Authentication under Constraints

Authentication has become a critical step to gain access to services such as on-line banking, e-commerce, transport systems and cars (contact-less keys). In several cases, however, the authentication process has to be performed under challenging conditions. This thesis is essentially a compendium of five papers which are the result of a two-year study on authentication in constrained settings. The two major constraints considered in this work are: (1) the noise and (2) the computational power. For what concerns authentication under noisy conditions, Paper A and Paper B ad- dress the case in which the noise is in the authentication credentials. More precisely, the aforementioned papers present attacks against biometric authentication systems, that exploit the inherent variant nature of biometric traits to gain information that should not be leaked by the system. Paper C and Paper D study proximity- based authentication, i.e., distance-bounding protocols. In this case, both of the constraints are present: the possible presence of noise in the channel (which affects communication and thus the authentication process), as well as resource constraints on the computational power and the storage space of the authenticating party (called the prover, e.g., an RFID tag). Finally, Paper E investigates how to achieve reliable verification of the authenticity of a digital signature, when the verifying party has limited computational power, and thus offloads part of the computations to an untrusted server. Throughout the presented research work, a special emphasis is given to privacy concerns risen by the constrained conditions

Decarbonizing the cold chain: Long-haul refrigerated deliveries with on-board photovoltaic energy integration

Decarbonizing the cold chain is a priority for sustainability due to the increasing demand for chilled/frozen food and pharmaceutics. Refrigerated transport requires additional fuel for refrigeration other than for traction. Photovoltaic panels on the vehicle rooftop, a battery bank, and a power conversion system can replace the diesel engine driving the transport refrigerated unit. In long-haul deliveries, vehicles cross zones with different climate conditions, which affect both refrigeration requirements and photovoltaic energy conversion. Mandatory driver\u2019s breaks and rest also affect delivery timing and energy consumption. A multiperiod, multizone optimization model is developed to size the onboard photovoltaic system, based on features of the delivery tour. The model is applied to a palletized chilled food delivery from North-Eastern Italy, showing a payback time of around four years, which can drop under two years for expected reduction of component costs. Economic and environmental performances can be increased by also allowing refrigerated products on-board during the return journey, leading to more fuel savings. Photovoltaic-integrated long-haul delivery for frozen products is not convenient at current market costs. Different climate conditions are tested, showing the model ability to act as a decision support tool to foster renewable energy penetration into the cold chain

Relationship between NOX4 level and angiotensin II signaling in Gitelman's syndrome. Implications with hypertension

Recent evidence showed that endogenous nicotinamide adenine dinucleotide phosphate-oxidase 4 (NOX4) may exert a protective role on the cardiovascular system inducing vasodilation, reduction of blood pressure, and anti-proliferative actions. However, the functional significance of NOX4 in the cardiovascular system in humans remains elusive. Mononuclear cell levels of NOX4 were assessed by immunoblotting in 14 Gitelman's patients (GS), a unique human model of endogenous Ang II signaling antagonism and activation of anti-atherosclerotic and anti-remodeling defenses, and compared to 11 untreated essential hypertensive patients as well as to 11 healthy normotensive subjects. The association between NOX4 and its effector heme oxygenase (HO-1) (sandwich immunoassay) was also evaluated. NOX4 protein levels were decreased in hypertensive patients as compared to both GS and healthy subjects (1.06±0.31 AU vs. 1.76±0.54, P=0.002 and vs. 1.61±0.54, P=0.018, respectively). NOX4 protein level did not differ between GS and healthy subjects. HO-1 levels were increased in GS patients as compared to both hypertensive patients and healthy subjects (8.65±3.08 ng/ml vs 3.70±1.19, P<0.0001, and vs 5.49±1.04, P=0.008, respectively. NOX4 levels correlate with HO-1 levels only in GS (r(2)=0.63; P=0.001), (r(2)=0.088; P=ns, in hypertensive patients and r(2)=0.082; P=ns, in healthy subjects). Our findings show that NOX4 and its effector HO-1 are reduced in hypertensive patients compared to GS patients, a human model opposite to hypertension. Although the functional significance of NOX4 needs further clarification, our preliminary data in a unique human model of anti-atherosclerotic and anti-remodeling defenses activation, highlight the potentially protective role of NOX4 in the human cardiovascular system

How Can Ozone and Relative Humidity Affect Artists’ Alkyd Paints? A FT-IR and Py-GC/MS Systematic Study

Knowledge of the chemical–physical reactions that determine the main degradation behaviour of artists’ alkyd paints represents one of the main problems within the museum exhibitions. The collection and interpretation of these data on degradation phenomena, especially after ozone exposure at different relative humidity values, can be useful for their conservation needs. Therefore, a systematic investigation of these materials may help achieve this goal. Firstly, surface-level identification of the main functional groups of ad hoc created and aged alkyd paints was performed using attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR). Subsequently, these paints were investigated by pyrolysis–gas chromatography and mass spectrometry (Py–GC/MS), allowing for precise bulk identification of the organic compounds before and after accelerated ageing. A first successful attempt to provide quantitative Py–GC/MS data on alkyd-based paints is here presented and discussed. Comparing the results, it was possible to obtain new insights into the degradation behaviour of alkyd paints when exposed to ozone, allowing us to devise specific preventive and conservation strategies for these artistic materials

Be More and be Merry: Enhancing Data and User Authentication in Collaborative Settings

Cryptography is the science and art of keeping information secret to un-intended parties. But, how can we determine who is an intended party and who is not? Authentication is the branch of cryptography that aims at confirming the source of data or at proving the identity of a person. This Ph.D. thesis is a study of different ways to perform cryptographic authentication of data and users. The main contributions are contained in the six papers included in this thesis and cover the following research areas: (i) homomorphic authentication; (ii) server-aided verification of signatures; (iii) distance-bounding authentication; and (iv) biometric authentication. The investigation flow is towards collaborative settings, that is, application scenarios where different and mutually distrustful entities work jointly for a common goal. The results presented in this thesis allow for secure and efficient authentication when more entities are involved, thus the title “be more and be merry”. Concretely, the first two papers in the collection are on homomorphic authenticators and provide an in-depth study on how to enhance existing primitives with multi- key functionalities. In particular, the papers extend homomorphic signatures and homomorphic message authentication codes to support computations on data authenticated using different secret keys. The third paper explores signer anonymity in the area of server-aided verification and provides new secure constructions. The fourth paper is in the area of distance-bounding authentication and describes a generic method to make existing protocols not only authenticate direct-neighbors, but also entities located two-hop away. The last two papers investigate the leakage of information that affects a special family of biometric authentication systems and how to combine verifiable computation techniques with biometric authentication in order to mitigate known attacks

Theory of mind and school achievement: the mediating role of social competence

Recent findings have highlighted the importance of children's social understanding – specifically their reasoning about beliefs and emotions – for school achievement. However, little is known about the processes that may account for such a relationship. In this longitudinal study we examined the role of children's social competence (as indexed by peer relationships and social skills), using a multi-informant and multi-indicator approach. We followed 73 children during the transition to primary school, gathering data at three time points: Time 1 (age 5), Time 2 (age 7) and Time 3 (age 8). Structural equation modelling showed that Time 1 social understanding predicted Time 2 social competence, which in turn predicted Time 3 school achievement, independently of verbal ability. Moreover, social competence mediated the relationship between early social understanding and later school achievement. Theoretical and practical implications of these findings are discussed

Data Fusion Approach to Simultaneously Evaluate the Degradation Process Caused by Ozone and Humidity on Modern Paint Materials

The knowledge of the atmospheric degradation reactions affecting the stability of modern materials is still of current interest. In fact, environmental parameters, such as relative humidity (RH), temperature, and pollutant agents, often fluctuate due to natural or anthropogenic climatic changes. This study focuses on evaluating analytical and statistical strategies to investigate the degradation processes of acrylic and styrene-acrylic paints after exposure to ozone (O3) and RH. A first comparison of FTIR and Py-GC/MS results allowed to obtain qualitative information on the degradation products and the influence of the pigments on the paints’ stability. The combination of these results represents a significant potential for the use of data fusion methods. Specifically, the datasets obtained by FTIR and Py-GC/MS were combined using a low-level data fusion approach and subsequently processed by principal component analysis (PCA). It allowed to evaluate the different chemical impact of the variables for the characterization of unaged and aged samples, understanding which paint is more prone to ozone degradation, and which aging variables most compromise their stability. The advantage of this method consists in simultaneously evaluating all the FTIR and Py-GC/MS variables and describing common degradation patterns. From these combined results, specific information was obtained for further suitable conservation practices for modern and contemporary painted films

Quanti-qualitative evaluation of pectins in the dietary fibre of 24 foods

The dietary fibre of 24 foods was analysed for its proportions of insoluble and soluble (SDF) fractions and for its contentof high methoxyl pectins (HM), low methoxyl pectins (LM) and protopectin. The fractional extraction and quantitativedetermination of pectins were performed on the total dietary fibre residue, following the procedure suggested byRobertson (1979). Total pectin content (TP), calculated as sum of the three fractions, ranged from 2.4 to 49.8 g/kg ofdry matter. The variation coefficient of TP measurements repeated on the same foods were, on average, 2%. Total pectincontent was 49.8 g/kg DM in dried beet pulp and averaged 33.8+_0.3 g/kg DM in fruits and vegetables, 13.2+_8.4 g/kgDM in legumes and tubers and only 2.8+_0.5 g/kg DM in cereals. HM fraction prevailed in apple and pear samples (>40%of TP), while LM and protopectin largely prevailed in legumes and vegetables. A strong variability among foods was foundfor the TP/SDF ratio. In general, within each food category, increasing levels of SDF were associated with decreasing valuesof TP/SDF ratio. Since many foods contain low amounts of pectins, care in the development of calibration curves forspectrophotometric reading is required. Finally, the whole procedure for pectin extraction and quantification on dietaryfibre of food is very complex and time-consuming