Huy Hoang Ngo

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The current paper presents preliminary work towards the integration of the Fujisaki model into the VnVoice Vietnamese TTS system, based on a set of rules to control the F0 contour. A speech corpus consisting of 20 sentences was compiled. Each of the sentences can have various meanings depending on the tone associated with a monosyllabic keyword which it(More)
In the present work, a block cipher is presented which deals with a dynamic symmetric key cryptographic method using substitution and transposition technique. In this work a dynamic secret key is generated using Linear Congruential Generator (LCG). The striking feature of the present work is creation of a new secret key for every pair of encryption and(More)
Authentication is the most important component to protect information system from unauthorized access. Because mobile devices have resource limitations, current existing authentication methods experience security, efficiency, flexibility and scalability problems in wireless network services. Although many access control methods utilize both individuals and(More)
Authorization and authentication services are the major components protecting integrity and authenticity. Authorization control service provides a mechanism to verify user permission to access services. In wireless networks, not only users may change roles but also services can be added, removed or modified more frequently. Although Role-Based Access(More)
This paper presents a new hybrid group key management scheme for sensitive information systems which allows group members to share information securely. By classifying users into two categories, the complexities of rekeying operation on key servers are reduced while privacy for individuals is also protected. A formal analysis is provided to verify the(More)
In modern security models, cryptography plays a fundamental role in protecting data integrity and confidentiality in information systems. However, cryptography itself is subject to cryptanalysis attacks. To reduce the cryptanalysis attack risk, a dynamic key theory is presented and analyzed in this paper. Because these dynamic keys are one-time used(More)
Group key management is an important framework to secure group communications. To improve the performance of re-keying for group key management in large scale systems, logical hierarchical key was proposed. However, this approach does not consider the high re-keying cost of single user having multiple memberships. In this paper, we propose a membership(More)