A Physical Approach for Stochastic Modeling of TERO-based TRNG

International audienceSecurity in random number generation for cryptography is closely related to the entropy rate at the generator output. This rate has to be evaluated using an appropriate stochastic model. The stochastic model proposed in this paper is dedicated to the transition effect ring oscillator (TERO) based true random number generator (TRNG) proposed by Varchola and Drutarovsky in 2010. The advantage and originality of this model is that it is derived from a physical model based on a detailed study and on the precise electrical description of the noisy physical phenomena that contribute to the generation of random numbers. We compare the proposed electrical description with data generated in a 28 nm CMOS ASIC implementation. Our experimental results are in very good agreement with those obtained with both the physical model of TERO's noisy behavior and with the stochastic model of the TERO TRNG, which we also confirmed using the AIS 31 test suites

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This music score was submitted for the Kaleidoscope 2020 Call for Scores, an open access collaboration with the UCLA Music Library

The History of the Development and the Analysis of the Cipher Machine T-310/50 and the Procedure ARGON by the ZCO

This paper describes important aspects of the 10 years of development and the 18 years of security analysis of the cipher machine T-310/50 and the procedure ARGON by the Central Cipher Authority of the GDR. The threat model of the analysis is pictured. Examples of the security analysis of the cipher algorithm, machine, procedure and key management are provided. The focus is on the analysis of the operating functions of the T-310/50 (operating analysis), including the analysis of operating errors, as well as the analysis of the instruction manual for the cipher procedure ARGON. The possibilities of obtaining information by an attacker from traffic reconnaissance in general and decryption attacks in particular are assessed

The Stability of Silica Hydrosols Under the Influence of Polymer Adsorption

The stability of standardized, well dispersed silica (Aerosil). hydrosols at different pH has been studied using a self-constructed laser photosedimentometer. Ultrasonication was proved most suitable for providing reproducible standardized hydrosols, which were characterized by determining the viscosity/concentration dependence in a cylinder viscosimeter, the sedimentation coefficient in an analytical ultracentrifuge, the partial specific volume in an oscillating U-tube of a high precision density meter, the translational diffusion coefficient with a photon correlation spectrometer and the dimension and shape of the silica particles by transmission electron microscopy. The Aerosil hydrosols can be reproducibly flocculated with polyethyleneglycols of molar mass 6000 and 40 000, even in the absence of electrolyte at high pH, when the sol concentration is sufficiently high. Reproducibility necessitates standardized mixing procedures of sol and polymer. The laser-photosedimentometer provides suitable parameters for the characterization of the turbidity- and sedimentation behaviour of the flocculated sols. The effects of different mixing procedures have been tested and the influence of titration and mixing time, intensity and time of stirring can be analyzed quantitatively as well, as the relationships of the characterizing parameters on polymer coverage, molecular weight and silica concentration. From these dependences and by using additional rheological measurements it was possible to identify the classical model of polymer bridging as the most likely mechanism for the destabilizatio

Hierarchical Categories in Colored Searching

In colored range counting (CRC), the input is a set of points where each point is assigned a "color" (or a "category") and the goal is to store them in a data structure such that the number of distinct categories inside a given query range can be counted efficiently. CRC has strong motivations as it allows data structure to deal with categorical data. However, colors (i.e., the categories) in the CRC problem do not have any internal structure, whereas this is not the case for many datasets in practice where hierarchical categories exists or where a single input belongs to multiple categories. Motivated by these, we consider variants of the problem where such structures can be represented. We define two variants of the problem called hierarchical range counting (HCC) and sub-category colored range counting (SCRC) and consider hierarchical structures that can either be a DAG or a tree. We show that the two problems on some special trees are in fact equivalent to other well-known problems in the literature. Based on these, we also give efficient data structures when the underlying hierarchy can be represented as a tree. We show a conditional lower bound for the general case when the existing hierarchy can be any DAG, through reductions from the orthogonal vectors problem

”En Lille Hjælper på Vejen”: Et Kvalitativt Studie af Oplevelsen af en Kæledyrsrelation i Hverdagen hos Personer med Spiseforstyrrelse

Dette studie undersøger og diskuterer oplevelsen af en kæledyrsrelation, som en del af den hverdagslige recovery hos personer med spiseforstyrrelse. Dette er et tema, hvor der findes begrænset forskning fra tidligere. Med et fokus på menneske-dyr relationen, ønsker jeg at bygge bro mellem perspektiver på samspil mellem mennesker og natur (her forstået som mere-end-menneskelig-natur), perspektiver som er relevante indenfor blandt andet det friluftsfaglige felt, og et mere psykologisk perspektiv. Den konceptuelle linse for dette studie er et hverdagsperspektiv på recovery. Behandling af spiseforstyrrelser er ofte domineret af et medicinsk perspektiv. Forskere og behandlere opfordrer i dag til et bredere syn på recovery af psykiske lidelser, med et større fokus på individets egne erfaringer, og som inkluderer de sociale og individuelle processer i hverdagslivet. Det synes derfor relevant at rette fokus mod individets livsverden og belyse aspekter i hverdagslivet, som kan bidrage til højere grad af oplevet livskvalitet hos personer med psykiske lidelser. Forskning viser, at spiseforstyrrelser kan anses at have en relationel funktion hos individet (Fischette, 2017), der udgør en ”falsk sikker base” (Hochdorf et al., 2005). Samtidig peger forskning mod at båndet mellem kæledyr og ejere opfylder kriterier for et tilknytningsbånd (se f.eks. Kurdek, 2008, 2009). Jeg har derfor fundet det relevant at diskutere dette studies empiri ud fra et tilknytningsteoretisk rammeværk. Dette er et kvalitativt studie, som har undersøgt 7 kvinders oplevelse af en kæledyrsrelation knyttet til deres recovery i hverdagen. Metodologien bygger på et fortolkende fænomenologisk rammeværk, med det epistemologiske standpunkt at kundskab samskabes i mødet mellem forsker og den forskede, i en specifik kontekst. Mit eget refleksive engagement igennem hele forskningsprocessen har været vigtigt. Data er indsamlet med et semistruktureret interview og analyseret med en fortolkende fænomenologisk analyse (IPA). I analysen fandt jeg tre hovedtemaer: ”Ansvarsfølelse som motivation til at blive rask”, ”kæledyrsrelationen som et frirum” og ”kæledyrsrelationen som social relation”. Analysen af interviews holdt op mod teori tyder på at det følelsesmæssige bånd i kæledyrsrelationen oplevedes som noget betydningsfuldt hos deltagerne, i kraft af at være et trygt tilknytningsbånd. Tilknytningsbåndet forekom at være faciliteret af tilknytningskomponenten en sikker base og en omsorgskomponent, som begge understøttede deltagernes hverdagslige recovery-processer. Der syntes at findes andre komponenter i kæledyrsrelationen, som bidrog positivt til deltagernes recovery i hverdagen, uafhængigt af om der var et tilknytningsbånd eller ej. Relationen syntes at opleves som et frirum hos deltagerne, med plads til en tilstand af nærvær. Deltagerne beskrev, at aktiviteter og samspil med kæledyrene, hjalp dem med at trække fokus væk fra negative tanker og følelser, ud mod kæledyret og omgivelserne sanseindtryk. Samspil og nonverbal kommunikation i kæledyrsrelationen syntes videre at bidrage til øget bevidsthed om indre fornemmelser hos flere deltagere. Dette var specielt fremtrædende hos deltagerne med heste, og i mindre grad hos deltagerne med hund. Dette syntes ikke at være aktuelt hos deltageren med kat som kæledyr. Kæledyrene forekom at mindske den emotionelle ensomhed i deltagernes hverdag. Samtidig fortalte flere deltagere at kæledyret blev en social facilitator i interpersonelle relationer. Den daglige interaktion i kæledyrsrelationerne var karakteriseret af ”små ting” som gav deltagerne oplevelser af glæde, mening og bekræftelse i hverdagen. Deltagernes kæledyrsrelationer kan derved argumenteres at indeholde healing interpersonal patterns (HIPs), som bidrog positivt til deres hverdagslige recovery. Det er vigtigt at understrege, at samvær med kæledyr ikke nødvendigvis helbreder eller ”erstatter” spiseforstyrrelsen. Empirien fra dette studie peger mod at kæledyret nærmere kan anses som ”en lille hjælper på vejen” som en deltager beskrev sin hund, som bidrager til større grad af oplevet trivsel og mening i deltagernes hverdag

The Adsorption of Macromolecules on Solid/Liquid Interfaces

The main problem in the investigations of polymer adsorption is clearing up the structu,re of the adsorbed layer, and the conformation of the adsorbed macromolecule. In order to get direct informations of the adsorbed macromolecule, calorimetric, ellipsometric and ir-spectrometric measurements are used. The structure of the polymer layer of the investigated polymer-solvent-adsorbens system is characterized by the adsorbed amount, the number of adhesive segments, the adsorption enthalpy and by the thickness and the concentration of the adsorbed layer. All this parameters are dependent on the structure of the macromolecule in solution, the degree of coverage of the adsorbent surface, the enthalpy balance and the surface density of the adhesive sites on the adsorbens. The reversibility of the adsorption is influenced by the conformation of the adsorbed macromolecule and by the molecular weight