Secret sharing is critical to most applications making use of security and remains one of the most challenging research areas in modern cryptography. In this thesis, we propose a novel efficient multi-secret sharing scheme based on the Chinese remainder theorem (CRT) with two verification methods, while the previous works are mostly based on the Lagrange polynomial. Key management schemes play an important role in communication security in Wireless Sensor Networks (WSNs). While the previous works mainly targeting on two different types of WSNs: distributed and hieratical, in this thesis, we propose our flexible WSN key management scheme, which is based on (n,t,n) multi-secret sharing technique, to provide a key management solution for heterogeneous architecture. The powerful key managers are responsible for most of the communicational and computational workload. They can provide Peer-to-Peer pair-wise keys for a pair of sensors to establish a secure communication session, and in the same time, they can also form communication clusters as cluster heads according to different application requirements. Internet of Things (IoT) becomes more and more popular and practical in recent years. Considering the diversity of the devices and the application scenarios, it is extremely hard to couple two devices or sub-networks with different communication and computation resources. In this thesis, we propose novel key agreement schemes based on (n,t,n) multi-secret sharing techniques for IoT in order to achieve light weighted key exchange while using Host Identity Protocol (HIP). We refer the new schemes as HIP-MEXs with different underlying multi-secret sharing techniques. We analyzed the computational and communication costs of the extremely resource constrained device which is referred to as Initiator, and CRT based HIP-MEX successfully outsource the heavy workload to the proxy, which are considered more powerful, when establishing new secret key.

Dans cette étude, nous avons cherché à caractériser le profil linguistique et le développement d’une population portugaise d’enfants ayant une perturbation spécifique du développement du langage (TSDL) et à analyser, dans le contexte de la théorie de l’attachement, la façon dont ces enfants porteurs de TSDL utilisent la mère comme base sûre, en les comparant à des enfants sans perturbation du langage. D’un autre côté, nous avons étudié la valeur prédictive de l’attachement et des variables développementales dans les compétences linguistiques des enfants. Nous avons retenu comme sujets de notre recherche, 83 dyades mère/enfant, les enfants étant âgés de 4 /5 ans, partagés en deux groupes. À travers les diverses mesures du langage et du AQS (Waters, 1995), il a été possible de vérifier que ces enfants :1) présentaient à l’âge mental propre de la maternelle (préscolaire), des changements sévères du langage, bien que leurs profils soient très hétérogènes ;2) étaient surtout des garçons, d’un ratio de 3:1 ; 3) révèlent une qualité de sécurité de l’attachement à la mère, inférieure comparativement à leurs pairs sans changement au niveau du langage, ainsi que moins de comportements d’attachement, telles que l’interaction douce, la proximité et le contact physique avec la mère.Nous avons également vérifié que l’attachement et les variables de consommation maternelle de tabac pendant la grossesse, la relation avec les amis et les antécédents familiaux de perturbation du langage sont des prédicteurs des difficultés linguistiques de ces enfants, ainsi que des durées d’acquisition du langage, ce qui explique une variance entre 7% et 21%. / This study aims to characterize the linguistic and developmental profile of a population of Portuguese-speaking children with specific language impairment (SLI) and analyze, within the context of attachment theory, how the SLI child uses his mother as a secure base, compared to children without language disorders. In the other eAs a final point, we tried to study the predictive value of attachment and developmental variables in the language skills of children. The participants of our study were 83 mother-child dyads (children aged 4-5 years), divided into two groups. Through various measures of language and AQS (Waters, 1995), we found that these children: 1) present, in pre-school age, severe alterations of language, though their profiles are very heterogeneous; 2) are mostly boys, with a ratio of 3:1; 3) show a lower quality of attachment security, when compared with their peers without language alterations, as well as less attachment behaviors, such as smooth interaction, proximity and physical contact with the mother. It was also found that attachment and tobacco use, relationship with friends and family background are predictors of the linguistic difficulties of these children, as well as of language acquisition timing, explaining 7% to 21% of the variance.

Mobile Ad hoc Networks (MANETs) are re-emerging as a popular networking facility for wireless device users. A growing number of diversified applications are now accessible via wireless devices. The different applications may have different Quality of Service (QoS) requirements, which may better be satisfied by using different routing methods or metric types. Existing ad hoc network routing solutions do not consider various application-level requirements when making a routing decision. They typically make routing decisions based upon limited information acquired at the network layer. Most of the existing routing protocols make use of a single routing metric. Using a single metric type and/or information, only acquired at the network layer may not be able to accommodate different QoS requirements, imposed by diversified user-level applications or application-level data types.The aim of this thesis is to design an efficient routing function for ad hoc networks while at the same time satisfying users‟ and/or applications‟ QoS and security requirements. To achieve this, the thesis investigates and specifies routing requirements that could best support application-level QoS and security requirements in MANETs. It also investigates and critically analyses the state of the art in MANET routing, and the mechanisms used for protecting the routing functions. To overcome the weaknesses and advance the state of the art in MANET routing, this thesis proposes two major solutions. The first solution is the Secure ETX (SETX) routing protocol. It is a secure routing solution that can provide routing functions efficiently in malicious MANET environment. The SETX protocol provides a security mechanism to counter black hole attacks in MANETs on the ETX metric acquisition process. Simulation studies have been carried out and discussed in the thesis. Simulation results show that the SETX protocol can provide a marked improvement in network performances in the presence of black hole attacks, and it can do so with a negligible level of additional overhead.The second solution is a novel routing decision making called the Flexible Routing Decision (FRD) framework. The FRD framework supports routing decision making by using multiple metric types (i.e. multi-criteria routing decision making) and uses a cross-layer approach to support application-level QoS requirements. This allows users to use different routing metrics types, making the most appropriate routing decision for a given application. To accommodate the diversified application-level QoS requirements, multiple routing metric types have been identified and interpreted in the FRD framework design. The FRD framework has overcome some weaknesses exhibited by existing single metric routing decision making, used in MANETs. The performance of a routing decision making of FRD is also evaluated using NS2 simulation package. Simulation results demonstrate that the FRD framework outperforms the existing routing decision making methods.

Dans cette thèse, nous étudions les preuves à divulgation nulle de connaissance, une primitive cryptographique permettant de prouver une assertion en ne révélant rien de plus que sa véracité, et leurs applications au calcul sécurisé. Nous introduisons tout d’abord un nouveau type de preuves à divulgation nulle, appelées arguments implicites à divulgation nulle, intermédiaire entre deux notions existantes, les preuves interactives et les preuves non interactives à divulgation nulle. Cette nouvelle notion permet d’obtenir les mêmes bénéfices en terme d’efficacité que les preuves non-interactives dans le contexte de la construction de protocoles de calcul sécurisé faiblement interactifs, mais peut être instanciée à partir des mêmes hypothèses cryptographiques que les preuves interactives, permettant d’obtenir de meilleures garanties d’efficacité et de sécurité. Dans un second temps, nous revisitons un système de preuves à divulgation nulle de connaissance qui est particulièrement utile dans le cadre de protocoles de calcul sécurisé manipulant des nombres entiers, et nous démontrons que son analyse de sécurité classique peut être améliorée pour faire reposer ce système de preuve sur une hypothèse plus standard et mieux connue. Enfin, nous introduisons une nouvelle méthode de construction de systèmes de preuves à divulgation nulle sur les entiers, qui représente une amélioration par rapport aux méthodes existantes, tout particulièrement dans un modèle de type client-serveur, où un client à faible puissance de calcul participe à un protocole de calcul sécurisé avec un serveur à forte puissance de calcul. / In this thesis, we study zero-knowledge proofs, a cryptographic primitive that allows to prove a statement while yielding nothing beyond its truth, and their applications to secure computation. Specifically, we first introduce a new type of zero-knowledge proofs, called implicit zero-knowledge arguments, that stands between two existing notions, interactive zeroknowledge proofs and non-interactive zero-knowledge proofs. Our new notion provides the same efficiency benefits than the latter when used to design roundefficient secure computation protocols, but it can be built from essentially the same cryptographic assumptions than the former, which allows to get improved efficiency and security guarantees. Second, we revisit a zero-knowledge proof system that is particularly useful for secure computation protocols manipulating integers, and show that the known security analysis can be improved to base the proof system on a more wellstudied assumption. Eventually, we introduce a new method to build zero-knowledge proof systems over the integers, which particularly improves over existing methods in a client-server model, where a weak client executes a secure computation protocol with a powerful server.

Two studies were conducted to present two new theoretical constructs based on narcissistic personality and Daoist water-like personality research. Narcissistic group orientation (NGO) was developed to incorporate both the grandiose and vulnerable expressions of narcissism into a group-oriented social variable. NGO is pathological group orientation with two distinct expressions that share a common etiology in social identity monopolization. The conditions that promote social identity monopolization and ultimately increase the salience of the particular self-category, differ amongst the grandiose and vulnerable expressions of NGO. The grandiose expression increases salience of a particular self-category to facilitate opportunistic use for self-enhancement, while the vulnerable expression increases salience of a particular self-category to facilitate threat detection and avoidance. Water-like group orientation (WGO) was developed to provide a measure of secure in-group positivity which is in contrast to defensive in-group positivity. WGO is a prosocial group orientation that is based on the Daoist principle of wuwei (non-action) or underacting which is conceived here as a lack of desire for control. Study 1 aimed to provide support for the factor structure of the newly developed scales and provide evidence of validity. The results of confirmatory factor analyses in Study 1 and Study 2 supported a two-factor NGO model and a two-factor WGO model. The two-factor NGO model is made up of a grandiose narcissistic group orientation (GNGO) factor and a vulnerable narcissistic group orientation (VNGO) factor. WGO Factor 1 (WGOF1) is an in-group confidence and satisfaction factor, and WGO Factor 2 (WGOF2) is an out-group respect and altruism factor. Study 1 also gathered evidence of convergent validity for both the NGO and WGO constructs. Both GNGO and VNGO exhibited positive correlations with social dominance orientation and blind patriotism, and negligible correlations with constructive patriotism. WGOF1 exhibited positive correlations with social dominance orientation and blind patriotism, and a negligible correlation with constructive patriotism. WGOF2 exhibited negative correlations with social dominance orientation and blind patriotism, and a positive correlation with constructive patriotism. Study 2 sought to gather support for the factor structure of NGO and WGO once again and to examine the relationship between GNGO, VNGO, WGOF1, and WGOF2 with a multicomponent measure of in-group identification that includes solidarity, satisfaction, centrality, self-stereotyping, and in-group homogeneity. GNGO, VNGO, and WGOF1 were positively related to all five in-group identification components, while WGOF2 was unrelated to all five in-group identification components. The NGO and WGO scales may be used to study groups who are experiencing acute or ongoing intergroup conflict, intense scrutiny, or aggressive groups. These scales may be used to develop a greater understanding of group and environmental characteristics that lead to defensive in-group positivity.

The master’s thesis outlines the problem of authentication. It describes authentication factors like ownership, knowledge and inherent. There are described properties of each of that. Authentication based on ownership focuses on authenticators - the smartcards. The thesis also describes different types of smartcards (contact, contactless and hybrid smartcards) and refers to their basic properties. Emphasis is placed on the description of contact and contactless smartcard, specifically focusing on .NET smartcards. It describes their internal components such as memory (RAM, ROM, EEPROM), crypto processor etc. Smartcards are also examined in terms of support for cryptographic primitives. The thesis also introduces the cryptographic methods and principles describing symmetric and asymmetric ciphers. Symmetric ciphers are divided in to stream and block ciphers. There is description of asymmetric cipher, digital signature etc. This work also touches on the fundamental principles required for safe programming. Part of this work is also practical implementation (programs). Practical part aims to implement the communication between the user and AC (Access Control) AASR system. The first suite of applications provides encrypted communication between the PC and smartcards. These applications should create on smartcard services that will be able to perform operations on the client side, which are necessary to authenticate in the AASR system. The paper also presents algorithms for working with big numbers - addition, subtraction, multiplication, and Montgomery's algorithm for multiplication. The second application implements the functionality of AC components (Access Control). This functionality is for example – authenticate received token, digital signature authentication, generating random numbers, logging etc.

The thesis deals with security of the Android operating system, both general security features and options for storing sensitive data. The suitability of Android KeyStore for storing sensitive data and the possibility of using the secure element for safe application calculations and smart card emulation are discussed. Using Host-based Card Emulation for contactless smart card emulation is discussed. The performance analysis of modular arithmetic operations for numbers with high bit length is examined. Following these analysis, an implementation of application for software contactless smart card emulation of HM12 and HM14 cryptographic protocol is proposed. And an implementation of application for verifying smart cards with these protocols is proposed. Also scheme for secure storage of sensitive data is proposed.

The thesis has been involved in the receivables management in a selected business corporation, namely management of trade account receivables. Measures, the application of which should improve the situation in the selected company, are proposed with regard to the development and status of receivables at the reporting period.

This Diploma thesis solves a quick coupler design for a loader. In introduction of the Diploma thesis are mentioned two potential designes and convenient solutions. Subsequently are outlined two practicable designes of a quick coupler for a original bucket, as a data componant of the second construction design is enclosed basic strength calculation. The ending point of the thesis deals and compare with the force decrease in use of a quick coupler and appraisals achieved ascertainment.

Die Sicherheit und Zuverlässigkeit von Anwendungen, welche schutzwürdige Daten verarbeiten, lässt sich durch die geschützte Verlagerung in die Cloud mit einer Kombination aus zielgrößenabhängiger Datenkodierung, kontinuierlicher mehrfacher Dienstauswahl, dienstabhängiger optimierter Datenverteilung und kodierungsabhängiger Algorithmen deutlich erhöhen und anwenderseitig kontrollieren. Die Kombination der Verfahren zu einer anwendungsintegrierten Stealth-Schutzschicht ist eine notwendige Grundlage für die Konstruktion sicherer Anwendungen mit zusicherbaren Sicherheitseigenschaften im Rahmen eines darauf angepassten Softwareentwicklungsprozesses.:1 Problemdarstellung 1.1 Einführung 1.2 Grundlegende Betrachtungen 1.3 Problemdefinition 1.4 Einordnung und Abgrenzung 2 Vorgehensweise und Problemlösungsmethodik 2.1 Annahmen und Beiträge 2.2 Wissenschaftliche Methoden 2.3 Struktur der Arbeit 3 Stealth-Kodierung für die abgesicherte Datennutzung 3.1 Datenkodierung 3.2 Datenverteilung 3.3 Semantische Verknüpfung verteilter kodierter Daten 3.4 Verarbeitung verteilter kodierter Daten 3.5 Zusammenfassung der Beiträge 4 Stealth-Konzepte für zuverlässige Dienste und Anwendungen 4.1 Überblick über Plattformkonzepte und -dienste 4.2 Netzwerkmultiplexerschnittstelle 4.3 Dateispeicherschnittstelle 4.4 Datenbankschnittstelle 4.5 Stromspeicherdienstschnittstelle 4.6 Ereignisverarbeitungsschnittstelle 4.7 Dienstintegration 4.8 Entwicklung von Anwendungen 4.9 Plattformäquivalente Cloud-Integration sicherer Dienste und Anwendungen 4.10 Zusammenfassung der Beiträge 5 Szenarien und Anwendungsfelder 5.1 Online-Speicherung von Dateien mit Suchfunktion 5.2 Persönliche Datenanalyse 5.3 Mehrwertdienste für das Internet der Dinge 6 Validierung 6.1 Infrastruktur für Experimente 6.2 Experimentelle Validierung der Datenkodierung 6.3 Experimentelle Validierung der Datenverteilung 6.4 Experimentelle Validierung der Datenverarbeitung 6.5 Funktionstüchtigkeit und Eigenschaften der Speicherdienstanbindung 6.6 Funktionstüchtigkeit und Eigenschaften der Speicherdienstintegration 6.7 Funktionstüchtigkeit und Eigenschaften der Datenverwaltung 6.8 Funktionstüchtigkeit und Eigenschaften der Datenstromverarbeitung 6.9 Integriertes Szenario: Online-Speicherung von Dateien 6.10 Integriertes Szenario: Persönliche Datenanalyse 6.11 Integriertes Szenario: Mobile Anwendungen für das Internet der Dinge 7 Zusammenfassung 7.1 Zusammenfassung der Beiträge 7.2 Kritische Diskussion und Bewertung 7.3 Ausblick Verzeichnisse Tabellenverzeichnis Abbildungsverzeichnis Listings Literaturverzeichnis Symbole und Notationen Software-Beiträge für native Cloud-Anwendungen Repositorien mit Experimentdaten / The security and reliability of applications processing sensitive data can be significantly increased and controlled by the user by a combination of techniques. These encompass a targeted data coding, continuous multiple service selection, service-specific optimal data distribution and coding-specific algorithms. The combination of the techniques towards an application-integrated stealth protection layer is a necessary precondition for the construction of safe applications with guaranteeable safety properties in the context of a custom software development process.:1 Problemdarstellung 1.1 Einführung 1.2 Grundlegende Betrachtungen 1.3 Problemdefinition 1.4 Einordnung und Abgrenzung 2 Vorgehensweise und Problemlösungsmethodik 2.1 Annahmen und Beiträge 2.2 Wissenschaftliche Methoden 2.3 Struktur der Arbeit 3 Stealth-Kodierung für die abgesicherte Datennutzung 3.1 Datenkodierung 3.2 Datenverteilung 3.3 Semantische Verknüpfung verteilter kodierter Daten 3.4 Verarbeitung verteilter kodierter Daten 3.5 Zusammenfassung der Beiträge 4 Stealth-Konzepte für zuverlässige Dienste und Anwendungen 4.1 Überblick über Plattformkonzepte und -dienste 4.2 Netzwerkmultiplexerschnittstelle 4.3 Dateispeicherschnittstelle 4.4 Datenbankschnittstelle 4.5 Stromspeicherdienstschnittstelle 4.6 Ereignisverarbeitungsschnittstelle 4.7 Dienstintegration 4.8 Entwicklung von Anwendungen 4.9 Plattformäquivalente Cloud-Integration sicherer Dienste und Anwendungen 4.10 Zusammenfassung der Beiträge 5 Szenarien und Anwendungsfelder 5.1 Online-Speicherung von Dateien mit Suchfunktion 5.2 Persönliche Datenanalyse 5.3 Mehrwertdienste für das Internet der Dinge 6 Validierung 6.1 Infrastruktur für Experimente 6.2 Experimentelle Validierung der Datenkodierung 6.3 Experimentelle Validierung der Datenverteilung 6.4 Experimentelle Validierung der Datenverarbeitung 6.5 Funktionstüchtigkeit und Eigenschaften der Speicherdienstanbindung 6.6 Funktionstüchtigkeit und Eigenschaften der Speicherdienstintegration 6.7 Funktionstüchtigkeit und Eigenschaften der Datenverwaltung 6.8 Funktionstüchtigkeit und Eigenschaften der Datenstromverarbeitung 6.9 Integriertes Szenario: Online-Speicherung von Dateien 6.10 Integriertes Szenario: Persönliche Datenanalyse 6.11 Integriertes Szenario: Mobile Anwendungen für das Internet der Dinge 7 Zusammenfassung 7.1 Zusammenfassung der Beiträge 7.2 Kritische Diskussion und Bewertung 7.3 Ausblick Verzeichnisse Tabellenverzeichnis Abbildungsverzeichnis Listings Literaturverzeichnis Symbole und Notationen Software-Beiträge für native Cloud-Anwendungen Repositorien mit Experimentdaten