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

HB+DB: Mitigating Man-in-the-Middle Attacks against HB+ with Distance Bounding.

Authentication for resource-constrained devices is seen as one of the major challenges in current wireless communication networks. The HB+ protocol performs device authentication based on the learning parity with noise (LPN) problem and simple computational steps, that renders it suitable for resource-constrained devices such as radio frequency identification (RFID) tags. However, it has been shown that the HB+ protocol as well as many of its variants are vulnerable to a simple man-in-the-middle attack. We demonstrate that this attack could be mitigated using physical layer measures from distance-bounding and simple modifications to devices’ radio receivers. Our hybrid solution (HB+DB) is shown to provide both effective distance-bounding using a lightweight HB+-based response function, and resistance against the man-in-the-middle attack to HB+. We provide experimental evaluation of our results as well as a brief discussion on practical requirements for secure implementation

Security and privacy in RFID systems

Vu que les tags RFID sont actuellement en phase de large déploiement dans le cadre de plusieurs applications (comme les paiements automatiques, le contrôle d'accès à distance, et la gestion des chaînes d approvisionnement), il est important de concevoir des protocoles de sécurité garantissant la protection de la vie privée des détenteurs de tags RFID. Or, la conception de ces protocoles est régie par les limitations en termes de puissance et de calcul de la technologie RFID, et par les modèles de sécurité qui sont à notre avis trop forts pour des systèmes aussi contraints que les tags RFID. De ce fait, on limite dans cette thèse le modèle de sécurité; en particulier, un adversaire ne peut pas observer toutes les interactions entre tags et lecteurs. Cette restriction est réaliste notamment dans le contexte de la gestion des chaînes d approvisionnement qui est l application cible de ce travail. Sous cette hypothèse, on présente quatre protocoles cryptographiques assurant une meilleure collaboration entre les différents partenaires de la chaîne d approvisionnement. D abord, on propose un protocole de transfert de propriété des tags RFID, qui garantit l authentification des tags en temps constant alors que les tags implémentent uniquement des algorithmes symétriques, et qui permet de vérifier l'authenticité de l origine des tags. Ensuite, on aborde le problème d'authenticité des produits en introduisant deux protocoles de sécurité qui permettent à un ensemble de vérificateurs de vérifier que des tags sans capacité de calcul ont emprunté des chemins valides dans la chaîne d approvisionnement. Le dernier résultat présenté dans cette thèse est un protocole d appariement d objets utilisant des tags sans capacité de calcul , qui vise l automatisation des inspections de sécurité dans la chaîne d approvisionnement lors du transport des produits dangereux. Les protocoles introduits dans cette thèse utilisent les courbes elliptiques et les couplages bilinéaires qui permettent la construction des algorithmes de signature et de chiffrement efficaces, et qui minimisent donc le stockage et le calcul dans les systèmes RFID. De plus, la sécurité de ces protocoles est démontrée sous des modèles formels bien définis qui prennent en compte les limitations et les contraintes des tags RFID, et les exigences strictes en termes de sécurité et de la protection de la vie privée des chaines d approvisionnement.While RFID systems are one of the key enablers helping the prototype of pervasive computer applications, the deployment of RFID technologies also comes with new privacy and security concerns ranging from people tracking and industrial espionage to produ ct cloning and denial of service. Cryptographic solutions to tackle these issues were in general challenged by the limited resources of RFID tags, and by the formalizations of RFID privacy that are believed to be too strong for such constrained devices. It follows that most of the existing RFID-based cryptographic schemes failed at ensuring tag privacy without sacrificing RFID scalability or RFID cost effectiveness. In this thesis, we therefore relax the existing definitions of tag privacy to bridge the gap between RFID privacy in theory and RFID privacy in practice, by assuming that an adversary cannot continuously monitor tags. Under this assumption, we are able to design sec ure and privacy preserving multi-party protocols for RFID-enabled supply chains. Namely, we propose a protocol for tag ownership transfer that features constant-time authentication while tags are only required to compute hash functions. Then, we tackle the problem of product genuineness verification by introducing two protocols for product tracking in the supply chain that rely on storage only tags. Finally, we present a solution for item matching that uses storage only tags and aims at the automation of safety inspections in the supply chain.The protocols presented in this manuscript rely on operations performed in subgroups of elliptic curves that allow for the construction of short encryptions and signatures, resulting in minimal storage requirements for RFID tags. Moreover, the privacy and the security of these protocols are proven under well defined formal models that take into account the computational limitations of RFID technology and the stringent privacy and security requirements of each targeted supply chain application.PARIS-Télécom ParisTech (751132302) / SudocSudocFranceF

Object detection in dual-band infrared

Dual-Band Infrared (DBIR) offers the advantage of combining Mid-Wave Infrared (MWIR) and Long-Wave Infrared (LWIR) within a single field-of-view (FoV). This provides additional information for each spectral band. DBIR camera systems find applications in both military and civilian contexts. This work introduces a novel labeled DBIR dataset that includes civilian vehicles, aircraft, birds, and people. The dataset is designed for utilization in object detection and tracking algorithms. It comprises 233 objects with tracks spanning up to 1,300 frames, encompassing images in both MW and LW. This research reviews pertinent literature related to object detection, object detection in the infrared spectrum, and data fusion. Two sets of experiments were conducted using this DBIR dataset: Motion Detection and CNNbased object detection. For motion detection, a parallel implementation of the Visual Background Extractor (ViBe) was developed, employing ConnectedComponents analysis to generate bounding boxes. To assess these bounding boxes, Intersection-over-Union (IoU) calculations were performed. The results demonstrate that DBIR enhances the IoU of bounding boxes in 6.11% of cases within sequences where the camera’s field of view remains stationary. A size analysis reveals ViBe’s effectiveness in detecting small and dim objects within this dataset. A subsequent experiment employed You Only Look Once (YOLO) versions 4 and 7 to conduct inference on this dataset, following image preprocessing. The inference models were trained using visible spectrum MS COCO data. The findings confirm that YOLOv4/7 effectively detect objects within the infrared spectrum in this dataset. An assessment of these CNNs’ performance relative to the size of the detected object highlights the significance of object size in detection capabilities. Notably, DBIR substantially enhances detection capabilities in both YOLOv4 and YOLOv7; however, in the latter case, the number of False Positive detections increases. Consequently, while DBIR improves the recall of YOLOv4/7, the introduction of DBIR information reduces the precision of YOLOv7. This study also demonstrates the complementary nature of ViBe and YOLO in their detection capabilities based on object size in this data set. Though this is known prior art, an approach using these two approaches in a hybridized configuration is discussed. ViBe excels in detecting small, distant objects, while YOLO excels in detecting larger, closer objects. The research underscores that DBIR offers multiple advantages over MW or LW alone in modern computer vision algorithms, warranting further research investment

Experimental and numerical analysis of tensile membrane action in reinforced concrete slabs in the framework of structural robustness

As a consequence of several structural failures in the last decades, the European Standard EN 1990 (2002) ‘Basis of structural design’ incorporated the following requirement with respect to robustness: “A structure shall be designed and executed in such a way that it will not be damaged by events such as explosion, impact and the consequence of human errors to an extent disproportionate to the original cause”. In addition, the European Standard EN 1991-1-7 (2006) ‘Actions on structures – Part 1-7: Accidental actions’ points to strategies to enhance structural robustness, emphasising amongst others the favourable contribution of developing alternate load paths in case of abnormal loading events. The investigations reported in the present thesis aim for a better understanding of the alternate load path provided by the transition from a flexural to a tensile load transfer. In particular, the load transfer provided by tensile membrane action developing at very large displacements after a support removal scenario and, subsequently, excessive loading is investigated. It is widely appreciated that this tensile membrane behaviour has a positive effect on the structural behaviour. The ultimate limit state behaviour for tensile membrane action developing in slabs, however, is largely unknown due to the limited amount of experimental largescale investigations. Based on an extensive literature review, an experimental program has been elaborated in order to investigate tensile membrane action developing in a restrained one-way concrete slab. A unique test set-up has been developed allowing a loading test on a four-span reinforced concrete slab strip under longitudinal elongation restraint into the region of large deflections. The tested slabs were 140 mm or 160 mm thick and 1800 mm wide with a geometric reinforcement ratio of about 0.5 %. The total length of each specimen was 14.3 m, whereas the distance between the inner supports and the central support was 4 m. These spans changed to one span of 8 m between the inner supports after the controlled removal of the central support, thus simulating an accidental event.Further, also a testing procedure was elaborated, consisting of 3 phases (i.e. loading until an arbitrary preloading level, removal of the central support and loading until failure). During the first phase, the load was gradually increased up to the preloading level for the situation where the central support was still present. Subsequently, the slab was unloaded. In a second phase, the central support of the specimens was gradually removed in order to simulate a failure of the support and to obtain valuable data regarding the robustness of the specimens. Accordingly, the two inner spans of 4 m each, changed to a single span of 8 m. The specimens were allowed to bend progressively in the central span of the slab, resulting in a redistribution of stresses and the development of an alternate load path distributing the emerging forces to the remaining supports. Finally, in the third phase, the load was applied again by two line loads in a displacement controlled manner until failure. With increasing vertical deflections of the specimens the slabs’ ends started to move inwards provoking a significant increase in the loadcarrying capacity due to emerging tensile membrane forces established by a horizontal restraining system. In total three different tests on slab strips with horizontal restraint were performed. In case of slab 1, the longitudinal top and bottom flexural reinforcement was continuous over the entire length of the specimen. Hence, no reinforcement curtailing was applied. Further, a second specimen featuring a realistic reinforcement curtailment was tested. In case of slab 3 the longitudinal flexural reinforcement was curtailed similar to slab 2, but the thickness of the slab was reduced from 160 mm to 140 mm. In all three tests, tensile membrane action was activated during the third phase of testing, significantly increasing the load carrying capacity of the specimen under investigation. During the tests, manual measurements were executed after each successive increase of the load or displacement, comprising dial gauges, crack widths measurements and DEMEC measurements. Further, around 60 digital channels were recording the digital measurements comprising displacements, horizontal (membrane) and vertical (reaction) load cell forces and strain measurements with stirrups. Each tested slab strip was exposed to three distinct stages: an elastic, plastic and tensile membrane stage. The development of displacements, strain measurements as well as the horizontal forces within this investigation confirmed a load transfer process from an elastic bending mechanism, over a plastic stage towards a tensile membrane mechanism controlled by tension. As tensile membrane forces developed, the load bearing capacity was able to increase until approximately 3 times the service load for slab 1 and 2.6 times for slab 2 (despite the removal of the central support). For slab 3 the ultimate collapse load even amounted to about 3.6 times the service load. Hence, the importance of quantifying this additional bearing capacity became clear, especially in robustness analysis, as otherwise one disregards an inherently available and very large additional safety. The test results provide a unique set of detailed experimental data (crack widths, deformations, rotation angles, displacements, etc.) allowing for a detailed analysis and refined comparisons with respect to the structural response under tensile membrane action as well as regarding the failure criteria.Finite element modelling was used to simulate the structural behaviour of oneway slabs under large deformations and tensile membrane actions. On the basis of the experimental findings, the numerical model was validated with special attention to material models, mesh definition and boundary conditions accounting for highly non-linear material performances as well as geometrical non-linear behaviour. In summary, the load-displacement curves until the failure of the top reinforcement bars, displacements, rotation angles, the development of strains and tensile membrane forces were calculated within a reasonable tolerance and showed good agreement with the laboratory tests. As such, it is demonstrated that the developed finite element model is a suitable tool being capable to predict the structural response under tensile membrane forces. By means of this developed finite element model, a parametric study was conducted. In this study the influence of several geometries (various span lengths, thicknesses and reinforcement ratios), material assumptions (various steel qualities and ultimate reinforcement strains) and boundary conditions are investigated and discussed. A literature study with respect to analytical models for tensile membrane action was performed serving as a starting point for the analytical investigation. On the basis of the standard plastic theory an analytical model is proposed firstly considering perfectly restrained edges. The loading response, the formation of tensile membrane action and the failure load is accounted for. Further, the proposed method was applied and refined in order to simulate the structural behaviour of the conducted slab experiments by incorporating non-linear horizontal movements of the restraining system. The calculation results were compared with numerical and experimental findings and the analysis results show good agreement. In the presented PhD thesis it is demonstrated by means of experimental, numerical as well as analytical investigations that the development of tensile membrane behaviour as a result of horizontal edge restraint is capable of generating a considerable strength reserve significantly increasing the loading response of one-way reinforced concrete slabs when very large deformations occur. The insights gained from these investigations give strong evidence of the beneficial contribution of tensile membrane action to the loading capacity and robustness of concrete structures in accidental load situations. The developed numerical and analytical calculation techniques are shown to be feasible tools not only to quantify the loading response corresponding to the experimentally observed ultimate limit state behaviour but also to predict the structural response under tensile membrane action for other boundary conditions and material characteristics serving as a general calculation framework to include tensile membrane action in conventional design when robustness is considered

Mobile Ad-Hoc Networks

Being infrastructure-less and without central administration control, wireless ad-hoc networking is playing a more and more important role in extending the coverage of traditional wireless infrastructure (cellular networks, wireless LAN, etc). This book includes state-of the-art techniques and solutions for wireless ad-hoc networks. It focuses on the following topics in ad-hoc networks: vehicular ad-hoc networks, security and caching, TCP in ad-hoc networks and emerging applications. It is targeted to provide network engineers and researchers with design guidelines for large scale wireless ad hoc networks

Integrated Applications of Geo-Information in Environmental Monitoring

This book focuses on fundamental and applied research on geo-information technology, notably optical and radar remote sensing and algorithm improvements, and their applications in environmental monitoring. This Special Issue presents ten high-quality research papers covering up-to-date research in land cover change and desertification analyses, geo-disaster risk and damage evaluation, mining area restoration assessments, the improvement and development of algorithms, and coastal environmental monitoring and object targeting. The purpose of this Special Issue is to promote exchanges, communications and share the research outcomes of scientists worldwide and to bridge the gap between scientific research and its applications for advancing and improving society

Wide-Angle Multistatic Synthetic Aperture Radar: Focused Image Formation and Aliasing Artifact Mitigation

Traditional monostatic Synthetic Aperture Radar (SAR) platforms force the user to choose between two image types: larger, low resolution images or smaller, high resolution images. Switching to a Wide-Angle Multistatic Synthetic Aperture Radar (WAM-SAR) approach allows formation of large high-resolution images. Unfortunately, WAM-SAR suffers from two significant implementation problems. First, wavefront curvature effects, non-linear flight paths, and warped ground planes lead to image defocusing with traditional SAR processing methods. A new 3-D monostatic/bistatic image formation routine solves the defocusing problem, correcting for all relevant wide-angle effects. Inverse SAR (ISAR) imagery from a Radar Cross Section (RCS) chamber validates this approach. The second implementation problem stems from the large Doppler spread in the wide-angle scene, leading to severe aliasing problems. This research effort develops a new anti-aliasing technique using randomized Stepped-Frequency (SF) waveforms to form Doppler filter nulls coinciding with aliasing artifact locations. Both simulation and laboratory results demonstrate effective performance, eliminating more than 99% of the aliased energy

Winona Daily News

https://openriver.winona.edu/winonadailynews/2322/thumbnail.jp