This paper presents a design space exploration for SABER, one of the finalists in NISTs quantum-resistant public-key cryptographic standardization effort. Our design space exploration targets a 65nm ASIC platform and has resulted in the evaluation of
6 different architectures. Our exploration is initiated by setting a baseline architecture which is ported from FPGA. In order to improve the clock frequency (the primary goal in our exploration), we have employed several optimizations: (i) use of compiled memories in a smart synthesis fashion, (ii) pipelining, and (iii) logic sharing between SABER building blocks. The most optimized architecture utilizes four register files, achieves a remarkable clock frequency of 1GHz while only requiring an area of 0.314mm2. Moreover, physical synthesis is carried out for this architecture and a tapeout-ready layout is presented. The estimated dynamic power consumption of the high-frequency architecture is approximately 184mW for key generation and 187mW for encapsulation or decapsulation operations. These results strongly suggest that our optimized accelerator architecture is well suited for high-speed cryptographic applications.
This paper presents a high-level circuit obfuscation technique to prevent the theft of intellectual property (IP) of integrated circuits. In particular, our technique protects a class of circuits that relies on constant multiplications, such as filte
rs and neural networks, where the constants themselves are the IP to be protected. By making use of decoy constants and a key-based scheme, a reverse engineer adversary at an untrusted foundry is rendered incapable of discerning true constants from decoy constants. The time-multiplexed constant multiplication (TMCM) block of such circuits, which realizes the multiplication of an input variable by a constant at a time, is considered as our case study for obfuscation. Furthermore, two TMCM design architectures are taken into account; an implementation using a multiplier and a multiplierless shift-adds implementation. Optimization methods are also applied to reduce the hardware complexity of these architectures. The well-known satisfiability (SAT) and automatic test pattern generation (ATPG) attacks are used to determine the vulnerability of the obfuscated designs. It is observed that the proposed technique incurs small overheads in area, power, and delay that are comparable to the hardware complexity of prominent logic locking methods. Yet, the advantage of our approach is in the insight that constants -- instead of arbitrary circuit nodes -- become key-protected.
The interplay between security and reliability is poorly understood. This paper shows how triple modular redundancy affects a side-channel attack (SCA). Our counterintuitive findings show that modular redundancy can increase SCA resiliency.
Optical tweezers find applications in various fields, ranging from biology to physics. One of the fundamental steps necessary to perform quantitative measurements using trapped particles is the calibration of the tweezers spring constant. This can be
done through power spectral density analysis, from forward scattering detection of the particles position. In this work, we propose and experimentally test simplifications to such measurement procedure, aimed at reducing post-processing of recorded data and dealing with acquisition devices that have frequency-dependent electronic noise. In the same line of simplifying the tweezer setup, we also present a knife-edge detection scheme that can substitute standard position-sensitive detectors.
It is generally well known that the Standard Model of particle physics is not the ultimate theory of fundamental interactions as it has inumerous unsolved problems, so it must be extended. Deciphering the nature of dark matter remains one of the grea
t challenges of contemporary physics. Supersymmetry is probably the most attractive extension of the SM. In the first part of this thesis we study the interparticle potentials generated by the interactions between spin-1/2 sources that are mediated by spin-1 particles in the limit of low momentum transfer. We investigate different representations of spin-1 particle to see how it modifies the profiles of the interparticle potentials and we also include in our analysis all types of couplings between fermionic currents and the mediator boson. The spin- and velocity-dependent interparticle potentials that we obtain can be used to explain effects possibly associated to new macroscopic forces such as modifications of the inverse-square law and possible spin-gravity coupling effects. The second part of this thesis is based on the dark matter phenomenology of well-motivated $U(1)$ extensions of the Minimal Supersymmetric Standard Model. In these models the right-handed sneutrino is a good DM candidate whose dark matter properties are in agreement with the present relic density and current experimental limits on the DM-nucleon scattering cross section. In order to see how heavy can the RH sneutrino be as a viable thermal dark matter candidate we explore its DM properties in the parameter region that minimize its relic density via resonance effects and thus allows it to be a heavier DM particle. We found that the RH sneutrino can behave as a good DM particle within minimal cosmology even with masses of the order of tens of TeV, which is much above the masses that viable thermal DM candidates usually have in most of dark matter particle models.
This work lists and describes the main recent strategies for building fixed-length, dense and distributed representations for words, based on the distributional hypothesis. These representations are now commonly called word embeddings and, in additio
n to encoding surprisingly good syntactic and semantic information, have been proven useful as extra features in many downstream NLP tasks.
We present a method to build a probability density function (pdf) for the age of a star based on its peculiar velocities $U$, $V$ and $W$ and its orbital eccentricity. The sample used in this work comes from the Geneva-Copenhagen Survey (GCS) which c
ontains both the spatial velocities, orbital eccentricities and isochronal ages for about $14,000$ stars. Using the GCS stars, we fitted the parameters that describe the relations between the distributions of kinematical properties and age. This parametrization allows us to obtain an age probability from the kinematical data. From this age pdf, we estimate an individual average age for the star using the most likely age and the expected age. We have obtained the stellar age pdf for the age of $9,102$ stars from the GCS and have shown that the distribution of individual ages derived from our method is in good agreement with the distribution of isochronal ages. We also observe a decline in the mean metallicity with our ages for stars younger than 7 Gyr, similar to the one observed for isochronal ages. This method can be useful for the estimation of rough stellar ages for those stars that fall in areas of the HR diagram where isochrones are tightly crowded. As an example of this method, we estimate the age of Trappist-1, which is a M8V star, obtaining the age of $t(UVW) = 12.50(+0.29-6.23)$ Gyr.
