基於通行碼之認證金鑰交換協定(Password-based Authenticated Key Exchange)為一項使要進行交換訊息之雙方做相互驗證並產生一把共享金鑰的技術。藉由通訊雙方共享一組通行碼做為身份驗證的依據，並且在驗證結束後產生一把僅有雙方才知道的祕密通訊金鑰，往後進行傳遞機密資訊時即可透過此金鑰建立安全的通訊管道。 本篇論文提出一個在主從式架構(Client/Server model)下基於晶格(lattice)之通行碼認證金鑰交換協定，用戶端只需記錄與伺服器共享之通行碼，而伺服器端除了通行碼外擁有屬於自己的公私鑰對，雙方間透過共享之通行碼進行相互驗證，並且在兩個步驟內完成認證及金鑰交換。在安全性上基於晶格密碼系統之難問題，若未來量子電腦問世能夠抵擋其強大運算能力之攻擊，達到安全且有效率之通行碼認證金鑰協議。 / The password-based authenticated key exchange is a technology that allows both parties to perform mutual authentication and generate a shared session key. They through the shared password as the basis for authentication and generate a session key that is only known by both parties. At last, they can use this key to establish a secure channel to transmit secret message. We propose a password-based authenticated key exchange from lattices for Client-Server model. The client only need to remember the password rather than the private key, and the server except keep the password and its own public/private key pair. Both parties execute the mutual authentication via the shared password and accomplish the key exchange within two steps. The security of our protocol is based on LWE problem for lattices, so it is secure even an attacker uses a quantum computer.

This master's project deals with location based systems and their application in information distribution. The work discuss kinds of getting actual location. Then it focuses on problems of developing applications and description of Microsoft technologies for mobile devices. Based on obtained theoretical information we present design, implementation and testing of our own location based system.

Made available in DSpace on 2016-04-04T18:31:36Z (GMT). No. of bitstreams: 1 Vitor Chaves de Oliveira.pdf: 1928054 bytes, checksum: 49bf6198a68438069d6ef8b9a2ec77e9 (MD5) Previous issue date: 2012-12-10 / In recent years, virtualization computing has become a worldwide reality present in datacenters servers of most organizations. The motivations for the use of this solution are focused primarily on cost reduction and increases in availability, integrity and security of data. Based on these benefits, recently it was started the use of this technology for personal computers as well. That is, for desktops, giving birth to the so-called desktop virtualization. Given the technical advantages of the approach, its growth has been so significant that, before 2014, it is expected to be present in over 90% of organizations. However, this new method is completely based on a physical client-server architecture, which increases the importance of the communication network that makes this technique possible. Therefore, analyzing the network in order to investigate the effects according to the environment implemented, becomes crucial. In this work it s varied the local s client hardware and the application, i.e. the service used. The purpose was to detail their effects on computer networks in a Quality of Service (QoS) parameter, throughput. Secondarily are outlined perceptions regarding the Quality of Experience (QoE). / Nos ?ltimos anos, a virtualiza??o computacional se tornou uma realidade nos servidores presentes nos data-centers da maioria das organiza??es no mundo. As motiva??es para o emprego desta solu??o est?o centradas, primordialmente, na redu??o de custos e em aumentos na disponibilidade, na integridade e na seguran?a dos dados. Com base nestes benef?cios, recentemente, se come?ou a aproveitar esta tecnologia tamb?m para os computadores pessoais. Isto ?, para os desktops, dando origem a chamada virtualiza??o de desktop. Dadas as vantagen t?cnicas da abordagem, seu crescimento tem sido t?o expressivo que, antes de 2014, se espera que ela esteja presente em mais de 90% das organiza??es. Todavia, este m?todo ? totalmente baseado em uma arquitetura cliente-servidor f?sica, o que aumenta a import?ncia da rede de comunica??o que torna a t?cnica poss?vel. Logo, analisar a rede, a fim de investigar os impactos de acordo com o ambiente implementado, se torna fundamental. Neste trabalho variamos o hardware local do cliente e a aplica??o, isto ?, o servi?o utilizado. A finalidade foi a de detalhar seus efeitos, em redes de computadores, em um par?metro de Qualidade de Servi?o (QoS), a vaz?o. Secundariamente s?o esbo?adas percep??es de Qualidade da Experi?ncia (QoE).

Thesis (doctoral) - Humboldt Universität, Berlin, 2003. / Includes bibliographical references (p. [107]-113) and index. Also issued online.

L'objectif de cette thèse est l'étude d'un environnement d'exécution pour machines parallèles sans mémoire commune. Elle comprend la définition d'un modèle de programme parallèle, basé sur l'échange de message offrant une forme restreinte de mémoire partagée. La communication est indirecte, via des portes; les processus utilisent les barrières pour la synchronisation. Les entités du système. processus, portes et barrières, sont créées dynamiquement, et placées sur un processeur quelconque du réseau de processeurs de façon explicite. Nous proposons une implantation de ce modèle comme la mise en oeuvre systématique d'une architecture client/serveur. Cette implantation a été efféctuée sur une machine Supemode. La base est un Micro Noyau Parallèle, où le composant principal est un mécanisme d'appel de procédure à distance minimal. / This thesis describes an execution environment for parallel machines without shared memory. A parallel programming model based on message passing, with a special shared memory. In this model, process communication occurs indirectly, via ports, and the processes use barriers for synchronization. All the entities of the system, such as processes, ports and barriers, are created dynamically and loaded on any processor of the network of processors. The implementation architecture of our model is a systematic realization of the client/server model. An implementation is proposed in a Supernode parallel machine as a parallel micro kernel. The principal parallel micro kernel component is a minimal remote procedure call mechanism.

L'objectif de cette thèse est l'étude d'un environnement d'exécution pour machines parallèles sans mémoire commune. Elle comprend la définition d'un modèle de programme parallèle, basé sur l'échange de message offrant une forme restreinte de mémoire partagée. La communication est indirecte, via des portes; les processus utilisent les barrières pour la synchronisation. Les entités du système. processus, portes et barrières, sont créées dynamiquement, et placées sur un processeur quelconque du réseau de processeurs de façon explicite. Nous proposons une implantation de ce modèle comme la mise en oeuvre systématique d'une architecture client/serveur. Cette implantation a été efféctuée sur une machine Supemode. La base est un Micro Noyau Parallèle, où le composant principal est un mécanisme d'appel de procédure à distance minimal. / This thesis describes an execution environment for parallel machines without shared memory. A parallel programming model based on message passing, with a special shared memory. In this model, process communication occurs indirectly, via ports, and the processes use barriers for synchronization. All the entities of the system, such as processes, ports and barriers, are created dynamically and loaded on any processor of the network of processors. The implementation architecture of our model is a systematic realization of the client/server model. An implementation is proposed in a Supernode parallel machine as a parallel micro kernel. The principal parallel micro kernel component is a minimal remote procedure call mechanism.

L'objectif de cette thèse est l'étude d'un environnement d'exécution pour machines parallèles sans mémoire commune. Elle comprend la définition d'un modèle de programme parallèle, basé sur l'échange de message offrant une forme restreinte de mémoire partagée. La communication est indirecte, via des portes; les processus utilisent les barrières pour la synchronisation. Les entités du système. processus, portes et barrières, sont créées dynamiquement, et placées sur un processeur quelconque du réseau de processeurs de façon explicite. Nous proposons une implantation de ce modèle comme la mise en oeuvre systématique d'une architecture client/serveur. Cette implantation a été efféctuée sur une machine Supemode. La base est un Micro Noyau Parallèle, où le composant principal est un mécanisme d'appel de procédure à distance minimal. / This thesis describes an execution environment for parallel machines without shared memory. A parallel programming model based on message passing, with a special shared memory. In this model, process communication occurs indirectly, via ports, and the processes use barriers for synchronization. All the entities of the system, such as processes, ports and barriers, are created dynamically and loaded on any processor of the network of processors. The implementation architecture of our model is a systematic realization of the client/server model. An implementation is proposed in a Supernode parallel machine as a parallel micro kernel. The principal parallel micro kernel component is a minimal remote procedure call mechanism.

This thesis describes a development of a modern client-server application for text recognition on iOS platform. The reader is acquainted with common principles of a client-server model, including its known architecture styles, and with a distribution of logical layers between both sides of the model. After that the thesis depicts current trends and examples of suitable technologies for creating an application programming interface of a web server. Possible ways of text recognition on the server side are discussed as well. In context of a client side, the thesis provides an insight into iOS platform and a few important concepts in iOS application development. Following implementation of the server side is stressed to be reusable as much as possible for different kinds of use cases. Last but not least, the thesis provides a simple iOS framework for a direct communication with the recognition server. Finally, an application for evaluation of food ingredients from a packaging material is implemented as an example of usage.

This thesis describes a process of creating a mobile application using deep convolutional neural networks. The process starts with proposal of the main idea, followed by product and technical design, implementation and evaluation. The thesis also explores the technical background of image recognition, and chooses the most suitable options for the purpose of the application. These are object detection and multi-label classification, which are both implemented, evaluated and compared. The resulting application tries to bring value from both user and technical point of view.

The main goal of this work is creating client-server application with image processing and cryptographic verification of image source and creation time. The work focuses on creating a mobile client application on the Android platform that securly takes photos by mobile device camera, processes captured images and provides a digital signature, timestamp and GPS location. The main part of the work is secure key exchange, encrypted communication, data and energy efficiency of the client-server application. The server application is implemented on the Java EE platform and processes the received image, performs object detection, object recognition in the image and provides a timestamp from a trusted server. Then taken photo can be considered as a trusted electronic document usable as valid evidence for the judical or administrative proceedings.