which has limited CRPs,is used for the key generation and the key should be kept confidential to all but known to the chip designer or legitimate party.Otherwise,the security of overall scheme cannot be guaranteed.PUF based key overcomes the weakness in security of traditional key which stored in conventional nonvolatile memory(NVM).However,the problem of secure retrieval of PUF information has been neglected or underestimated in many application scenarios.In order to emphasize the importance of secure PUF retrieval,this dissertation determines the situation that needs secure PUF retrieval.In those schemes,where PUF is applied to them as a key in which the locked design is generated,the PUF response should be retrieved in a secure process,only by the designer or trusted party.This dissertation proposes the principle of secure PUF retrieval and discusses its evaluation criteria.Advices are given on how to choose the appropriate PUF security retrieval method for a particular hardware design.This dissertation proposes a new secure PUF retrieval scheme based on scan chain.The scheme reuses the scan chain structure in the original design and adds some logics around the scan cells of the original scan chain,thereby obfuscating PUF response with the added logic.The correct PUF response can be inferred from the obfuscated results only by the designer who has the knowledge of modified design.Then this paper evaluates the testability,security,and overhead of the proposed scheme and compares it with other existing PUF retrieval scenarios.The scheme has no impact on testing and normal operation of the original design.It is resistant to known attacks.Compared with the encryption based PUF retrieval scheme,this scheme has higher security and is interwoven with the original function.It is difficult for an attacker to distinguish between the original design and the retrieval design to bypass the PUF retrieval structure.For a 128-bit PUF,the area overhead of the design is only equivalent to 495 NAND gates,which is much less than the overhead of encryption based schemes.Based on the proposed secure PUF retrieval scheme above,a new external active IC metering scheme is proposed.IC metering is a protocol to enable designers control and monitor each IC after manufacturing that can effectively solve IC piracy and overbuilding problems.The external active IC metering scheme proposed in this paper mainly includes four parts,PUF generation,logic obfuscation,PUF retrieval and controller.In IC metering,as a structure for producing unique ID,PUF needs to be an ideal design with perfect reliability.The proposed scheme adopts the VIA PUF which has perfect reliability,avoiding using error correcting code(ECC)that reduces huge overhead.Unlike previous IC metering schemes that add lock on combinational logic,this scheme first proposes sequential logic lock in circuits to realize data obfuscation.In this scheme,PUF retrieval are interwoven with sequential logic lock and original function,which not only reduces the area overhead of the overall design,but also avoids the possibility that the protection mechanism of the PUF is bypassed.According to the PUF response and unlocking information,the designer can deduce the unique key for each chip to unlock the normal function of the.The solution is evaluated in the tsmc0.18 technology library.Compared with the external IC metering scheme based on encryption module,the overhead of proposed scheme is only equivalent to 8012 two-input NAND gates under 100% reliability.