Robustness of Power Analysis Attack Resilient Adiabatic Logic: WCS-QuAL under PVT Variations

In this paper, we propose Without Charge Sharing Quasi Adiabatic Logic (WCS-QuAL) as a countermeasure against Power Analysis Attacks. We evaluate and compare our logic with the recently proposed secure adiabatic logic designs SPGAL and EE-SPFAL at frequencies ranging from 1MHz to 100MHz. Simulation results show that WCS-QuAL outperforms the existing secure adiabatic logic designs on the basis of % Normalized Energy Deviation (NED) and % Normalized Standard Deviation (NSD) at all simulated frequencies. Also, all 2-input gates using WCS-QuAL dissipate nearly equal energy for all possible input transitions. In addition, the energy dissipated by WCS-QuAL approaches to the energy dissipation of EESPFAL and SPGAL as the output load capacitance is increased above 100fF. To further evaluate and compare the performance, GF (24) bit-parallel multiplier was implemented as a design example. The impact of Process-Voltage-Temperature (PVT) variations, power supply scaling and technology on the performance of the three logic designs was investigated and compared. Simulation results show that WCS-QuAL passed the functionality test against PVT variations and can perform well against the power supply scaling (from 1.8V to 0.5V). It also exhibits the least value of %NED and %NSD against PVT variations and when the power supply is scaled down compared to EE-SPFAL and SPGAL. At lower technology, WCS-QuAL, shows more improvement in energy dissipation than EE-SPFAL

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

Investigating the effectiveness of Without Charge-Sharing Quasi-Adiabatic Logic for energy efficient and secure cryptographic implementations

Existing secure adiabatic logic designs use charge sharing inputs to deliver input independent energy dissipation and suffer from non-adiabatic losses (NAL) during the evaluation phase of the power-clock. However, using additional inputs present the overhead of generation, scheduling, and routing of the signals. Thus, we present “Without Charge-Sharing Quasi-Adiabatic Logic”, WCS-QuAL which doesn't require any charge sharing inputs and completely removes the NAL. The pre-layout and post-layout simulation results of the gates show that WCS-QuAL exhibits the lowest Normalized Energy Deviation (NED) and Normalized Standard Deviation (NSD) against all process corner variations at frequencies ranging from 1 MHz to 100 MHz. It also shows least variations in average energy dissipation at all five process corners. The simulation results show that the 8-bit Montgomery multiplier using WCS-QuAL exhibits the least value of NED and NSD at all the simulated frequencies and against power-supply scaling and dissipates the lowest energy at frequencies ranging from 20 MHz to 100 MHz

Symmetric Power Analysis Attack Resilient Adiabatic Logic for Smartcard Applications

On the whole existing secure adiabatic logic designs exhibit variations in current peaks and have asymmetric structures. However, asymmetric structure and variations in current peaks make the circuit vulnerable to Power Analysis Attacks (PAA). In this paper, we shall present a novel PAA resilient adiabatic logic which has a symmetric structure and exhibits the least variations in current peaks for basic gates as well as in 8-bit Montgomery multiplier. The proposed logic has been compared with two recently proposed secure adiabatic logic designs for operating frequencies ranging from 1MHz to 100MHz and power-supply scaling ranging from 0.6V to 1.8V. Simulation results of the gates show that our proposed logic exhibits the lowest Normalized Energy Deviation (NED) and Normalized Standard Deviation (NSD) under the said frequency variations. All the 2-input gates that deploy the proposed logic dissipate nearly the same average energy within 0.2% of each other at all the frequencies simulated and thus, along with the dataindependence,gate-function-independence is achieved. The paper will also report on the energy dissipated by the proposed logic which approaches that of the existing logic designs as the output load capacitance is increased above 100fF. The simulation results of the 8-bit adiabatic Montgomery multiplier show that the proposed logic exhibits the least value of NED and NSD under the said frequency variations and power-supply scaling. Finally, the paper will report on the current waveform graphs for variations in current peaks under power-clock scaling

A Novel Power Analysis Attack Resilient Adiabatic Logic without Charge Sharing

In this paper, we propose a novel power analysis attack resilient adiabatic logic which, unlike existing secure adiabatic logic designs doesn’t require any charge sharing between the output nodes of the gates. The proposed logic also removes the non-adiabatic losses (NAL) during the evaluation phase of the power-clock. We investigate and compare our proposed and the existing secure adiabatic logic across a range of “power-clock” frequencies on the basis of percentage Normalized Energy Deviation (%NED), percentage Normalized Standard Deviation(%NSD) and average energy dissipation. The pre-layout and post-layout simulation results show that our proposed logic exhibits the least value of %NED and %NSD in comparison to the existing secure adiabatic logic designs at the frequency ranging from 1MHz to 100MHz. Also, our proposed logic consumes the lowest energy

IDPAL – A Partially-Adiabatic Energy-Efficient Logic Family: Theory and Applications to Secure Computing

Low-power circuits and issues associated with them have gained a significant amount of attention in recent years due to the boom in portable electronic devices. Historically, low-power operation relied heavily on technology scaling and reduced operating voltage, however this trend has been slowing down recently due to the increased power density on chips. This dissertation introduces a new very-low power partially-adiabatic logic family called Input-Decoupled Partially-Adiabatic Logic (IDPAL) with applications in low-power circuits. Experimental results show that IDPAL reduces energy usage by 79% compared to equivalent CMOS implementations and by 25% when compared to the best adiabatic implementation. Experiments ranging from a simple buffer/inverter up to a 32-bit multiplier are explored and result in consistent energy savings, showing that IDPAL could be a viable candidate for a low-power circuit implementation. This work also shows an application of IDPAL to secure low-power circuits against power analysis attacks. It is often assumed that encryption algorithms are perfectly secure against attacks, however, most times attacks using side channels on the hardware implementation of an encryption operation are not investigated. Power analysis attacks are a subset of side channel attacks and can be implemented by measuring the power used by a circuit during an encryption operation in order to obtain secret information from the circuit under attack. Most of the previously proposed solutions for power analysis attacks use a large amount of power and are unsuitable for a low-power application. The almost-equal energy consumption for any given input in an IDPAL circuit suggests that this logic family is a good candidate for securing low-power circuits again power analysis attacks. Experimental results ranging from small circuits to large multipliers are performed and the power-analysis attack resistance of IDPAL is investigated. Results show that IDPAL circuits are not only low-power but also the most secure against power analysis attacks when compared to other adiabatic low-power circuits. Finally, a hybrid adiabatic-CMOS microprocessor design is presented. The proposed microprocessor uses IDPAL for the implementation of circuits with high switching activity (e.g. ALU) and CMOS logic for other circuits (e.g. memory, controller). An adiabatic-CMOS interface for transforming adiabatic signals to square-wave signals is presented and issues associated with a hybrid implementation and their solutions are also discussed

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

EVALUATION OF RESISTANCE TO SCA FOR DIFFERENT ARCHITECTURES OF ENCRYPTED CELL

This paper deals with a top down design of an example multiplexer cell that exhibits high immunity to Side Channel Attack (SCA). Four different solutions of the encrypted multiplexer cell are revised, and the best design adopted. The post-layout simulations prove resistance of the multiplexer logic cell to the SCA. Since the physical layout structure and the functionality of this kind of design is based on symmetry, concerns were expressed as to what will be the effectiveness of the method under real production conditions. To get a proper answer to that, the adequacy of the chosen design for the multiplexer cell, which uses the "No Short-circuit Current Dynamic Differential Logic" (NSDDL) method, is confirmed by observing a Normalized Standard Deviation (NSD)

Adiabatic Circuits for Power-Constrained Cryptographic Computations

This thesis tackles the need for ultra-low power operation in power-constrained cryptographic computations. An example of such an application could be smartcards. One of the techniques which has proven to have the potential of rendering ultra-low power operation is ‘Adiabatic Logic Technique’. However, the adiabatic circuits has associated challenges due to high energy dissipation of the Power-Clock Generator (PCG) and complexity of the multi-phase power-clocking scheme. Energy efficiency of the adiabatic system is often degraded due to the high energy dissipation of the PCG. In this thesis, nstep charging strategy using tank capacitors is considered for the power-clock generation and several design rules and trade-offs between the circuit complexity and energy efficiency of the PCG using n-step charging circuits have been proposed. Since pipelining is inherent in adiabatic logic design, careful selection of architecture is essential, as otherwise overhead in terms of area and energy due to synchronization buffers is induced specifically, in the case of adiabatic designs using 4-phase power-clocking scheme. Several architectures for the Montgomery multiplier using adiabatic logic technique are implemented and compared. An architecture which constitutes an appropriate trade-off between energy efficiency and throughput is proposed along with its methodology. Also, a strategy to reduce the overhead due to synchronization buffers is proposed. A modification in the Montgomery multiplication algorithm is proposed. Furthermore, a problem due to the application of power-clock gating in cascade stages of adiabatic logic is identified. The problem degrades the energy savings that would otherwise be obtained by the application of power-clock gating. A solution to this problem is proposed. Cryptographic implementations also present an obvious target for Power Analysis Attacks (PAA). There are several existing secure adiabatic logic designs which are proposed as a countermeasure against PAA. Shortcomings of the existing logic designs are identified, and two novel secure adiabatic logic designs are proposed as the countermeasures against PAA and improvement over the existing logic designs

Low-Power CMOS/FinFETs Circuit Using Adiabatic Switching Principle

Power consumption has become a very serious concern with regard to the rapid technology of Internet of Things (IoT) devices. The IoT devices, such as sensor nodes, secure cryptographic devices, and medical implantable devices are general embedded systems that require low power and operate at low-frequency speed. Countless efforts have been done to reduce power consumption in complementary metal oxide semiconductors (CMOS) through supply voltage downscaling, reducing unnecessary clock activity, avoiding long path circuit topology, etc. Another circuit technique for low-power purpose is by employing adiabatic switching principle. The adiabatic switching is commonly used in minimizing energy loss during charging/discharging period at all nodes of the circuit. In this paper, a low-power adiabatic CMOS/FinFETs circuit for low-power secure logic application is presented. The circuit speed, power consumption, and other evaluation metrics indicating the circuit performances will be compared among the proposed circuits and other circuit topologies that are available in the literature