AN EFFICIENT HOMOMORPHIC ENCRYPTION AND PUF AUTHENTICATION WITH SWO-QBFT CONSENSUS ALGORITHM FOR SECURE SMART GRID INFRASTRUCTURE

The use of physically unclonable functions (PUFs) as a new cryptographic technique is gaining attention. Challenge-response authentication and key generation (key storage) are well known as major applications using PUFs. When PUFs are applied to these applications, min-entropy estimation is essential. The min-entropy is a measure of the lower bound of the unpredictability of PUF responses. Many studies have estimated the min-entropy of PUFs, and several of these studies dealt with PUFs with independent and identically distributed (IID) PUF responses. Few studies have focused on non-IID PUFs. One reason is that some causes of entropy loss are complicatedly intertwined, and the entropy estimation of non-IID PUFs is hard. Thus, it is first necessary to break down the intertwined causes to estimate min-entropy. In this paper, we present typical causes of entropy loss during PUF implementation and propose a cause analysis method using the Inter-Hamming distance (HD), which is one of major performance metrics of PUFs. And the proposed method was applied to prototyped PUFs designed with a 180-nm CMOS process. We demonstrate that the causes of entropy loss on each PUF can be broken down according to the analysis results.

Field-programmable gate arrays (FPGAs) have firmly established themselves as dynamic platforms for the implementation of physical unclonable functions (PUFs). Their intrinsic reconfigurability and profound implications for enhancing hardware security make them an invaluable asset in this realm. This groundbreaking study not only dives deep into the universe of FPGA-based PUF designs but also offers a comprehensive overview coupled with a discerning comparative analysis. PUFs are the bedrock of device authentication and key generation and the fortification of secure cryptographic protocols. Unleashing the potential of FPGA technology expands the horizons of PUF integration across diverse hardware systems. We set out to understand the fundamental ideas behind PUF and how crucially important it is to current security paradigms. Different FPGA-based PUF solutions, including static, dynamic, and hybrid systems, are closely examined. Each design paradigm is painstakingly examined to reveal its special qualities, functional nuances, and weaknesses. We closely assess a variety of performance metrics, including those related to distinctiveness, reliability, and resilience against hostile threats. We compare various FPGA-based PUF systems against one another to expose their unique advantages and disadvantages. This study provides system designers and security professionals with the crucial information they need to choose the best PUF design for their particular applications. Our paper provides a comprehensive view of the functionality, security capabilities, and prospective applications of FPGA-based PUF systems. The depth of knowledge gained from this research advances the field of hardware security, enabling security practitioners, researchers, and designers to make wise decisions when deciding on and implementing FPGA-based PUF solutions.

A Physical Unclonable Function (PUF) is a die specific random function that can be used in a number of secure IC applications including die identification/authentication and key generation. At the core of a silicon PUF is a circuit (the PUF core) that generates random bits. These bits are like a silicon biometric, unique across dies, but can be reliably reproduced multiple times on a die across voltage and temperature variations and aging. In this thesis, we discuss various aspects of a PUF design, with a strong focus on circuit details. We describe the properties and the figures of merit of a PUF and then compare various PUF core implementations. We identify the biggest design challenges and provide several solutions. Results in this work are supported by measurement data from testchips designed in 65nm bulk CMOS. We provide an apples-to-apples comparison of various PUF implementations. We demonstrate that while adequate randomness and uniqueness is achievable for most PUF implementations, achieving high reliability is a challenge. The conventional method to achieve high reliability is to use error correcting codes (ECC). Unfortunately, the overheads associated with these techniques grows very quickly with error correction capability. Alternately, researchers have proposed several error reduction techniques to minimize the use of error correction. In this work, we evaluate four orthogonal and complementary error reduction techniques. Two of these techniques, categorized as extrinsic techniques, are multiple evaluation (ME) and activation control (AC) and are able to reduce errors in PUF response by ~70-80%. The other two techniques, categorized as intrinsic, are post-silicon selection (PSS) and directed accelerated aging (DAA) and show ~100% correction of errors. As a proof of concept prototype, we describe a self-contained, BIST-controlled key-generator that implements the PSS technique to autonomously generate bits with a bit error rate < 5 * 10^-9, equivalent to a 128-bit key error rate < 10^-6. We also describe a realization of a strong-PUF that uses these highly reliable bits in conjunction with an Advanced Encryption Standard (AES) primitive.

Recent fourth industrial revolution, industry4.0 results in lot of automation of industrial processes and brings intelligence in many home appliances in the form of IoT, enhances M2M / D2D communication where electronic devices play a prominent role. It is very much necessary to ensure security of those devices. To provide reliable authentication and identification of each device and to abort the counterfeiting from the unauthorized foundries Physical Unclonable Functions (PUFs) emerged as a one of the promising cryptographic hardware security solution. PUF is function, mathematically modeled by using uncontrollable/ unavoidable random variances of the fabrication process of the ICs. These variances can generate unpredictable, random responses can be used to overcome the difficulties such as storing the keys in non-volatile memories (NVMs) in the classical cryptography. A wide variety of PUF architectures such as Arbiter PUFs, Ring oscillator PUFs, SRAM PUFs proposed by authors. But due to its design complexity and low cost, Delay based Arbiter PUFs (D-PUFs) are considering to be a one of the security primitives in authentication applications such as low-cost IoT devices for secure key generation. This paper presents a review on the different types of Delay based PUF architectures proposed by the various authors, sources to exhibit the physical disorders in ICs, methods to estimate the Performance metrics and applications of PUF in different domains.

The Physically Unclonable Function (PUF), which extracts a unique device identification based on variations in manufacturing processes, has recently attracted attention. IoT devices, including sensor monitors and wearables, have come into widespread use, and various kinds of devices have access to a range of services. Device authentication and management of key to encryption communication data are essential for a secure service. We can realize secure authentication based on device identification extracted by a PUF. For example, PUF is used as a key generator to avoid storing the encryption key in a device. However, existing PUFs require dedicated hardware or software (driver) to extract device identification. Thus, it may not be possible to apply existing PUFs to IoT devices in a situation where there are a variety of devices and many device manufacturers. We can use characteristic values of existing sensors in an IoT device as an alternative to PUF. In this paper, we expand an existing software PUF based to support characteristic values extract from a gyroscope, and evaluate the entropy and robustness. We found that the same device identifier can be reliably extracted from a gyroscope even under conditions of high and low temperature, and low-pressure. No changes in the characteristic values of the gyroscope due to degradation with age were found over a wearing period exceeding than three years. The device identifier has up to 81.2 bits entropy with no error-correcting mechanism. It has up to 57.7 bits entropy when error-correction of one bit is applied to each characteristic value by a Fuzzy extractor.

Physical unclonable functions (PUFs) are primitives that generate high-entropy, tamper resistant bits for use in secure systems. For applications such as cryptographic key generation, the PUF response bits must be highly reliable, consistent across multiple evaluations under voltage and temperature variations. Conventionally, error correcting codes (ECC) have been used to improve response reliability, but these techniques have significant area, power, and delay overheads and are vulnerable to information leakage. In this work, we present a highly-reliable, PUF-based, cryptographic key generator that uses no ECC, but instead uses built-in self-test to determine which PUF bits are reliable and only uses those bits for key generation. We implemented a prototype of the key generator in a 65nm bulk CMOS testchip. The key generator generates 1213 bits in an area of <;50k/μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with a measured bit error rate of <; 5 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">*</sub> 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-9</sup> in both the nominal and worst case corners (100k measurements each). This is equivalent to a 128-bit key failure rate of <; 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-6</sup> . The system can generate a 128-bit key in 1.15μs. Finally, we present a realization of a “strong”-PUF that uses 128 of these highly reliable bits in conjunction with an Advanced Encryption Standard (AES) cryptographic primitive and has a response time of 40ns and is realized in an area of 84k/μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Cloud computing technologies comprise various kinds of significant desirable constrains such as security, liability, government surveillance, telecommunications capacity, anonymity and privacy. The usage of cipher text technology is considered as a desired technique for performing the process of encryption in order to solve the issue of granting security to the data that are shared in the cloud. Similarly, the architecture of multi-tenant in the cloud computing system grants benefits to both the service providers and end-users which shares a common cloud platform to multiple tenants (i.e.) users and suitable resources are also computed by implementing proposed architecture. Therefore in this research work, the concept of cipher text multi-tenant are integrated for providing enhanced security to the data shared in the cloud environment. Hence a Modified Elliptic Curve Cryptography (MECC) based on Diffee Hellman algorithm is proposed in this research paper which provides enhanced security using alternate key generation. The encryption, decryption, upload and download time are calculated and it is concluded that the algorithm that is proposed in this research paper consumes less time for all these measures when comparing with other existing algorithms. Characteristics like less memory, high operational performance, small sized keys and rapid key generation process, and effective resource savings enable the modified ECC to obtain high efficiency. The encryption time of the proposed MECC system was 51ms with the key length 4096 bits, whereas existing method had 92ms as encryption time. Likewise With the key length of 4096 bits, the decryption time for the proposed model was 159ms. Accordingly the proposed system has reduced cipher text key size of 836KB when compared with the existing AES, Blow Fish, and Two Fish. Additionally, the key generation time (35 s) also seems to be considerably reduced when compared with the existing methods. These statements reveal that the proposed system outshine the state of art methods in terms of key generation time, encryption and decryption time and computational complexity.

The evolution of decentralized storage, propelled by blockchain advancements, has revolutionized data management. This paper focuses on content security in the InterPlanetary File System (IPFS), a leading decentralized storage network lacking inherent content encryption. To address this vulnerability, we propose a novel hybrid cryptographic algorithm, merging AES 128-bit encryption with Elliptic Curve Cryptography (ECC) key generation. The algorithm includes ECC key pairs, random IV generation, and content/AES key encryption using ECC public keys. Benchmarking against standard AES 256-bit methods shows a significant 20% acceleration in encryption speed and a 16% increase in decryption efficiency, affirming practicality for enhancing IPFS content security. This research contributes to securing decentralized storage and provides a performance-driven solution. The promising results highlight the viability of the proposed approach, advancing understanding and mitigating security concerns in IPFS and similar systems.

Secure and reliable surveillance over cognitive radio sensor networks in smart grid

Modern embedded electronic devices are gradually becoming an essential part of everyday lives, proving indispensable for daily activities. The growth of the Internet of things (IoT) technology fuels this phenomenon. IoT devices are found everywhere around us – smartphones, smartwatches, home automation, autonomous cars, and medical implants for human bodies. These devices find widespread use in medical imaging, video surveillance as embedded vision, cloud computing platforms, and military applications. Ensuring the reliability and safety of these devices is of prime importance, since these devices store sensitive data. A wide range of such embedded devices is a common target for intellectual property (IP) theft and reverse-engineering attacks by hackers to access confidential information and counterfeit integrated circuits. Physically unclonable functions (PUFs) are innovative hardware defense techniques that promise a fundamental change in our approach to many security problems. PUFs possess desirable properties like low cost, simple architectures, a light weight, versatility, and the valuable advantage of unclonability. This unclonable property is a consequence of intrinsic random variations at the micro- and nanoscale levels in the manufacturing processes and cannot be controlled or removed. This characteristic also serves as a unique fingerprint for the integrated circuit chips, similar to humans. The widespread usage of PUF techniques in security applications makes it imperative for hardware designers to appreciate its working and understand its uses in practice fully. This chapter aims to address these and other topics by presenting a detailed introduction of the concepts, evaluation parameters, and various ramifications of physically unclonable functions. PUF techniques also provide an economical alternative to ciphers and hash functions for secure cryptographic protocols. It is also necessary to provide security of IoT devices, have economic viability, and fit well with embedded devices’ heterogeneous nature. PUF circuits receive challenges as a sequence of bits and generate matching responses called a challenge-response pair, which can be thought of as a secret key or unique fingerprint. It also obviates the need for storing the keys in nonvolatile memories with dedicated protection, which is a costly affair. In this chapter, different PUFs, including optical PUF, delay-based PUFs, weak and strong PUFs, etc., the maturity of this technology, and their various applications are investigated. This chapter also emphasizes critical challenges toward PUF utilization in IoT and related fields and significant future development areas like critical public infrastructure, reconfigurability, and bit-specific reliability. The unique IoT domain protection criteria and how PUFs can be used to fulfill them are also examined. The chapter’s emphasis is on proven and well-understood strategies involving their benefits and shortcomings.

The use of physical unclonable functions (PUFs) to generate fingerprints for authentication of chips or larger electronic systems or for generation of internal cryptographic keys for data transfer is investigated. With the implementation of PUFs, each chip or electronic system has its own identity, which should prevent counterfeiting and &#x201C;night shift&#x201D; problems. There are various approaches to creating PUFs, and one of them is the so-called coating PUF, which would open the way to cost-effective and flexible protection during and after chip fabrication. In this work, we present two different capacitance measurement methods for fabricated PUF structures consisting of individual metal-oxide-semiconductor (MOS) capacitors. The goal is to obtain an easy and highly accurate measurement setup. Our fabricated PUF chips show an intended variation in capacitance and therefore generate characteristic fingerprints. We show that the parasitic capacitances and measurement variation are much smaller than the intended fluctuation of our PUF capacitances. This enables us to generate reliable and less error-prone fingerprints. Our presented measurement methods in combination with the technological PUF structures have shown to be accurate and reliable for flexible commercial application.

IoT devices rely on authentication mechanisms to render secure message exchange. During data transmission, scalability, data integrity, and processing time have been considered challenging aspects for a system constituted by IoT devices. The application of physical unclonable functions (PUFs) ensures secure data transmission among the internet of things (IoT) devices in a simplified network with an efficient time-stamped agreement. This paper proposes a secure, lightweight, cost-efficient reinforcement machine learning framework (SLCR-MLF) to achieve decentralization and security, thus enabling scalability, data integrity, and optimized processing time in IoT devices. PUF has been integrated into SLCR-MLF to improve the security of the cluster head node in the IoT platform during transmission by providing the authentication service for device-to-device communication. An IoT network gathers information of interest from multiple cluster members selected by the proposed framework. In addition, the software-defined secured (SDS) technique is integrated with SLCR-MLF to improve data integrity and optimize processing time in the IoT platform. Simulation analysis shows that the proposed framework outperforms conventional methods regarding the network’s lifetime, energy, secured data retrieval rate, and performance ratio. By enabling the proposed framework, number of residual nodes is reduced to 16%, energy consumption is reduced by up to 50%, almost 30% improvement in data retrieval rate, and network lifetime is improved by up to 1000 msec.

Physical Unclonable Function (PUF) is fast growing technology which utilizes the statistical variability of the manufacture variations acts as a finger print to the each device. It can be widely used in security applications such as device authentication, key generation and Intellectual Property (IP) protection. Due to the simplicity and low cost arbiter delay based PUFs have been mostly used as a cryptographic key in Internet of Things (IoT) devices. As conventional arbiter PUFs are suffers from less uniqueness and reliability. This paper provides designing of new buffer based arbiter PUF. It has been demonstrated that experimental results of new buffer based arbiter PUF shows the considerable improvement in the uniqueness and reliability of the proposed design and the Monte-Carlo analysis applied for delay variability of the PUFs.

Since physical unclonable functions (PUFs) are considered for various security applications such as authentication and key generation, the robustness of PUFs is vital. In prior works, various error correction codes, such as Bose-Chaudhuri-Hocquenghem (BCH) codes, were used to improve the robustness of PUFs. In this paper, we use polar codes, a new family of error correction codes, to improve the robustness of PUFs. Our results show that when compared with BCH codes, although polar codes have smaller minimum Hamming distances, they are more resistant to severe environmental effects.

The paper analyzes and proposes some enhancements of Ring Oscillator based Physical Unclonable Functions (PUFs) that are used to extract a unique signature of an integrated circuit in order to be used for device authentication purposes and/or key generation. We analyze in more details the concept developed by Suh et al. in 2007. Contrary to what authors claim, we show that the designer of the Ring Oscillator PUFs implemented in FPGAs needs precise control of placement and routing in order to get unique responses and repeatable results for each individual device, especially when the rest of the reconfigurable device should remain up gradable. One main disadvantage of the original design is its high power consumption. We propose a simple improvement that reduces the consumption of the PUF published by Suh et al. by up to 96.6\%. Last but not least, we point out that ring oscillators significantly influence one another and can even be locked. This questions the reliability of the PUF and should be taken into account during the design.