This paper presents a method for designing a class of countermeasures for DPA attacks based on attenuation of current variations. In this class of countermeasures, designers aim at decreasing the dynamic current varia...This paper presents a method for designing a class of countermeasures for DPA attacks based on attenuation of current variations. In this class of countermeasures, designers aim at decreasing the dynamic current variations to reduce the information that can be extracted from the current consumption of secure microsystems. The proposed method is based on a novel formula that calculates the number of current traces required for a successful DPA attack using the characteristics of the microsystem current signal and the external noise of the measurement setup. The different stages of the proposed method are illustrated through designing an example current flattening circuit. Meanwhile validity and applicability of the proposed formula is verified by comparing theoretical results with those obtained experimentally for the example circuit. The proposed formula not only estimates the required level of attenuation for a target level of robustness defined by design requirements, it also predicts the effectiveness of a countermeasure using simulation results therefore dramatically reducing the time to design of secure microsystems.展开更多
In the originally published version of this article1,references 83-92 were inadvertently included in the reference list due to a glitch in the LaTeX template used.These references have been removed from the corrected ...In the originally published version of this article1,references 83-92 were inadvertently included in the reference list due to a glitch in the LaTeX template used.These references have been removed from the corrected version of the article.展开更多
The index of refraction plays a decisive role in the design and classification of optical materials and devices;therefore,its proper and accurate determination is essential.In most refractive index(RI)sensing schemes,...The index of refraction plays a decisive role in the design and classification of optical materials and devices;therefore,its proper and accurate determination is essential.In most refractive index(RI)sensing schemes,however,there is a trade-off between providing high-resolution measurements and covering a wide range of RIs.We propose and experimentally demonstrate a novel mechanism for sensing the index of refraction of a medium by utilizing the orbital angular momentum(OAM)of structured light.Using a superposition of co-propagating monochromatic higher-order Bessel beams with equally spaced longitudinal wavenumbers,in a comb-like setting,we generate non-diffracting rotating light structures in which the orientation of the beam’s intensity profile is sensitive to the RI of the medium(here,a fluid).In principle,the sensitivity of this scheme can exceed~2700°/RI unit(RIU)with a resolution of~105 RIU.Furthermore,we show how the unbounded degrees of freedom associated with OAM can be deployed to offer a wide dynamic range by generating structured light that evolves into different patterns based on the change in RI.The rotating light structures are generated by a programmable spatial light modulator.This provides dynamic control over the sensitivity,which can be tuned to perform coarse or fine measurements of the RI in real time.This,in turn,allows high sensitivity and resolution to be achieved simultaneously over a very wide dynamic range,which is a typical tradeoff in all RI sensing schemes.We thus envision that this method will open new directions in refractometry and remote sensing.展开更多
Focusing incident power into an area of high concentration is of significant interest for various applications.In optics,this has been traditionally achieved with lenses where a higher curvature and lens permittivity ...Focusing incident power into an area of high concentration is of significant interest for various applications.In optics,this has been traditionally achieved with lenses where a higher curvature and lens permittivity typically result in shorter focal distances(low f/D).In this work,we present designs and techniques for collecting,refracting and guiding incident light into an area of high power concentration(a hot spot)at extremely short distances.Specifically,a flat low-profile focusing mechanism is presented using a hetero-junction of anisotropic metamaterials(MTMs).The hetero-junction is formed from two cleaved finite slabs of low(near zero)permittivity anisotropic MTMs with rotated optical axes.The MTMs have near zero longitudinal permittivity while matched in the transverse direction.Such MTMs are shown to provide a unique ability to bend the transverse magnetic or p-polarized light away from the normal and along the interface,contrary to conventional dielectrics,and with minimal reflections;hence allowing for a low profile design.Realizations in the optical regime are presented using periodic bilayers of metal and dielectric.The proposed hetero-junction focusing device concentrates the normally incident plane wave and/or beam into a corresponding focal region similar to a lens via multiple refractions.The hetero-junction is capable of creating a hot spot very close to the device,much closer than dielectric lenses and it significantly outperforms the size requirements of thick high curvature lenses with low f/D ratios.The proposed designs can find applications in various scenarios including solar and thermo photovoltaics,photodetectors,concentrated photovoltaics,non-imaging optics,micro-and nano-Fresnel lenses.展开更多
By taking advantage of the absence of diffraction limit restrictions in plasmonic structures,strong modal confinement is made possible,paving the way for improved optical processes and miniaturized photonic circuit in...By taking advantage of the absence of diffraction limit restrictions in plasmonic structures,strong modal confinement is made possible,paving the way for improved optical processes and miniaturized photonic circuit integration.Indium tin oxide(ITO)has emerged as a promising plasmonic material that serves as a relatively low-carrier density Drude metal by its electro-optic tunability and versatility as an integrative oxide.We herein demonstrate the facile integration of SiO_(2)/ITO heterointerfaces into metal-insulator-semiconductor(MIS)electro-optic structures.The first MIS device employs a SiO_(2)/ITO heterostructure grown on thin polycrystalline titanium nitride(poly-TiN)and capped at the ITO side with thin aluminum(Al)film contact electrode.The TiN interlayer acts as a bottom electrode,forming a metal-insulator-semiconductor-metal(MISM)heterojunction device,and grows directly on(100)-oriented silicon(Si).This MISM device enables one to examine the electrical properties of semiconductive ITO layers.The second MIS device incorporates a semiconductive ITO layer with a SiO_(2)dielectric spacer implemented on a silicon-on-insulator(SOI)platform,forming a graded-index coupled hybrid plasmonic waveguide(CHPW)modulator.This device architecture represents a crucial step towards realizing plasmonic modulation using oxide materials.The CHPW device performance presented herein provides a proof-of-concept that demonstrates the advantages offered by such device topology to perform optical modulation via charge carrier dispersion.The graded-index CHPW can be dynamically reconfigured for amplitude,phase,or 4-quadrature amplitude modulation utilizing a triode-like biasing strategy.It exhibited extinction ratio(ER)and insertion loss(IL)levels of around 1 dB/μm and 0.128 dB/μm,respectively,for a 10μm waveguide length.展开更多
Large intelligent surface/antennas(LISA),a two-dimensional artificial structure with a large number of reflective-surface/antenna elements,is a promising reflective radio technology to construct programmable wireless ...Large intelligent surface/antennas(LISA),a two-dimensional artificial structure with a large number of reflective-surface/antenna elements,is a promising reflective radio technology to construct programmable wireless environments in a smart way.Specifically,each element of the LISA adjusts the reflection of the incident electromagnetic waves with unnatural properties,such as negative refraction,perfect absorption,and anomalous reflection,thus the wireless environments can be software-defined according to various design objectives.In this paper,we introduce the reflective radio basics,including backscattering principles,backscatter communication,reflective relay,the fundamentals and implementations of LISA technology.Then,we present an overview of the state-of-the-art research on emerging applications of LISA-aided wireless networks.Finally,the limitations,challenges,and open issues associated with LISA for future wireless applications are discussed.展开更多
文摘This paper presents a method for designing a class of countermeasures for DPA attacks based on attenuation of current variations. In this class of countermeasures, designers aim at decreasing the dynamic current variations to reduce the information that can be extracted from the current consumption of secure microsystems. The proposed method is based on a novel formula that calculates the number of current traces required for a successful DPA attack using the characteristics of the microsystem current signal and the external noise of the measurement setup. The different stages of the proposed method are illustrated through designing an example current flattening circuit. Meanwhile validity and applicability of the proposed formula is verified by comparing theoretical results with those obtained experimentally for the example circuit. The proposed formula not only estimates the required level of attenuation for a target level of robustness defined by design requirements, it also predicts the effectiveness of a countermeasure using simulation results therefore dramatically reducing the time to design of secure microsystems.
文摘In the originally published version of this article1,references 83-92 were inadvertently included in the reference list due to a glitch in the LaTeX template used.These references have been removed from the corrected version of the article.
基金the support from the Natural Sciences and Engineering Research Council in Canada,the Ontario Graduate Scholarship,FAPESP(Grant No.2015/26444-8)CNPq(Grant No.304718/2016-5).
文摘The index of refraction plays a decisive role in the design and classification of optical materials and devices;therefore,its proper and accurate determination is essential.In most refractive index(RI)sensing schemes,however,there is a trade-off between providing high-resolution measurements and covering a wide range of RIs.We propose and experimentally demonstrate a novel mechanism for sensing the index of refraction of a medium by utilizing the orbital angular momentum(OAM)of structured light.Using a superposition of co-propagating monochromatic higher-order Bessel beams with equally spaced longitudinal wavenumbers,in a comb-like setting,we generate non-diffracting rotating light structures in which the orientation of the beam’s intensity profile is sensitive to the RI of the medium(here,a fluid).In principle,the sensitivity of this scheme can exceed~2700°/RI unit(RIU)with a resolution of~105 RIU.Furthermore,we show how the unbounded degrees of freedom associated with OAM can be deployed to offer a wide dynamic range by generating structured light that evolves into different patterns based on the change in RI.The rotating light structures are generated by a programmable spatial light modulator.This provides dynamic control over the sensitivity,which can be tuned to perform coarse or fine measurements of the RI in real time.This,in turn,allows high sensitivity and resolution to be achieved simultaneously over a very wide dynamic range,which is a typical tradeoff in all RI sensing schemes.We thus envision that this method will open new directions in refractometry and remote sensing.
基金This work was supported by the Natural Sciences and Engineering Research Council of Canada and by Defence Research and Development Canada.
文摘Focusing incident power into an area of high concentration is of significant interest for various applications.In optics,this has been traditionally achieved with lenses where a higher curvature and lens permittivity typically result in shorter focal distances(low f/D).In this work,we present designs and techniques for collecting,refracting and guiding incident light into an area of high power concentration(a hot spot)at extremely short distances.Specifically,a flat low-profile focusing mechanism is presented using a hetero-junction of anisotropic metamaterials(MTMs).The hetero-junction is formed from two cleaved finite slabs of low(near zero)permittivity anisotropic MTMs with rotated optical axes.The MTMs have near zero longitudinal permittivity while matched in the transverse direction.Such MTMs are shown to provide a unique ability to bend the transverse magnetic or p-polarized light away from the normal and along the interface,contrary to conventional dielectrics,and with minimal reflections;hence allowing for a low profile design.Realizations in the optical regime are presented using periodic bilayers of metal and dielectric.The proposed hetero-junction focusing device concentrates the normally incident plane wave and/or beam into a corresponding focal region similar to a lens via multiple refractions.The hetero-junction is capable of creating a hot spot very close to the device,much closer than dielectric lenses and it significantly outperforms the size requirements of thick high curvature lenses with low f/D ratios.The proposed designs can find applications in various scenarios including solar and thermo photovoltaics,photodetectors,concentrated photovoltaics,non-imaging optics,micro-and nano-Fresnel lenses.
基金supported by the Natural Sciences and Engineering Research Council of Canada.
文摘By taking advantage of the absence of diffraction limit restrictions in plasmonic structures,strong modal confinement is made possible,paving the way for improved optical processes and miniaturized photonic circuit integration.Indium tin oxide(ITO)has emerged as a promising plasmonic material that serves as a relatively low-carrier density Drude metal by its electro-optic tunability and versatility as an integrative oxide.We herein demonstrate the facile integration of SiO_(2)/ITO heterointerfaces into metal-insulator-semiconductor(MIS)electro-optic structures.The first MIS device employs a SiO_(2)/ITO heterostructure grown on thin polycrystalline titanium nitride(poly-TiN)and capped at the ITO side with thin aluminum(Al)film contact electrode.The TiN interlayer acts as a bottom electrode,forming a metal-insulator-semiconductor-metal(MISM)heterojunction device,and grows directly on(100)-oriented silicon(Si).This MISM device enables one to examine the electrical properties of semiconductive ITO layers.The second MIS device incorporates a semiconductive ITO layer with a SiO_(2)dielectric spacer implemented on a silicon-on-insulator(SOI)platform,forming a graded-index coupled hybrid plasmonic waveguide(CHPW)modulator.This device architecture represents a crucial step towards realizing plasmonic modulation using oxide materials.The CHPW device performance presented herein provides a proof-of-concept that demonstrates the advantages offered by such device topology to perform optical modulation via charge carrier dispersion.The graded-index CHPW can be dynamically reconfigured for amplitude,phase,or 4-quadrature amplitude modulation utilizing a triode-like biasing strategy.It exhibited extinction ratio(ER)and insertion loss(IL)levels of around 1 dB/μm and 0.128 dB/μm,respectively,for a 10μm waveguide length.
基金This work was supported by the National Natural Science Foundation of China under Grants U1801261,61631005,and 61571100.
文摘Large intelligent surface/antennas(LISA),a two-dimensional artificial structure with a large number of reflective-surface/antenna elements,is a promising reflective radio technology to construct programmable wireless environments in a smart way.Specifically,each element of the LISA adjusts the reflection of the incident electromagnetic waves with unnatural properties,such as negative refraction,perfect absorption,and anomalous reflection,thus the wireless environments can be software-defined according to various design objectives.In this paper,we introduce the reflective radio basics,including backscattering principles,backscatter communication,reflective relay,the fundamentals and implementations of LISA technology.Then,we present an overview of the state-of-the-art research on emerging applications of LISA-aided wireless networks.Finally,the limitations,challenges,and open issues associated with LISA for future wireless applications are discussed.
