Bayesian distance metric learning and its application in automatic speaker recognition systems

This paper proposes state-of the-art Automatic Speaker Recognition System (ASR) based on Bayesian Distance Learning Metric as a feature extractor. In this modeling, I explored the constraints of the distance between modified and simplified i-vector pairs by the same speaker and different speakers. An approximation of the distance metric is used as a weighted covariance matrix from the higher eigenvectors of the covariance matrix, which is used to estimate the posterior distribution of the metric distance. Given a speaker tag, I select the data pair of the different speakers with the highest cosine score to form a set of speaker constraints. This collection captures the most discriminating variability between the speakers in the training data. This Bayesian distance learning approach achieves better performance than the most advanced methods. Furthermore, this method is insensitive to normalization compared to cosine scores. This method is very effective in the case of limited training data. The modified supervised i-vector based ASR system is evaluated on the NIST SRE 2008 database. The best performance of the combined cosine score EER 1.767% obtained using LDA200 + NCA200 + LDA200, and the best performance of Bayes_dml EER 1.775% obtained using LDA200 + NCA200 + LDA100. Bayesian_dml overcomes the combined norm of cosine scores and is the best result of the short2-short3 condition report for NIST SRE 2008 data

XSS attack detection based on machine learning

As the popularity of web-based applications grows, so does the number of individuals who use them. The vulnerabilities of those programs, however, remain a concern. Cross-site scripting is a very prevalent assault that is simple to launch but difficult to defend against. That is why it is being studied. The current study focuses on artificial systems, such as machine learning, which can function without human interaction. As technology advances, the need for maintenance is increasing. Those maintenance systems, on the other hand, are becoming more complex. This is why machine learning technologies are becoming increasingly important in our daily lives. This study use supervised machine learning to protect against cross-site scripting, which allows the computer to find an algorithm that can identify vulnerabilities. A large collection of datasets serves as the foundation for this technique. The model will be equipped with functions extracted from datasets that will allow it to learn the model of such an attack by filtering it using common Javascript symbols or possible Document Object Model (DOM) syntax. As long as the research continues, the best conjugate algorithms will be discovered that can successfully fight against cross-site scripting. It will do multiple comparisons between different classification methods on their own or in combination to determine which one performs the best.À medida que a popularidade dos aplicativos da internet cresce, aumenta também o número de indivíduos que os utilizam. No entanto, as vulnerabilidades desses programas continuam a ser uma preocupação para o uso da internet no dia-a-dia. O cross-site scripting é um ataque muito comum que é simples de lançar, mas difícil de-se defender. Por isso, é importante que este ataque possa ser estudado. A tese atual concentra-se em sistemas baseados na utilização de inteligência artificial e Aprendizagem Automática (ML), que podem funcionar sem interação humana. À medida que a tecnologia avança, a necessidade de manutenção também vai aumentando. Por outro lado, estes sistemas vão tornando-se cada vez mais complexos. É, por isso, que as técnicas de machine learning torna-se cada vez mais importantes nas nossas vidas diárias. Este trabalho baseia-se na utilização de Aprendizagem Automática para proteger contra o ataque cross-site scripting, o que permite ao computador encontrar um algoritmo que tem a possibilidade de identificar as vulnerabilidades. Uma grande coleção de conjuntos de dados serve como a base para a abordagem proposta. A máquina virá ser equipada com o processamento de linguagem natural, o que lhe permite a aprendizagem do padrão de tal ataque e filtrando-o com o uso da mesma linguagem, javascript, que é possível usar para controlar os objectos DOM (Document Object Model). Enquanto a pesquisa continua, os melhores algoritmos conjugados serão descobertos para que possam prever com sucesso contra estes ataques. O estudo fará várias comparações entre diferentes métodos de classificação por si só ou em combinação para determinar o que tiver melhor desempenho

Trends on Computer Security: Cryptography, User Authentication, Denial of Service and Intrusion Detection

The new generation of security threats has beenpromoted by digital currencies and real-time applications, whereall users develop new ways to communicate on the Internet.Security has evolved in the need of privacy and anonymity forall users and his portable devices. New technologies in everyfield prove that users need security features integrated into theircommunication applications, parallel systems for mobile devices,internet, and identity management. This review presents the keyconcepts of the main areas in computer security and how it hasevolved in the last years. This work focuses on cryptography,user authentication, denial of service attacks, intrusion detectionand firewalls

Continuous User Authentication Using Multi-Modal Biometrics

It is commonly acknowledged that mobile devices now form an integral part of an individual’s everyday life. The modern mobile handheld devices are capable to provide a wide range of services and applications over multiple networks. With the increasing capability and accessibility, they introduce additional demands in term of security. This thesis explores the need for authentication on mobile devices and proposes a novel mechanism to improve the current techniques. The research begins with an intensive review of mobile technologies and the current security challenges that mobile devices experience to illustrate the imperative of authentication on mobile devices. The research then highlights the existing authentication mechanism and a wide range of weakness. To this end, biometric approaches are identified as an appropriate solution an opportunity for security to be maintained beyond point-of-entry. Indeed, by utilising behaviour biometric techniques, the authentication mechanism can be performed in a continuous and transparent fashion. This research investigated three behavioural biometric techniques based on SMS texting activities and messages, looking to apply these techniques as a multi-modal biometric authentication method for mobile devices. The results showed that linguistic profiling; keystroke dynamics and behaviour profiling can be used to discriminate users with overall Equal Error Rates (EER) 12.8%, 20.8% and 9.2% respectively. By using a combination of biometrics, the results showed clearly that the classification performance is better than using single biometric technique achieving EER 3.3%. Based on these findings, a novel architecture of multi-modal biometric authentication on mobile devices is proposed. The framework is able to provide a robust, continuous and transparent authentication in standalone and server-client modes regardless of mobile hardware configuration. The framework is able to continuously maintain the security status of the devices. With a high level of security status, users are permitted to access sensitive services and data. On the other hand, with the low level of security, users are required to re-authenticate before accessing sensitive service or data

Effective Identity Management on Mobile Devices Using Multi-Sensor Measurements

Due to the dramatic increase in popularity of mobile devices in the past decade, sensitive user information is stored and accessed on these devices every day. Securing sensitive data stored and accessed from mobile devices, makes user-identity management a problem of paramount importance. The tension between security and usability renders the task of user-identity verification on mobile devices challenging. Meanwhile, an appropriate identity management approach is missing since most existing technologies for user-identity verification are either one-shot user verification or only work in restricted controlled environments. To solve the aforementioned problems, we investigated and sought approaches from the sensor data generated by human-mobile interactions. The data are collected from the on-board sensors, including voice data from microphone, acceleration data from accelerometer, angular acceleration data from gyroscope, magnetic force data from magnetometer, and multi-touch gesture input data from touchscreen. We studied the feasibility of extracting biometric and behaviour features from the on-board sensor data and how to efficiently employ the features extracted to perform user-identity verification on the smartphone device. Based on the experimental results of the single-sensor modalities, we further investigated how to integrate them with hardware such as fingerprint and Trust Zone to practically fulfill a usable identity management system for both local application and remote services control. User studies and on-device testing sessions were held for privacy and usability evaluation.Computer Science, Department o

Biometrics

Biometrics uses methods for unique recognition of humans based upon one or more intrinsic physical or behavioral traits. In computer science, particularly, biometrics is used as a form of identity access management and access control. It is also used to identify individuals in groups that are under surveillance. The book consists of 13 chapters, each focusing on a certain aspect of the problem. The book chapters are divided into three sections: physical biometrics, behavioral biometrics and medical biometrics. The key objective of the book is to provide comprehensive reference and text on human authentication and people identity verification from both physiological, behavioural and other points of view. It aims to publish new insights into current innovations in computer systems and technology for biometrics development and its applications. The book was reviewed by the editor Dr. Jucheng Yang, and many of the guest editors, such as Dr. Girija Chetty, Dr. Norman Poh, Dr. Loris Nanni, Dr. Jianjiang Feng, Dr. Dongsun Park, Dr. Sook Yoon and so on, who also made a significant contribution to the book