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Pan F.,Guangdong Key Laboratory of Information Security Technology | Huang J.,Sun Yat Sen University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

People can make highly photorealistic images using rendering technology of computer graphics. It is difficult to human eye to distinguish these images from real photo images. If an image is photorealistic graphics, it is highly possible that the content of the image was made up by human and the reliability of it becomes low. This research field belongs to passive-blind image authentication. Identifying computer graphics images is an important problem in image classification, too. In this paper, we propose using HMT(hidden Markov tree) to classifying natural images and computer graphics images. A set of features are derived from HMT model parameters and its effect is verified by experiment. The average accuracy is up to 84.6%. © 2011 Springer-Verlag. Source


Lei Y.,Sun Yat Sen University | Luo W.,Sun Yat Sen University | Luo W.,Guangdong Key Laboratory of Information Security Technology | Wang Y.,Sun Yat Sen University | Huang J.,Sun Yat Sen University
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2012

Video sequence matching aims to locate a query video clip in a video database. It plays an important role in reducing storage redundancy and detecting video copies for copyright protection. In this paper, we propose an effective method for video sequence matching based on the invariance of color correlation. The proposed method first splits each key-frame into nonoverlapping blocks. For each block, we sort the red, green, and blue color components according to their average intensities, and use the percentage of the color correlation to generate a frame feature with a small size. Finally, the resulting video feature is made up of the consecutive frame features, which is demonstrated to be robust against most typical video content-preserving operations, including geometric distortion, blurring, noise contamination, contrast enhancement, and strong re-encoding. The experimental results show that the proposed method outperforms the existing methods in the literature, as well as the method based on the traditional color histogram. Furthermore, the time and space complexity of our algorithm are both satisfactory, which are very important for many real-time applications. © 1991-2012 IEEE. Source


Zhang F.G.,Sun Yat Sen University | Zhang F.G.,Guangdong Key Laboratory of Information Security Technology
Science in China, Series F: Information Sciences | Year: 2010

In this paper we show that the twisted Ate pairing on elliptic curves can be generalized to hyperelliptic curves, and give a series of variations of the hyperelliptic Ate and twisted Ate pairings. Using the hyperelliptic Ate pairing and twisted Ate pairing, we propose a new approach to speeding up the Weil pairing computation. For some hyperelliptic curves with high degree twist, computing Weil pairing by our approach may be faster than Tate pairing, Ate pairing, and all other known pairings. © 2010 Science China Press and Springer-Verlag Berlin Heidelberg. Source


Dai S.,Sun Yat Sen University | Li H.,Sun Yat Sen University | Zhang F.,Guangdong Key Laboratory of Information Security Technology
Future Generation Computer Systems | Year: 2015

Along with the popularization and rapid development of cloud-computing, more and more individuals and enterprises choose to store their data in cloud servers. However, in order to protect data privacy and deter illegal accesses, the data owner has to encrypt his data before outsourcing it to the cloud server. In this situation, searchable encryption, especially searchable symmetric encryption (SSE) has become one of the most important techniques in cloud-computing area. In the last few years, researchers have presented many secure and efficient SSE schemes. Like traditional encryption, the security of all existing SSE schemes are based on the assumption that the data owner holds a secret key that is unknown to the adversary. Unfortunately, in practice, attackers are often able to obtain some or even all of the data owner's secret keys by a great variety of inexpensive and fast side channel attacks. Facing such attacks, all existing SSE schemes are no longer secure. In this paper, we investigate how to construct secure SSE schemes with the presence of memory attack. We firstly propose the formal definition of memory leakage-resilient searchable symmetric encryption (MLR-SSE, for short). Based on that, we present one adaptive MLR-SSE scheme and one efficient non-adaptive dynamic MLR-SSE scheme based on physical unclonable functions (PUFs), and formally prove their security in terms of our security definitions. © 2015 Elsevier B.V. Source


Zhao X.,Sun Yat Sen University | Zhang F.,Sun Yat Sen University | Zhang F.,Guangdong Key Laboratory of Information Security Technology | Tian H.,Sun Yat Sen University
Ad Hoc Networks | Year: 2011

A group key agreement protocol allows a set of users to establish a common symmetric key via open networks. Dynamic asymmetric group key agreement means that a dynamic set of users form a temporary group and negotiate to share a public encryption key, so that anyone can send message securely and efficiently to the temporary group. Users can join or leave the group efficiently without triggering a completely new key agreement protocol, which will greatly benefit the users in ad hoc networks. We describe a generic construction of dynamic asymmetric group key agreement by combining a conventional authenticated group key agreement, a public key encryption and a multi-signature. Then we give out an instance with constant rounds of interactions and constant transmission cost for each participant. © 2010 Elsevier B.V. All rights reserved. Source

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