Página 1 dos resultados de 278 itens digitais encontrados em 0.014 segundos

Autenticação contínua de usuários em redes de computadores.; Users continuous authentication in computers networks.

Brosso, Maria Ines Lopes
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 05/05/2006 PT
Relevância na Pesquisa
46.32%
A Computação Ciente de Contexto permite a obtenção e utilização de informações de contexto adquiridas de dispositivos computacionais no ambiente, com o objetivo de prover serviços; esta dinâmica aliada à evolução das redes de computadores vem provocando profundas modificações nos aspectos sociais e comportamentais das pessoas, uma vez que gradativamente têm necessidade de viverem imersas na tecnologia e integradas ao ambiente, com transparência e mobilidade, e de tal forma que as aplicações de software se adaptam ao comportamento das pessoas e nas informações de contexto capturadas do ambiente. Um dos desafios desta interação ser humano - ambiente - tecnologia - ubiqüidade é garantir a segurança. Como principal inovação e contribuição, esta tese propõe um mecanismo de autenticação contínua de usuários que faz uso de informações de contexto do ambiente, da análise do comportamento do usuário, da biometria facial, das teorias comportamentais de Skinner e da Confiança Matemática da Teoria das Evidências de Dempster-Shafer, para compor uma política de segurança adaptativa e um Sistema de Autenticação Contínua de Usuários Conhecidos - KUCAS (Known User Continuous Authentication System), que estabelece níveis de confiança para autenticar o usuário através da análise do comportamento dele em um ambiente ou domínio específico nas redes de computadores...

Password secured sites : stepping forward with keystroke dynamics

Magalhães, Paulo Sérgio; Revett, Kenneth; Santos, Henrique Dinis dos
Fonte: IEEE Computer Society Publicador: IEEE Computer Society
Tipo: Conferência ou Objeto de Conferência
Publicado em //2005 ENG
Relevância na Pesquisa
36.24%
Computer Authentication is a critical component of most computer systems, especially those used in e-Commerce activities over the internet. Global access to information makes security, namely the authentication process, a critical design issue in these systems. In what concerns to authentication, what is required is a reliable, hardware independent and efficient security system. In this paper, we propose an extension to a keystroke dynamics based security system. We provide evidence that completely software based systems can be as effective as expensive and cumbersome hardware based systems. Our system is a behavioral based system that captures the normal typing patterns of a user and uses that information, in addition to standard login/password security to provide a system that is user-friendly and very effective at detecting imposters. The results provide a means of dealing with enhanced security that is growing in demand in web-based applications based on Commerce.

Critical aspects In authentication graphic keys

Magalhães, Paulo Sérgio; Revett, Kenneth; Santos, Henrique Dinis dos
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2006 ENG
Relevância na Pesquisa
46.24%
In order to increase the number of possible keys (key’s space), some applications are using, as the user’s authentication secret, images instead of words, taking advantage of the several possibilities for each mouse click and of the fact that humans memorize images better then words. This paper presents the characterisation of the graphical keys chosen by almost 200 regular users of a website and the results show some important fact that must taken into account to maximize the security of the authentication process.

Dinâmica gestual com condutividade da pele : uma abordagem multimodal para autenticação biométrica; Gestural dynamics with skin conductivity : a multimodal approach to biometric authentication

Sá,Vítor J.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Tese de Doutorado
Publicado em 15/04/2014 POR
Relevância na Pesquisa
36.51%
Tese de doutoramento do Programa Doutoral em Tecnologias e Sistemas de Informação; Esta tese consiste num estudo de viabilidade (social e tecnológica) de uma solução de autenticação com recurso à biometria comportamental de dinâmica gestual (restringida ao gesto de apontar) e à biometria cognitiva de condutividade da pele. O problema da transmissibilidade do segredo de autenticação, seja por algo que se sabe ou por algo que se possui, tem-nos conduzido à utilização de tecnologias biométricas, em que o segredo consiste em algo que se é ou algo que se faz. No entanto, as biometrias podem sofrer do problema da replicabilidade, mesmo quando se trata de biometrias comporta mentais, o que nos leva às biometrias cognitivas. Para além disso, no controlo de acesso lógico coloca-se o problema da validade da autenticação ao longo do tempo. Este problema, por vezes denominado problema de autenticação contínua, é mais facilmente ultrapassado com recurso a sistemas multimodais, uma vez que diferentes processos de autenticação, em conjunto, podem responder de um modo mais eficiente a diferentes momentos de autenticação. A multimodalidade é ainda uma forma conveniente de dificultar a transmissibilidade/replicabilidade dos padrões biométricos. A biometria cognitiva menos intrusiva é a condutividade da pele existindo estudos recentes que parecem indicar a existência de margem e potencial para reduzir as taxas de erro que ainda lhe estão associadas. Por outro lado...

Quantitative analysis of PIN choices: a contribution to the establishment of authentication requirements

Carvalho, José Carlos; Magalhães, Maria José; Sá, Vítor; Tenreiro de Magalhães, Sérgio
Fonte: Academic Conferences and Publishing International Limited Publicador: Academic Conferences and Publishing International Limited
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2015 ENG
Relevância na Pesquisa
36.24%
The authentication using a PIN number remains one of the most used ways to enter a system (mobile phone, ATM, etc.). Many people seem to dislike this form of authentication because they simply despise their use, placing unsafe PINs just because they have to put some. Some relevant results are the combination 1234, thecombinations using only one digit (example: 1111), or the central line of the numerical keypad. On the other hand there is some understanding because it is proven that remember strong passwords is a difficult task for humans, and the tendency is to choose the simplest ones. This research had a sample of 497 participants and aimed to understand the preferred choice of the participants in relation to the number of digits used for a PIN number (a choice between four and/or six digits) and realized the amount of times that each of the available digits was used. To this end it was developed a web-based tool for entering the data. This application was intended only to the data collection process, being the information processed further. Through this application, the user was asked to enter four and/or six-digit PINs. The method does not raise any doubt on the participants, which were informed about the anonymity and confidentiality of the data...

Single sign-on na FCUL

Estanqueiro, Francisco Wallenstein Teixeira
Fonte: Universidade de Lisboa Publicador: Universidade de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2010 POR
Relevância na Pesquisa
36.41%
Trabalho de projecto de mestrado em Engenharia Informática, apresentado à Universidade de Lisboa, através da Faculdade de Ciências, 2010; Este projecto insere-se no âmbito da cadeira de Projecto em Engenharia Informática (PEI) do Mestrado de Engenharia Informática da Faculdade de Ciências da Universidade de Lisboa (FCUL). Este trabalho teve como principal objectivo a criação de um sistema de Single Sign-On (SSO) para as aplicações web disponibilizadas pelo Centro de Informática (CI) da FCUL. Single Sign-On (SSO) é um processo de autenticação em sessão, que permite a um utilizador introduzir as suas credenciais de acesso apenas uma vez para aceder a múltiplas aplicações protegidas. O processo autentica o utilizador para todas as aplicações a que este tem direito de acesso e elimina a necessidade de se autenticar novamente ao mudar de aplicação durante a sessão. Deste modo, toda a autenticação passará a ser feita de um modo centralizado, ficando o serviço de SSO com a responsabilidade de fornecer informação confiável de identidade dos utilizadores às aplicações. De forma a atingir os objectivos propostos, foi necessário estudar com detalhe o estado da arte, assim como as possíveis soluções para a implementação de um sistema deste género...

The brushstroke and materials of Amadeo de Souza-Cardoso combined in an authentication tool

Montagner, Cristina
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Tese de Doutorado
Publicado em /02/2015 ENG
Relevância na Pesquisa
36.24%
Nowadays, authentication studies for paintings require a multidisciplinary approach, based on the contribution of visual features analysis but also on characterizations of materials and techniques. Moreover, it is important that the assessment of the authorship of a painting is supported by technical studies of a selected number of original artworks that cover the entire career of an artist. This dissertation is concerned about the work of modernist painter Amadeo de Souza-Cardoso. It is divided in three parts. In the first part, we propose a tool based on image processing that combines information obtained by brushstroke and materials analysis. The resulting tool provides qualitative and quantitative evaluation of the authorship of the paintings; the quantitative element is particularly relevant, as it could be crucial in solving authorship controversies, such as judicial disputes. The brushstroke analysis was performed by combining two algorithms for feature detection, namely Gabor filter and Scale Invariant Feature Transform. Thanks to this combination (and to the use of the Bag-of-Features model), the proposed method shows an accuracy higher than 90% in distinguishing between images of Amadeo’s paintings and images of artworks by other contemporary artists. For the molecular analysis...

A User Authentication Scheme Using Physiological and Behavioral Biometrics for Multitouch Devices

Koong, Chorng-Shiuh; Yang, Tzu-I; Tseng, Chien-Chao
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.24%
With the rapid growth of mobile network, tablets and smart phones have become sorts of keys to access personal secured services in our daily life. People use these devices to manage personal finances, shop on the Internet, and even pay at vending machines. Besides, it also helps us get connected with friends and business partners through social network applications, which were widely used as personal identifications in both real and virtual societies. However, these devices use inherently weak authentication mechanism, based upon passwords and PINs that is not changed all the time. Although forcing users to change password periodically can enhance the security level, it may also be considered annoyances for users. Biometric technologies are straightforward because of the simple authentication process. However, most of the traditional biometrics methodologies require diverse equipment to acquire biometric information, which may be expensive and not portable. This paper proposes a multibiometric user authentication scheme with both physiological and behavioral biometrics. Only simple rotations with fingers on multitouch devices are required to enhance the security level without annoyances for users. In addition, the user credential is replaceable to prevent from the privacy leakage.

Quantitative analysis of PIN choices: a contribution to the establishment of authentication requirements

Carvalho, José Carlos; Magalhães, Maria José; Sá, Vítor J.; Magalhães, Paulo Sérgio Tenreiro
Fonte: Academic Conferences and Publishing International Limited Publicador: Academic Conferences and Publishing International Limited
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2015 ENG
Relevância na Pesquisa
36.24%
The authentication using a PIN number remains one of the most used ways to enter a system (mobile phone, ATM, etc.). Many people seem to dislike this form of authentication because they simply despise their use, placing unsafe PINs just because they have to put some. Some relevant results are the combination 1234, the combinations using only one digit (example: 1111), or the central line of the numerical keypad. On the other hand there is some understanding because it is proven that remember strong passwords is a difficult task for humans, and the tendency is to choose the simplest ones. This research had a sample of 497 participants and aimed to understand the preferred choice of the participants in relation to the number of digits used for a PIN number (a choice between four and/or six digits) and realized the amount of times that each of the available digits was used. To this end it was developed a web-based tool for entering the data. This application was intended only to the data collection process, being the information processed further. Through this application, the user was asked to enter four and/or six-digit PINs. The method does not raise any doubt on the participants, which were informed about the anonymity and confidentiality of the data...

Using Medical History Embedded in Biometrics Medical Card for User Identity Authentication: Data Representation by AVT Hierarchical Data Tree

Fong, Simon; Zhuang, Yan
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.32%
User authentication has been widely used by biometric applications that work on unique bodily features, such as fingerprints, retina scan, and palm vessels recognition. This paper proposes a novel concept of biometric authentication by exploiting a user's medical history. Although medical history may not be absolutely unique to every individual person, the chances of having two persons who share an exactly identical trail of medical and prognosis history are slim. Therefore, in addition to common biometric identification methods, medical history can be used as ingredients for generating Q&A challenges upon user authentication. This concept is motivated by a recent advancement on smart-card technology that future identity cards are able to carry patents' medical history like a mobile database. Privacy, however, may be a concern when medical history is used for authentication. Therefore in this paper, a new method is proposed for abstracting the medical data by using attribute value taxonomies, into a hierarchical data tree (h-Data). Questions can be abstracted to various level of resolution (hence sensitivity of private data) for use in the authentication process. The method is described and a case study is given in this paper.

Optimal information in authentication of food and beverages

Quintana, Fernando A.; Gutiérrez Inostroza, Luis Alberto
Fonte: SAGE Publications Publicador: SAGE Publications
Tipo: Artículo de revista
EN
Relevância na Pesquisa
36.32%
Artículo de publicación ISI; Food and beverage authentication is the process by which food or beverages are verified as complying with their label descriptions (Winterhalter, 2007). A common way to deal with an authentication process is to measure attributes, such as, groups of chemical compounds on samples of food, and then use these as input for a classification method. In many applications there may be several types of measurable attributes. An important problem thus consists of determining which of these would provide the best information, in the sense of achieving the highest possible classification accuracy at low cost. We approach the problem under a decision theoretic strategy, by framing it as the selection of an optimal test (Geisser and Johnson, 1992) or as the optimal dichotomization of screening tests variables (Wang and Geisser, 2005), where the ‘test’ is defined through a classification model applied to different groups of chemical compounds. The proposed methodology is motivated by data consisting of measurements of 19 chemical compounds (Anthocyanins, Organic Acids and Flavonols) on samples of Chilean red wines. The main goal is to determine the combination of chemical compounds that provides the best information for authentication of wine varieties...

An Asymptotically Optimal RFID Authentication Protocol Against Relay Attacks

Avoine, Gildas; Tchamkerten, Aslan
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/09/2008
Relevância na Pesquisa
36.24%
Relay attacks are a major concern for RFID systems: during an authentication process an adversary transparently relays messages between a verifier and a remote legitimate prover. We present an authentication protocol suited for RFID systems. Our solution is the first that prevents relay attacks without degrading the authentication security level: it minimizes the probability that the verifier accepts a fake proof of identity, whether or not a relay attack occurs.; Comment: 10 pages

A Comparative Usability Study of Two-Factor Authentication

De Cristofaro, Emiliano; Du, Honglu; Freudiger, Julien; Norcie, Greg
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.29%
Two-factor authentication (2F) aims to enhance resilience of password-based authentication by requiring users to provide an additional authentication factor, e.g., a code generated by a security token. However, it also introduces non-negligible costs for service providers and requires users to carry out additional actions during the authentication process. In this paper, we present an exploratory comparative study of the usability of 2F technologies. First, we conduct a pre-study interview to identify popular technologies as well as contexts and motivations in which they are used. We then present the results of a quantitative study based on a survey completed by 219 Mechanical Turk users, aiming to measure the usability of three popular 2F solutions: codes generated by security tokens, one-time PINs received via email or SMS, and dedicated smartphone apps (e.g., Google Authenticator). We record contexts and motivations, and study their impact on perceived usability. We find that 2F technologies are overall perceived as usable, regardless of motivation and/or context of use. We also present an exploratory factor analysis, highlighting that three metrics -- ease-of-use, required cognitive efforts, and trustworthiness -- are enough to capture key factors affecting 2F usability.; Comment: A preliminary version of this paper appears in USEC 2014

Towards Public Key Infrastructure less authentication in Session Initiation Protocol

Hasib, Abdullah Al; Azfar, Abdullah; Morshed, Md. Sarwar
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/02/2010
Relevância na Pesquisa
36.29%
The Session Initiation Protocol (SIP) has become the most predominant protocol for Voice over Internet Protocol (VoIP) signaling. Security of SIP is an important consideration for VoIP communication as the traffic is transmitted over the insecure IP network. And the authentication process in SIP ranges from pre-shared secret based solutions to Public Key Infrastructure (PKI) based solution. However, due to the limitations in PKI based solutions, some PKI less authentications mechanisms are proposed. This paper aims to present an overview of different authentication methods used in or together with SIP. We start by highlighting the security issues in SIP in the context of VoIP communication. Then we illustrate the current activities regarding the SIP authentication mechanisms including the recent developments in the research community and standardization efforts within the Internet Engineering Task Force (IETF). Finally we analyze the security aspects of these approaches.; Comment: International Journal of Computer Science Issues, IJCSI, Vol. 7, Issue 1, No. 2, January 2010, http://ijcsi.org/articles/Towards-Public-Key-Infrastructure-less-authentication-in-Session-Initiation-Protocol.php

A Physical-Layer Authentication Assisted Scheme for Enhancing 3GPP Authentication

Wu, Xiaofu; Yan, Zhen; Ling, Cong; Xia, Xiang-Gen
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/02/2015
Relevância na Pesquisa
36.45%
The broadcast nature of radio propagation makes wireless networks vulnerable to eavesdropping attacks. To enhance authentication strength in wireless networks, various physical layer authentication schemes were proposed by exploiting physical layer characteristics. Recently, we proposed a novel PHYsical layer Phase Challenge-Response Authentication Scheme (PHY PCRAS), which exploits both the reciprocity and randomness of the phase responses over independent parallel multicarrier channels. In this paper, we first extend it to more practical Orthogonal Frequency-Division Multiplexing (OFDM) transmission. Then, security analysis is provided, and information-theoretic security is formulated for PHY-PCRAS over both independent and correlated subchannels. Finally, we propose a practical framework for incorporating the mechanism of physical layer authentication into the current Third Generation Partnership Project (3GPP) Authentication and Key Agreement (AKA) protocol. Compared to the conventional 3GPP AKA protocol, the PHY-PCRAS assisted authentication process can ensure some degree of information-theoretic security. It is also possible to further protect the subsequent classic AKA process on the air through the physical layer secure information transmission technique.; Comment: 12 pages...

Multivariate Bayesian semiparametric models for authentication of food and beverages

Gutiérrez, Luis; Quintana, Fernando A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 27/02/2012
Relevância na Pesquisa
36.32%
Food and beverage authentication is the process by which foods or beverages are verified as complying with its label description, for example, verifying if the denomination of origin of an olive oil bottle is correct or if the variety of a certain bottle of wine matches its label description. The common way to deal with an authentication process is to measure a number of attributes on samples of food and then use these as input for a classification problem. Our motivation stems from data consisting of measurements of nine chemical compounds denominated Anthocyanins, obtained from samples of Chilean red wines of grape varieties Cabernet Sauvignon, Merlot and Carm\'{e}n\`{e}re. We consider a model-based approach to authentication through a semiparametric multivariate hierarchical linear mixed model for the mean responses, and covariance matrices that are specific to the classification categories. Specifically, we propose a model of the ANOVA-DDP type, which takes advantage of the fact that the available covariates are discrete in nature. The results suggest that the model performs well compared to other parametric alternatives. This is also corroborated by application to simulated data.; Comment: Published in at http://dx.doi.org/10.1214/11-AOAS492 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org)

Authentication Schemes Using Polynomials Over Non-Commutative Rings

Valluri, Maheswara Rao
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/01/2013
Relevância na Pesquisa
36.41%
Authentication is a process by which an entity,which could be a person or intended computer,establishes its identity to another entity.In private and public computer networks including the Internet,authentication is commonly done through the use of logon passwords. Knowledge of the password is assumed to guarantee that the user is authentic.Internet business and many other transactions require a more stringent authentication process. The aim of this paper is to propose two authentication schemes based on general non-commutative rings. The key idea of the schemes is that for a given non-commutative ring; one can build polynomials on additive structure and takes them as underlying work structure. By doing so, one can implement authentication schemes, one of them being zero-knowledge interactive proofs of knowledge, on multiplicative structure of the ring. The security of the schemes is based on the intractability of the polynomial symmetrical decomposition problem over the given non-commutative ring.; Comment: International Journal on Cryptography and Information Security (IJCIS),Vol.2, No.4, December 2012

An Improved Timestamp-Based Password Authentication Scheme Using Smart Cards

Pathan, Al-Sakib Khan; Hong, Choong Seon
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/12/2007
Relevância na Pesquisa
36.32%
With the recent proliferation of distributed systems and networking, remote authentication has become a crucial task in many networking applications. Various schemes have been proposed so far for the two-party remote authentication; however, some of them have been proved to be insecure. In this paper, we propose an efficient timestamp-based password authentication scheme using smart cards. We show various types of forgery attacks against a previously proposed timestamp-based password authentication scheme and improve that scheme to ensure robust security for the remote authentication process, keeping all the advantages that were present in that scheme. Our scheme successfully defends the attacks that could be launched against other related previous schemes. We present a detailed cryptanalysis of previously proposed Shen et. al scheme and an analysis of the improved scheme to show its improvements and efficiency.; Comment: 6 pages

Quantum direct communication with mutual authentication

Yen, Cheng-An; Horng, Shi-Jinn; Goan, Hsi-Sheng; Kao, Tzong-Wann; Chou, Yao-Hsin
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 19/03/2009
Relevância na Pesquisa
36.43%
In this paper, we first point out that some recently proposed quantum direct communication (QDC) protocols with authentication are vulnerable under some specific attacks, and the secrete message will leak out to the authenticator who is introduced to authenticate users participating in the communication. We then propose a new protocol that is capable of achieving secure QDC with authentication as long as the authenticator would do the authentication job faithfully. Our quantum protocol introduces a mutual authentication procedure, uses the quantum Bell states, and applies unitary transformations in the authentication process. Then it exploits and utilizes the entanglement swapping and local unitary operations in the communication processes. Thus, after the authentication process, the client users are left alone to communicate with each other, and the authenticator has no access to the secrete message. In addition, our protocol does not require a direct quantum link between any two users, who want to communicate with each other. This may also be an appealing advantage in the implementation of a practical quantum communication network.

Group key agreement protocols with implicit key authentication

Kim, Jisoo
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Masters Project Formato: 397129 bytes; 165393 bytes; application/pdf; application/pdf
EN_US
Relevância na Pesquisa
36.41%
There have been numerous studies performed on secure group communication over unsecured channels such as the Internet and ad-hoc network. Most of the results are focused on cryptographic methods to share secret keys within the group. In the real world, however, we cannot establish an application for group communication without considering authentication of each peer (group member) since the adversary could digitally disguise itself and intrude into the key sharing process without valid membership. Therefore, authentication is an inevitable component for any secure communication protocols as well as peer group communication. In the classical design of group key protocols, each peer should be authenticated by a separate and centralized authentication server (e.g. Kerberos). Although many practical protocols present efficient ways for authentication, we are still facing the necessity of optimization between authentication and group key sharing. In that sense, implicit key authentication is an ideal property for group key protocols since, once it is possibly put into practice, we do not need any separate authentication procedure as a requisite. There was an attempt to devise implicit key authentication service in conjunction with group key agreement protocol; Authenticated Group Diffie-Hellman (A-GDH) and its stronger version (SA-GDH). Unfortunately...