NOVEL RESOURCE EFFICIENT CIRCUIT DESIGNS FOR REBOOTING COMPUTING

CMOS based computing is reaching its limits. To take computation beyond Moores law (the number of transistors and hence processing power on a chip doubles every 18 months to 3 years) requires research explorations in (i) new materials, devices, and processes, (ii) new architectures and algorithms, (iii) new paradigm of logic bit representation. The focus is on fundamental new ways to compute under the umbrella of rebooting computing such as spintronics, quantum computing, adiabatic and reversible computing. Therefore, this thesis highlights explicitly Quantum computing and Adiabatic logic, two new computing paradigms that come under the umbrella of rebooting computing. Quantum computing is investigated for its promising application in high-performance computing. The first contribution of this thesis is the design of two resource-efficient designs for quantum integer division. The first design is based on non-restoring division algorithm and the second one is based on restoring division algorithm. Both the designs are compared and shown to be superior to the existing work in terms of T-count and T-depth. The proliferation of IoT devices which work on low-power also has drawn interests to the rebooting computing. Hence, the second contribution of this thesis is proving that Adiabatic Logic is a promising candidate for implementation in IoT devices. The adiabatic logic family called Symmetric Pass Gate Adiabatic Logic (SPGAL) is implemented in PRESENT-80 lightweight algorithm. Adiabatic Logic is extended to emerging transistor devices

ENERGY-EFFICIENT AND SECURE HARDWARE FOR INTERNET OF THINGS (IoT) DEVICES

Internet of Things (IoT) is a network of devices that are connected through the Internet to exchange the data for intelligent applications. Though IoT devices provide several advantages to improve the quality of life, they also present challenges related to security. The security issues related to IoT devices include leakage of information through Differential Power Analysis (DPA) based side channel attacks, authentication, piracy, etc. DPA is a type of side-channel attack where the attacker monitors the power consumption of the device to guess the secret key stored in it. There are several countermeasures to overcome DPA attacks. However, most of the existing countermeasures consume high power which makes them not suitable to implement in power constraint devices. IoT devices are battery operated, hence it is important to investigate the methods to design energy-efficient and secure IoT devices not susceptible to DPA attacks. In this research, we have explored the usefulness of a novel computing platform called adiabatic logic, low-leakage FinFET devices and Magnetic Tunnel Junction (MTJ) Logic-in-Memory (LiM) architecture to design energy-efficient and DPA secure hardware. Further, we have also explored the usefulness of adiabatic logic in the design of energy-efficient and reliable Physically Unclonable Function (PUF) circuits to overcome the authentication and piracy issues in IoT devices. Adiabatic logic is a low-power circuit design technique to design energy-efficient hardware. Adiabatic logic has reduced dynamic switching energy loss due to the recycling of charge to the power clock. As the first contribution of this dissertation, we have proposed a novel DPA-resistant adiabatic logic family called Energy-Efficient Secure Positive Feedback Adiabatic Logic (EE-SPFAL). EE-SPFAL based circuits are energy-efficient compared to the conventional CMOS based design because of recycling the charge after every clock cycle. Further, EE-SPFAL based circuits consume uniform power irrespective of input data transition which makes them resilience against DPA attacks. Scaling of CMOS transistors have served the industry for more than 50 years in providing integrated circuits that are denser, and cheaper along with its high performance, and low power. However, scaling of the transistors leads to increase in leakage current. Increase in leakage current reduces the energy-efficiency of the computing circuits,and increases their vulnerability to DPA attack. Hence, it is important to investigate the crypto circuits in low leakage devices such as FinFET to make them energy-efficient and DPA resistant. In this dissertation, we have proposed a novel FinFET based Secure Adiabatic Logic (FinSAL) family. FinSAL based designs utilize the low-leakage FinFET device along with adiabatic logic principles to improve energy-efficiency along with its resistance against DPA attack. Recently, Magnetic Tunnel Junction (MTJ)/CMOS based Logic-in-Memory (LiM) circuits have been explored to design low-power non-volatile hardware. Some of the advantages of MTJ device include non-volatility, near-zero leakage power, high integration density and easy compatibility with CMOS devices. However, the differences in power consumption between the switching of MTJ devices increase the vulnerability of Differential Power Analysis (DPA) based side-channel attack. Further, the MTJ/CMOS hybrid logic circuits which require frequent switching of MTJs are not very energy-efficient due to the significant energy required to switch the MTJ devices. In the third contribution of this dissertation, we have investigated a novel approach of building cryptographic hardware in MTJ/CMOS circuits using Look-Up Table (LUT) based method where the data stored in MTJs are constant during the entire encryption/decryption operation. Currently, high supply voltage is required in both writing and sensing operations of hybrid MTJ/CMOS based LiM circuits which consumes a considerable amount of energy. In order to meet the power budget in low-power devices, it is important to investigate the novel design techniques to design ultra-low-power MTJ/CMOS circuits. In the fourth contribution of this dissertation, we have proposed a novel energy-efficient Secure MTJ/CMOS Logic (SMCL) family. The proposed SMCL logic family consumes uniform power irrespective of data transition in MTJ and more energy-efficient compared to the state-of-art MTJ/ CMOS designs by using charge sharing technique. The other important contribution of this dissertation is the design of reliable Physical Unclonable Function (PUF). Physically Unclonable Function (PUF) are circuits which are used to generate secret keys to avoid the piracy and device authentication problems. However, existing PUFs consume high power and they suffer from the problem of generating unreliable bits. This dissertation have addressed this issue in PUFs by designing a novel adiabatic logic based PUF. The time ramp voltages in adiabatic PUF is utilized to improve the reliability of the PUF along with its energy-efficiency. Reliability of the adiabatic logic based PUF proposed in this dissertation is tested through simulation based temperature variations and supply voltage variations

Designing Novel Hardware Security Primitives for Smart Computing Devices

Smart computing devices are miniaturized electronics devices that can sense their surroundings, communicate, and share information autonomously with other devices to work cohesively. Smart devices have played a major role in improving quality of the life and boosting the global economy. They are ubiquitously present, smart home, smart city, smart girds, industry, healthcare, controlling the hazardous environment, and military, etc. However, we have witnessed an exponential rise in potential threat vectors and physical attacks in recent years. The conventional software-based security approaches are not suitable in the smart computing device, therefore, hardware-enabled security solutions have emerged as an attractive choice. Developing hardware security primitives, such as True Random Number Generator (TRNG) and Physically Unclonable Function (PUF) from electrical properties of the sensor could be a novel research direction. Secondly, the Lightweight Cryptographic (LWC) ciphers used in smart computing devices are found vulnerable against Correlation Power Analysis (CPA) attack. The CPA performs statistical analysis of the power consumption of the cryptographic core and reveals the encryption key. The countermeasure against CPA results in an increase in energy consumption, therefore, they are not suitable for battery operated smart computing devices. The primary goal of this dissertation is to develop novel hardware security primitives from existing sensors and energy-efficient LWC circuit implementation with CPA resilience. To achieve these. we focus on developing TRNG and PUF from existing photoresistor and photovoltaic solar cell sensors in smart devices Further, we explored energy recovery computing (also known as adiabatic computing) circuit design technique that reduces the energy consumption compared to baseline CMOS logic design and same time increasing CPA resilience in low-frequency applications, e.g. wearable fitness gadgets, hearing aid and biomedical instruments. The first contribution of this dissertation is to develop a TRNG prototype from the uncertainty present in photoresistor sensors. The existing sensor-based TRNGs suffer a low random bit generation rate, therefore, are not suitable in real-time applications. The proposed prototype has an average random bit generation rate of 8 kbps, 32 times higher than the existing sensor-based TRNG. The proposed lightweight scrambling method results in random bit entropy close to ideal value 1. The proposed TRNG prototype passes all 15 statistical tests of the National Institute of Standards and Technology (NIST) Statistical Test Suite with quality performance. The second contribution of this dissertation is to develop an integrated TRNG-PUF designed using photovoltaic solar cell sensors. The TRNG and PUF are mutually independent in the way they are designed, therefore, integrating them as one architecture can be beneficial in resource-constrained computing devices. We propose a novel histogram-based technique to segregate photovoltaic solar cell sensor response suitable for TRNG and PUF respectively. The proposed prototype archives approximately 34\% improvement in TRNG output. The proposed prototype achieves an average of 92.13\% reliability and 50.91\% uniformity performance in PUF response. The proposed sensor-based hardware security primitives do not require additional interfacing hardware. Therefore, they can be ported as a software update on existing photoresistor and photovoltaic sensor-based devices. Furthermore, the sensor-based design approach can identify physically tempered and faulty sensor nodes during authentication as their response bit differs. The third contribution is towards the development of a novel 2-phase sinusoidal clocking implementation, 2-SPGAL for existing Symmetric Pass Gate Adiabatic Logic (SPGAL). The proposed 2-SPGAL logic-based LWC cipher PRESENT shows an average of 49.34\% energy saving compared to baseline CMOS logic implementation. Furthermore, the 2-SPGAL prototype has an average of 22.76\% better energy saving compared to 2-EE-SPFAL (2-phase Energy-Efficient-Secure Positive Feedback Adiabatic Logic). The proposed 2-SPGAL was tested for energy-efficiency performance for the frequency range of 50 kHz to 250 kHz, used in healthcare gadgets and biomedical instruments. The proposed 2-SPGAL based design saves 16.78\% transistor count compared to 2-EE-SPFAL counterpart. The final contribution is to explore Clocked CMOS Adiabatic Logic (CCAL) to design a cryptographic circuit. Previously proposed 2-SPGAL and 2-EE-SPFAL uses two complementary pairs of the transistor evaluation network, thus resulting in a higher transistor count compared to the CMOS counterpart. The CCAL structure is very similar to CMOS and unlike 2-SPGAL and 2-EE-SPFAL, it does not require discharge circuitry to improve security performance. The case-study implementation LWC cipher PRESENT S-Box using CCAL results into 45.74\% and 34.88\% transistor count saving compared to 2-EE-SPFAL and 2-SPGAL counterpart. Furthermore, the case-study implementation using CCAL shows more than 95\% energy saving compared to CMOS logic at frequency range 50 kHz to 125 kHz, and approximately 60\% energy saving at frequency 250 kHz. The case study also shows 32.67\% and 11.21\% more energy saving compared to 2-EE-SPFAL and 2-SPGAL respectively at frequency 250 kHz. We also show that 200 fF of tank capacitor in the clock generator circuit results in optimum energy and security performance in CCAL

Single-Rail Adiabatic Logic for Energy-Efficient and CPA-Resistant Cryptographic Circuit in Low-Frequency Medical Devices

Designing energy-efficient and secure cryptographic circuits in low-frequency medical devices are challenging due to low-energy requirements. Also, the conventional CMOS logic-based cryptographic circuits solutions in medical devices can be vulnerable to side-channel attacks (e.g. correlation power analysis (CPA)). In this article, we explored single-rail Clocked CMOS Adiabatic Logic (CCAL) to design an energy-efficient and secure cryptographic circuit for low-frequency medical devices. The performance of the CCAL logic-based circuits was checked with a power clock generator (2N2P-PCG) integrated into the design for the frequency range of 50 kHz to 250 kHz. The CCAL logic gates show an average of approximately 48% energy-saving and more than 95% improvement in security metrics performance compared to its CMOS logic gate counterparts. Further, the CCAL based circuits are also compared for energy-saving performance against dual-rail adiabatic logic, 2-EE-SPFAL, and 2-SPGAL. The adiabatic CCAL gates save on an average of 55% energy saving compared to 2-EE-SPFAL and 2-SPGAL over the frequency range of 50 kHz to 250 kHz. To check the efficacy of CCAL to design a larger cryptographic circuit, we implemented a case-study design of a Substitution-box (S-box) of popular lightweight PRESENT-80 encryption. The case-study implementation (2N2P-PCG integrated into the design) using CCAL shows more than 95% energy saving compared to CMOS for the frequency 50 kHz to 125 kHz and around 60% energy saving at frequency 250 kHz. At 250 kHz, compared to the dual-rail adiabatic designs of S-box based on 2-EE-SPFAL and 2-SPGAL, the CCAL based S-box shows 32.67% and 11.21% of energy savings, respectively. Additionally, the CCAL logic gate structure requires a lesser number of transistors compared to dual-rail adiabatic logic. The case-study implementation using CCAL saves 45.74% and 34.88% transistor counts compared to 2-EE-SPFAL and 2-SPGAL. The article also presents the effect of varying tank capacitance in 2N2P-PCG over energy efficiency and security performance. The CCAL based case-study was also subjected against CPA. The CCAL-based S-box case study successfully protects the revelation of the encryption key against the CPA attack, However, the key was revealed in CMOS-based case-study implementation

Privacy-Aware Architectures for NFC and RFID Sensors in Healthcare Applications

World population and life expectancy have increased steadily in recent years, raising issues regarding access to medical treatments and related expenses. Through last-generation medical sensors, NFC (Near Field Communication) and radio frequency identification (RFID) technologies can enable healthcare internet of things (H-IoT) systems to improve the quality of care while reducing costs. Moreover, the adoption of point-of-care (PoC) testing, performed whenever care is needed to return prompt feedback to the patient, can generate great synergy with NFC/RFID H-IoT systems. However, medical data are extremely sensitive and require careful management and storage to protect patients from malicious actors, so secure system architectures must be conceived for real scenarios. Existing studies do not analyze the security of raw data from the radiofrequency link to cloud-based sharing. Therefore, two novel cloud-based system architectures for data collected from NFC/RFID medical sensors are proposed in this paper. Privacy during data collection is ensured using a set of classical countermeasures selected based on the scientific literature. Then, data can be shared with the medical team using one of two architectures: in the first one, the medical system manages all data accesses, whereas in the second one, the patient defines the access policies. Comprehensive analysis of the H-IoT system can be useful for fostering research on the security of wearable wireless sensors. Moreover, the proposed architectures can be implemented for deploying and testing NFC/RFID-based healthcare applications, such as, for instance, domestic PoCs

Sustainable and Short-range Communication Techniques for Smart Industry Environment

The industries of the future, call for unprecedented flexibility whereas, the communication technology intervention is the best solution. For sustainable development goals in industry automation demand Dedicated Short-range Communication (DSRC) with Intelligent Transportation Systems (ITS). One of these systems' view point is the regular dissemination of safety messages. Integrating this technology with the existing Industry automation is a technical challenge. Integration also involves in imparting intelligence through digitalization of communication. With a cost of overhead power, Error Controlling Codes (ECC) provides a reliable and error-free DSRC communication system. In this paper, low power and secure digital VLSI architecture is presented to meet the sustainable integrated communication technology on chip circuitry for industry 4.0. The circuit's performance is measured in Cadence utilizing 18 nm FinFET-based ECRL adiabatic logic. The design provides maximum power savings of 99.49% over reported values for CMOS and 99.41% for pass transistor implementation. The adiabatic logic circuits constructed with ECRL are shown to have consistent peak current traces and hence can survive differential power analysis (DPA) attacks, resulting in improved circuit security