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[Anonymous].  2021.  Secure Hardware Design: Starting from the Roots of Trust. 2021 IEEE European Test Symposium (ETS). :i—i.
Summary form only given, as follows. The complete presentation was not made available for publication as part of the conference proceedings. What is “hardware” security? The network designer relies on the security of the router box. The software developer relies on the TPM (Trusted Platform Module). The circuit designer worries about side-channel attacks. At the same time, electronics shrink: sensor nodes, IOT devices, smart devices are becoming more and more available. Adding security and cryptography to these often very resource constraint devices is a challenge. This presentation will focus on Physically Unclonable Functions and True Random Number Generators, two roots of trust, and their security testing.
Hasan Anik, Toufiq, Danger, Jean-Luc, Diankha, Omar, Ebrahimabadi, Mohammad, Frisch, Christoph, Guilley, Sylvain, Karimi, Naghmeh, Pehl, Michael, Takarabt, Sofiane.  2021.  Testing and Reliability Enhancement of Security Primitives. 2021 IEEE International Symposium on Defect and Fault Tolerance in VLSI and Nanotechnology Systems (DFT). :1–8.
The test of security primitives is particularly strategic as any bias coming from the implementation or environment can wreck havoc on the security it is intended to provide. This paper presents how some security properties are tested on leading primitives: True Random Number Generation (TRNG), Physically Unclonable Function (PUF), cryptographic primitives and Digital Sensor (DS). The test of TRNG and PUF to ensure a high level of security is mainly about the entropy assessment, which requires specific statistical tests. The security against side-channel analysis (SCA) of cryptographic primitives, like the substitution box in symmetric cryptography, is generally ensured by masking. But the hardware implementation of masking can be damaged by glitches, which create leakages on sensitive variables. A test method is to search for nets of the cryptographic netlist, which are vulnerable to glitches. The DS is an efficient primitive to detect disturbances and rise alarms in case of fault injection attack (FIA). The dimensioning of this primitive requires a precise test to take into account the environment variations including the aging.
Kroeger, Trevor, Cheng, Wei, Guilley, Sylvain, Danger, Jean-Luc, Karimi, Nazhmeh.  2021.  Making Obfuscated PUFs Secure Against Power Side-Channel Based Modeling Attacks. 2021 Design, Automation Test in Europe Conference Exhibition (DATE). :1000–1005.
To enhance the security of digital circuits, there is often a desire to dynamically generate, rather than statically store, random values used for identification and authentication purposes. Physically Unclonable Functions (PUFs) provide the means to realize this feature in an efficient and reliable way by utilizing commonly overlooked process variations that unintentionally occur during the manufacturing of integrated circuits (ICs) due to the imperfection of fabrication process. When given a challenge, PUFs produce a unique response. However, PUFs have been found to be vulnerable to modeling attacks where by using a set of collected challenge response pairs (CRPs) and training a machine learning model, the response can be predicted for unseen challenges. To combat this vulnerability, researchers have proposed techniques such as Challenge Obfuscation. However, as shown in this paper, this technique can be compromised via modeling the PUF's power side-channel. We first show the vulnerability of a state-of-the-art Challenge Obfuscated PUF (CO-PUF) against power analysis attacks by presenting our attack results on the targeted CO-PUF. Then we propose two countermeasures, as well as their hybrid version, that when applied to the CO-PUFs make them resilient against power side-channel based modeling attacks. We also provide some insights on the proper design metrics required to be taken when implementing these mitigations. Our simulation results show the high success of our attack in compromising the original Challenge Obfuscated PUFs (success rate textgreater 98%) as well as the significant improvement on resilience of the obfuscated PUFs against power side-channel based modeling when equipped with our countermeasures.
Babaei, Armin.  2021.  Lightweight and Reconfigurable Security Architecture for Internet of Things devices. 2021 IEEE International Conference on Autonomic Computing and Self-Organizing Systems Companion (ACSOS-C). :307—309.
Assuring Cybersecurity for the Internet of things (IoT) remains a significant challenge. Most IoT devices have minimal computational power and should be secured with lightweight security techniques (optimized computation and energy tradeoff). Furthermore, IoT devices are mainly designed to have long lifetimes (e.g., 10–15 years), forcing the designers to open the system for possible future updates. Here, we developed a lightweight and reconfigurable security architecture for IoT devices. Our research goal is to create a simple authentication protocol based on physical unclonable function (PUF) for FPGA-based IoT devices. The main challenge toward realization of this protocol is to make it make it resilient against machine learning attacks and it shall not use cryptography primitives.
Urien, Pascal.  2021.  Innovative Countermeasures to Defeat Cyber Attacks Against Blockchain Wallets. 2021 5th Cyber Security in Networking Conference (CSNet). :49–54.
Blockchain transactions are signed by private keys. Secure key storage and tamper resistant computing, are critical requirements for deployments of trusted infrastructure. In this paper we identify some threats against blockchain wallets, and we introduce a set of physical and logical countermeasures in order to defeat them. We introduce open software and hardware architectures based on secure elements, which enable detection of cloned device and corrupted software. These technologies are based on resistant computing (javacard), smartcard anti cloning, smartcard self content attestation, applicative firewall, bare metal architecture, remote attestation, dynamic PUF (Physical Unclonable Function), and programming token as root of trust.
Ebrahimabadi, Mohammad, Younis, Mohamed, Lalouani, Wassila, Karimi, Naghmeh.  2021.  A Novel Modeling-Attack Resilient Arbiter-PUF Design. 2021 34th International Conference on VLSI Design and 2021 20th International Conference on Embedded Systems (VLSID). :123–128.
Physically Unclonable Functions (PUFs) have been considered as promising lightweight primitives for random number generation and device authentication. Thanks to the imperfections occurring during the fabrication process of integrated circuits, each PUF generates a unique signature which can be used for chip identification. Although supposed to be unclonable, PUFs have been shown to be vulnerable to modeling attacks where a set of collected challenge response pairs are used for training a machine learning model to predict the PUF response to unseen challenges. Challenge obfuscation has been proposed to tackle the modeling attacks in recent years. However, knowing the obfuscation algorithm can help the adversary to model the PUF. This paper proposes a modeling-resilient arbiter-PUF architecture that benefits from the randomness provided by PUFs in concealing the obfuscation scheme. The experimental results confirm the effectiveness of the proposed structure in countering PUF modeling attacks.
Takemoto, Shu, Shibagaki, Kazuya, Nozaki, Yusuke, Yoshikawa, Masaya.  2020.  Deep Learning Based Attack for AI Oriented Authentication Module. 2020 35th International Technical Conference on Circuits/Systems, Computers and Communications (ITC-CSCC). :5–8.
Neural Network Physical Unclonable Function (NN-PUF) has been proposed for the secure implementation of Edge AI. This study evaluates the tamper resistance of NN-PUF against machine learning attacks. The machine learning attack in this study learns CPRs using deep learning. As a result of the evaluation experiment, the machine learning attack predicted about 82% for CRPs. Therefore, this study revealed that NN-PUF is vulnerable to machine learning attacks.
Wu, Qiang, Zhang, Jiliang.  2020.  CT PUF: Configurable Tristate PUF against Machine Learning Attacks. 2020 IEEE International Symposium on Circuits and Systems (ISCAS). :1–5.
Strong physical unclonable function (PUF) is a promising lightweight hardware security primitive for device authentication. However, it is vulnerable to machine learning attacks. This paper demonstrates that even a recently proposed dual-mode PUF is still can be broken. In order to improve the security, this paper proposes a highly flexible machine learning resistant configurable tristate (CT) PUF which utilizes the response generated in the working state of Arbiter PUF to XOR the challenge input and response output of other two working states (ring oscillator (RO) PUF and bitable ring (BR) PUF). The proposed CT PUF is implemented on Xilinx Artix-7 FPGAs and the experiment results show that the modeling accuracy of logistic regression and artificial neural network is reduced to the mid-50%.
Zhang, Yan, Li, Bing, Wang, Yazhou, Wu, Jiaxin, Yuan, Pengwei.  2020.  A Blockchain-based User Remote Autentication Scheme in IoT Systems Using Physical Unclonable Functions. 2020 IEEE 5th International Conference on Signal and Image Processing (ICSIP). :1100—1105.
Achieving efficient and secure accesses to real-time information from the designated IoT node is the fundamental key requirement for the applications of the Internet of Things. However, IoT nodes are prone to physical attacks, public channels reveal the sensitive information, and gateways that manage the IoT nodes suffer from the single-point failure, thereby causing the security and privacy problems. In this paper, a blockchain-based user remote authentication scheme using physical unclonable functions (PUFs) is proposed to overcome these problems. The PUFs provide physically secure identities for the IoT nodes and the blockchain acts as a distributed database to manage the key materials reliably for gateways. The security analysis is conducted and shows that our scheme realizes reliable security features and resists various attacks. Furthermore, a prototype was implemented to prove our scheme is efficient, scalable, and suitable for IoT scenarios.
Latha Ch., Mary, Bazil Raj, A.A., Abhikshit, L..  2020.  Design and Implementation of a Secure Physical Unclonable Function In FPGA. 2020 Second International Conference on Inventive Research in Computing Applications (ICIRCA). :1083–1089.
A Field Programmable Gate Array (FPGA) is a digital Integrated Circuit made up of interconnected functional blocks, which can be programmed by the end-user to perform required logic functions. As FPGAs are re-programmable, partially re-configurable and have lowertime to market, FPGA has become a vital component in the field of electronics. FPGAs are undergoing many security issues as the adversaries are trying to make profits by replicating the original design, without any investment. The major security issues are cloning, counterfeiting, reverse engineering, Physical tampering, and insertion of malicious components, etc. So, there is a need for security of FPGAs. A Secret key must be embedded in an IC, to provide identification and authentication to it. Physical Unclonable Functions (PUFs) can provide these secret keys, by using the physical properties of the chip. These physical properties are not reproducible even by the manufacturer. Hence the responses produced by the PUF are unique for every individual chip. The method of generating unique binary signatures helps in cryptographic key generation, digital rights management, Intellectual Property (IP) protection, IC counterfeit prevention, and device authentication. The PUFs are very promising in signature generation in the field of hardware security. In this paper, the secret binary responses is generated with the help of a delay based Ring Oscillator PUF, which does not use a clock circuit in its architecture.
Mehndiratta, Nishtha.  2020.  A Yoking-Proof and PUF-based Mutual Authentication Scheme for Cloud-aided Wearable Devices. 2020 IEEE International Conference for Innovation in Technology (INOCON). :1—4.

In today's world privacy is paramount in everyone's life. Alongside the growth of IoT (Internet of things), wearable devices are becoming widely popular for real-time user monitoring and wise service support. However, in contrast with the traditional short-range communications, these resource-scanty devices face various vulnerabilities and security threats during the course of interactions. Hence, designing a security solution for these devices while dealing with the limited communication and computation capabilities is a challenging task. In this work, PUF (Physical Unclonable Function) and lightweight cryptographic parameters are used together for performing two-way authentication between wearable devices and smartphone, while the simultaneous verification is performed by providing yoking-proofs to the Cloud Server. At the end, it is shown that the proposed scheme satisfies many security aspects and is flexible as well as lightweight.

Zerrouki, F., Ouchani, S., Bouarfa, H..  2020.  Quantifying Security and Performance of Physical Unclonable Functions. 2020 7th International Conference on Internet of Things: Systems, Management and Security (IOTSMS). :1—4.

Physical Unclonable Function is an innovative hardware security primitives that exploit the physical characteristics of a physical object to generate a unique identifier, which play the role of the object's fingerprint. Silicon PUF, a popular type of PUFs, exploits the variation in the manufacturing process of integrated circuits (ICs). It needs an input called challenge to generate the response as an output. In addition, of classical attacks, PUFs are vulnerable to physical and modeling attacks. The performance of the PUFs is measured by several metrics like reliability, uniqueness and uniformity. So as an evidence, the main goal is to provide a complete tool that checks the strength and quantifies the performance of a given physical unconscionable function. This paper provides a tool and develops a set of metrics that can achieve safely the proposed goal.

Zheng, Y., Cao, Y., Chang, C..  2020.  A PUF-Based Data-Device Hash for Tampered Image Detection and Source Camera Identification. IEEE Transactions on Information Forensics and Security. 15:620—634.
With the increasing prevalent of digital devices and their abuse for digital content creation, forgeries of digital images and video footage are more rampant than ever. Digital forensics is challenged into seeking advanced technologies for forgery content detection and acquisition device identification. Unfortunately, existing solutions that address image tampering problems fail to identify the device that produces the images or footage while techniques that can identify the camera is incapable of locating the tampered content of its captured images. In this paper, a new perceptual data-device hash is proposed to locate maliciously tampered image regions and identify the source camera of the received image data as a non-repudiable attestation in digital forensics. The presented image may have been either tampered or gone through benign content preserving geometric transforms or image processing operations. The proposed image hash is generated by projecting the invariant image features into a physical unclonable function (PUF)-defined Bernoulli random space. The tamper-resistant random PUF response is unique for each camera and can only be generated upon triggered by a challenge, which is provided by the image acquisition timestamp. The proposed hash is evaluated on the modified CASIA database and CMOS image sensor-based PUF simulated using 180 nm TSMC technology. It achieves a high tamper detection rate of 95.42% with the regions of tampered content successfully located, a good authentication performance of above 98.5% against standard content-preserving manipulations, and 96.25% and 90.42%, respectively, for the more challenging geometric transformations of rotation (0 360°) and scaling (scale factor in each dimension: 0.5). It is demonstrated to be able to identify the source camera with 100% accuracy and is secure against attacks on PUF.
Riya, S. S., Lalu, V..  2020.  Stable cryptographic key generation using SRAM based Physical Unclonable Function. 2020 International Conference on Smart Electronics and Communication (ICOSEC). :653—657.
Physical unclonable functions(PUFs) are widely used as hardware root-of-trust to secure IoT devices, data and services. A PUF exploits inherent randomness introduced during manufacturing to give a unique digital fingerprint. Static Random-Access Memory (SRAM) based PUFs can be used as a mature technology for authentication. An SRAM with a number of SRAM cells gives an unrepeatable and random pattern of 0's and 1's during power on. As it is a unique pattern, it can be called as SRAM fingerprint and can be used as a PUF. The chance of producing more number of same values (either zero or one) is higher during power on. If a particular value present at almost all the cell during power on, it will lead to the dominance of either zero or one in the cryptographic key sequence. As the cryptographic key is generated by randomly taking address location of SRAM cells, (the subset of power on values of all the SRAM cells)the probability of occurring the same sequence most of the time is higher. In order to avoid that situation, SRAM should have to produce an equal number of zeros and ones during power on. SRAM PUF is implemented in Cadence Virtuoso tool. To generate equal zeros and ones during power on, variations can be done in the physical dimensions and to increase the stability body biasing can be effectively done.
Mobaraki, S., Amirkhani, A., Atani, R. E..  2018.  A Novel PUF based Logic Encryption Technique to Prevent SAT Attacks and Trojan Insertion. 2018 9th International Symposium on Telecommunications (IST). :507–513.
The manufacturing of integrated circuits (IC) outside of the design houses makes it possible for the adversary to easily perform a reverse engineering attack against intellectual property (IP)/IC. The aim of this attack can be the IP piracy, overproduction, counterfeiting or inserting hardware Trojan (HT) throughout the supply chain of the IC. Preventing hardware Trojan insertion is a significant issue in the context of hardware security (HS) and has not been considered in most of the previous logic encryption methods. To eliminate this problem, in this paper an Anti-Trojan insertion algorithm is presented. The idea is based on the fact that reducing the signals with low-observability (LO) and low-controllability (LC) can prevent HT insertion significantly. The security of logic encryption methods depends on the algorithm and the encryption key. However, the security of these methods has been compromised by SAT attacks over recent years. SAT attacks, can decode the correct key from most logic encryption techniques. In this article, by using the PUF-based encryption, the applied key in the encryption is randomized and SAT attack cannot be performed. Based on the output of PUF, a unique encryption has been made for each chip that preventing from counterfeiting and IP piracy.
Zhang, Jiliang, Qu, Gang.  2020.  Physical Unclonable Function-Based Key Sharing via Machine Learning for IoT Security. IEEE Transactions on Industrial Electronics. 67:7025—7033.

In many industry Internet of Things applications, resources like CPU, memory, and battery power are limited and cannot afford the classic cryptographic security solutions. Silicon physical unclonable function (PUF) is a lightweight security primitive that exploits manufacturing variations during the chip fabrication process for key generation and/or device authentication. However, traditional weak PUFs such as ring oscillator (RO) PUF generate chip-unique key for each device, which restricts their application in security protocols where the same key is required to be shared in resource-constrained devices. In this article, in order to address this issue, we propose a PUF-based key sharing method for the first time. The basic idea is to implement one-to-one input-output mapping with lookup table (LUT)-based interstage crossing structures in each level of inverters of RO PUF. Individual customization on configuration bits of interstage crossing structure and different RO selections with challenges bring high flexibility. Therefore, with the flexible configuration of interstage crossing structures and challenges, crossover RO PUF can generate the same shared key for resource-constrained devices, which enables a new application for lightweight key sharing protocols.

Sun, Peiqi, Cui, Aijiao.  2019.  A New Pay-Per-Use Scheme for the Protection of FPGA IP. 2019 IEEE International Symposium on Circuits and Systems (ISCAS). :1—5.
Field-programmable gate arrays (FPGAs) are widely applied in various fields for its merit of reconfigurability. The reusable intellectual property (IP) design blocks are usually adopted in the more complex FPGA designs to shorten design cycle. IP infringement hence becomes a concern. In this paper, we propose a new pay-per-use scheme using the lock and key mechanism for the protection of FPGA IP. Physical Unclonable Function (PUF) is adopted to generate a unique ID for each IP instance. An extra Finite State Machine (FSM) is introduced for the secure retrieval of PUF information by the FPGA IP vendor. The lock is implemented on the original FSM. Only when the FPGA developer can provide a correct license, can the FSM be unlocked and start normal operation. The FPGA IP can hence be protected from illegal use or distribution. The scheme is applied on some benchmarks and the experimental results show that it just incurs acceptably low overhead while it can resist typical attacks.
Nozaki, Yusuke, Yoshikawa, Masaya.  2019.  Countermeasure of Lightweight Physical Unclonable Function Against Side-Channel Attack. 2019 Cybersecurity and Cyberforensics Conference (CCC). :30–34.

In industrial internet of things, various devices are connected to external internet. For the connected devices, the authentication is very important in the viewpoint of security; therefore, physical unclonable functions (PUFs) have attracted attention as authentication techniques. On the other hand, the risk of modeling attacks on PUFs, which clone the function of PUFs mathematically, is pointed out. Therefore, a resistant-PUF such as a lightweight PUF has been proposed. However, new analytical methods (side-channel attacks: SCAs), which use side-channel information such as power or electromagnetic waves, have been proposed. The countermeasure method has also been proposed; however, an evaluation using actual devices has not been studied. Since PUFs use small production variations, the implementation evaluation is very important. Therefore, this study proposes a SCA countermeasure of the lightweight PUF. The proposed method is based on the previous studies, and maintains power consumption consistency during the generation of response. In experiments using a field programmable gate array, the measured power consumption was constant regardless of output values of the PUF could be confirmed. Then, experimental results showed that the predicted rate of the response was about 50 %, and the proposed method had a tamper resistance against SCAs.

Jiang, Qi, Zhang, Xin, Zhang, Ning, Tian, Youliang, Ma, Xindi, Ma, Jianfeng.  2019.  Two-Factor Authentication Protocol Using Physical Unclonable Function for IoV. 2019 IEEE/CIC International Conference on Communications in China (ICCC). :195–200.
As an extension of Internet of Things (IoT) in transportation sector, the Internet of Vehicles (IoV) can greatly facilitate vehicle management and route planning. With ever-increasing penetration of IoV, the security and privacy of driving data should be guaranteed. Moreover, since vehicles are often left unattended with minimum human interventions, the onboard sensors are vulnerable to physical attacks. Therefore, the physically secure authentication and key agreement (AKA) protocol is urgently needed for IoV to implement access control and information protection. In this paper, physical unclonable function (PUF) is introduced in the AKA protocol to ensure that the system is secure even if the user devices or sensors are compromised. Specifically, PUF, as a hardware fingerprint generator, eliminates the storage of any secret information in user devices or vehicle sensors. By combining password with PUF, the user device cannot be used by someone else to be successfully authenticated as the user. By resorting to public key cryptography, the proposed protocol can provide anonymity and desynchronization resilience. Finally, the elaborate security analysis demonstrates that the proposed protocol is free from the influence of known attacks and can achieve expected security properties, and the performance evaluation indicates the efficiency of our protocol.
Liu, Donglan, Liu, Xin, Zhang, Hao, Yu, Hao, Wang, Wenting, Ma, Lei, Chen, Jianfei, Li, Dong.  2019.  Research on End-to-End Security Authentication Protocol of NB-IoT for Smart Grid Based on Physical Unclonable Function. 2019 IEEE 11th International Conference on Communication Software and Networks (ICCSN). :239–244.
As a national strategic hot spot, the Internet of Things (IoT) has shown its vigor and vitality. With the development of IoT, its application in power grid is more and more extensive. As an advanced technology for information sensing and transmission, IoT has been applied extensively in power generation, transmission, transformation, distribution, utilization and other processes, and will develop with broad prospect in smart grid. Narrow Band Internet of Things (NB-IoT) is of broad application prospects in production management, life-cycle asset management and smart power utilization of smart grid. Its characteristics and security demands of application domain present a challenge for the security of electric power business. However, current protocols either need dual authentication and key agreements, or have poor compatibility with current network architecture. In order to improve the high security of power network data transmission, an end-to-end security authentication protocol of NB-IoT for smart grid based on physical unclonable function and state secret algorithm SM3 is proposed in this paper. A self-controllable NB-IoT application layer security architecture was designed by introducing the domestic cryptographic algorithm, extending the existing key derivation structure of LTE, and combining the physical unclonable function to ensure the generation of encryption keys between NB-IoT terminals and power grid business platforms. The protocol of this paper realizes secure data transmission and bidirectional identity authentication between IoT devices and terminals. It is of low communication costs, lightweight and flexible key update. In addition, the protocol also supports terminal authentication during key agreement, which furtherly enhances the security of business systems in smart grid.
Nozaki, Yusuke, Yoshikawa, Masaya.  2018.  Area Constraint Aware Physical Unclonable Function for Intelligence Module. 2018 3rd International Conference on Computational Intelligence and Applications (ICCIA). :205-209.

Artificial intelligence technology such as neural network (NN) is widely used in intelligence module for Internet of Things (IoT). On the other hand, the risk of illegal attacks for IoT devices is pointed out; therefore, security countermeasures such as an authentication are very important. In the field of hardware security, the physical unclonable functions (PUFs) have been attracted attention as authentication techniques to prevent the semiconductor counterfeits. However, implementation of the dedicated hardware for both of NN and PUF increases circuit area. Therefore, this study proposes a new area constraint aware PUF for intelligence module. The proposed PUF utilizes the propagation delay time from input layer to output layer of NN. To share component for operation, the proposed PUF reduces the circuit area. Experiments using a field programmable gate array evaluate circuit area and PUF performance. In the result of circuit area, the proposed PUF was smaller than the conventional PUFs was showed. Then, in the PUF performance evaluation, for steadiness, diffuseness, and uniqueness, favorable results were obtained.

Nozaki, Yusuke, Yoshikawa, Masaya.  2018.  EM Based Machine Learning Attack for XOR Arbiter PUF. Proceedings of the 2Nd International Conference on Machine Learning and Soft Computing. :19-23.

The physical unclonable functions (PUFs) have been attracted attention to prevent semiconductor counterfeits. However, the risk of machine learning attack for an arbiter PUF, which is one of the typical PUFs, has been reported. Therefore, an XOR arbiter PUF, which has a resistance against the machine learning attack, was proposed. However, in recent years, a new machine learning attack using power consumption during the operation of the PUF circuit was reported. Also, it is important that the detailed tamper resistance verification of the PUFs to consider the security of the PUFs in the future. Therefore, this study proposes a new machine learning attack using electromagnetic waveforms for the XOR arbiter PUF. Experiments by an actual device evaluate the validity of the proposed method and the security of the XOR arbiter PUF.

Moghadas, S. H., Fischer, G..  2017.  Robust IoT communication physical layer concept with improved physical unclonable function. 2017 IEEE Asia Pacific Conference on Postgraduate Research in Microelectronics and Electronics (PrimeAsia). :97–100.

Reliability and robustness of Internet of Things (IoT)-cloud-based communication is an important issue for prospective development of the IoT concept. In this regard, a robust and unique client-to-cloud communication physical layer is required. Physical Unclonable Function (PUF) is regarded as a suitable physics-based random identification hardware, but suffers from reliability problems. In this paper, we propose novel hardware concepts and furthermore an analysis method in CMOS technology to improve the hardware-based robustness of the generated PUF word from its first point of generation to the last cloud-interfacing point in a client. Moreover, we present a spectral analysis for an inexpensive high-yield implementation in a 65nm generation. We also offer robust monitoring concepts for the PUF-interfacing communication physical layer hardware.

Liu, M., Zhou, C., Tang, Q., Parhi, K. K., Kim, C. H..  2017.  A data remanence based approach to generate 100% stable keys from an SRAM physical unclonable function. 2017 IEEE/ACM International Symposium on Low Power Electronics and Design (ISLPED). :1–6.

The start-up value of an SRAM cell is unique, random, and unclonable as it is determined by the inherent process mismatch between transistors. These properties make SRAM an attractive circuit for generating encryption keys. The primary challenge for SRAM based key generation, however, is the poor stability when the circuit is subject to random noise, temperature and voltage changes, and device aging. Temporal majority voting (TMV) and bit masking were used in previous works to identify and store the location of unstable or marginally stable SRAM cells. However, TMV requires a long test time and significant hardware resources. In addition, the number of repetitive power-ups required to find the most stable cells is prohibitively high. To overcome the shortcomings of TMV, we propose a novel data remanence based technique to detect SRAM cells with the highest stability for reliable key generation. This approach requires only two remanence tests: writing `1' (or `0') to the entire array and momentarily shutting down the power until a few cells flip. We exploit the fact that the cells that are easily flipped are the most robust cells when written with the opposite data. The proposed method is more effective in finding the most stable cells in a large SRAM array than a TMV scheme with 1,000 power-up tests. Experimental studies show that the 256-bit key generated from a 512 kbit SRAM using the proposed data remanence method is 100% stable under different temperatures, power ramp up times, and device aging.

Nozaki, Yusuke, Yoshikawa, Masaya.  2017.  Tamper Resistance Evaluation of PUF Implementation Against Machine Learning Attack. Proceedings of the 2017 International Conference on Biometrics Engineering and Application. :1–6.
Recently, the semiconductor counterfeiting has become a serious problem. To counter this problem, Physical Unclonable Function (PUF) has been attracted attention. However, the risk of machine learning attacks for PUF is pointed out. To verify the safety of PUF, the evaluation (tamper resistance) against machine learning attacks in the difference of PUF implementations is very important. However, the tamper resistance evaluation in the difference of PUF implementation has barely been reported. Therefore, this study evaluates the tamper resistance of PUF in the difference of field programmable gate array (FPGA) implementations against machine learning attacks. Experiments using an FPGA clarified the arbiter PUF of the lookup table implementation has the tamper resistance against machine learning attacks.