A Conditionally Chaotic Physically Unclonable Function Design Framework with High Reliability

Physically Unclonable Function (PUF) circuits are promising low-overhead hardware security primitives, but are often gravely susceptible to machine learning–based modeling attacks. Recently, chaotic PUF circuits have been proposed that show greater robustness to modeling attacks. However, they often suffer from unacceptable overhead, and their analog components are susceptible to low reliability. In this article, we propose the concept of a conditionally chaotic PUF that enhances the reliability of the analog components of a chaotic PUF circuit to a level at par with their digital counterparts. A conditionally chaotic PUF has two modes of operation: bistable and chaotic , and switching between these two modes is conveniently achieved by setting a mode-control bit (at a secret position) in an applied input challenge. We exemplify our PUF design framework for two different PUF variants—the CMOS Arbiter PUF and a previously proposed hybrid CMOS-memristor PUF, combined with a hardware realization of the Lorenz system as the chaotic component. Through detailed circuit simulation and modeling attack experiments, we demonstrate that the proposed PUF circuits are highly robust to modeling and cryptanalytic attacks, without degrading the reliability of the original PUF that was combined with the chaotic circuit, and incurs acceptable hardware footprint.

Sign Detection and Signed Integer Comparison for the 3-Moduli Set {2^n±1,2^(n+k)}

Comparison, division and sign detection are considered complicated operations in residue number system (RNS). A straightforward solution is to convert RNS numbers into binary formats and then perform complicated operations using conventional binary operators. If efficient circuits are provided for comparison, division and sign detection, the application of RNS can be extended to the cases including these operations.For RNS comparison in the 3-moduli set , we have only found one hardware realization. In this paper, an efficient RNS comparator is proposed for the moduli set which employs sign detection method and operates more efficient than its counterparts. The proposed sign detector and comparator utilize dynamic range partitioning (DRP), which has been recently presented for unsigned RNS comparison. Delay and cost of the proposed comparator are lower than the previous works and makes it appropriate for RNS applications with limited delay and cost.

Software-driven Security Attacks: From Vulnerability Sources to Durable Hardware Defenses

There is an increasing body of work in the area of hardware defenses for software-driven security attacks. A significant challenge in developing these defenses is that the space of security vulnerabilities and exploits is large and not fully understood. This results in specific point defenses that aim to patch particular vulnerabilities. While these defenses are valuable, they are often blindsided by fresh attacks that exploit new vulnerabilities. This article aims to address this issue by suggesting ways to make future defenses more durable based on an organization of security vulnerabilities as they arise throughout the program life cycle. We classify these vulnerability sources through programming, compilation, and hardware realization, and we show how each source introduces unintended states and transitions into the implementation. Further, we show how security exploits gain control by moving the implementation to an unintended state using knowledge of these sources and how defenses work to prevent these transitions. This framework of analyzing vulnerability sources, exploits, and defenses provides insights into developing durable defenses that could defend against broader categories of exploits. We present illustrative case studies of four important attack genealogies—showing how they fit into the presented framework and how the sophistication of the exploits and defenses have evolved over time, providing us insights for the future.

PROCEDURE FOR EVALUATION OF THE SUPPORTING FREQUENCY SIGNAL OF THE SATELLITE COMMUNICATION SYSTEM IN CONTINUOUS MODE

Context. One of the features of satellite communication systems is the advantageous use in them during the reception of the signal in the continuous mode of phase modulation of signals intended for the transmission of useful information. The use of this type of modulation requires solving the problem of estimating the carrier frequency of the signal. And the estimation itself is reduced to the problem of estimating the frequency of the maximum in the spectrum of a fragment of a sinusoidal signal against the background of additive Gaussian noise. The article considers the process of estimating the carrier frequency of a signal by a satellite communication system in a continuous mode according to the rule of maximum likelihood. Objective. Development of a procedure for estimating the carrier frequency of a signal received by a satellite communication system in a continuous mode according to the maximum likelihood rule. Method. The procedure proposed in the work and the algorithm developed on its basis allows to estimate the carrier frequency according to the rule of maximum likelihood, taking into account the conditions of uncertainty of all signal parameters by the satellite communication system in continuous mode. The results. For the purpose of practical introduction of the specified algorithm in operating schemes of satellite communication, schemes of its hardware realization are offered in work. To illustrate the ratio of the limits of the minimum limiting variance of the carrier frequency estimate, the paper presents dependencies that allow comparing the minimum limiting variance defined by the lower Cramer-Rao boundary and the minimum limiting variance determined taking into account all signal parameters. Conclusions. Analysis of these dependences showed that in real conditions the minimum dispersion of the carrier frequency of the signal according to the rule of maximum likelihood received by the satellite communication system in continuous mode with uncertainty of all signal parameters may differ significantly from the minimum dispersion obtained by applying the lower Kramer-Rao boundary. Prospective research, development and creation of algorithms and techniques aimed at estimating the carrier frequency at the minimum limiting variance in the conditions of uncertainty of all parameters of the received signal should be aimed at the maximum approximation of the minimum limiting variance of the estimated carrier frequency to the lower Cramer-Rao boundary to estimate the carrier frequency under conditions of certainty of other signal parameters.