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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.


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.


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.


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.


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

Broadcast encryption provides a convenient method to distribute digital content to subscribers over an insecure broadcast channel. Traitor tracing is needed because some users may give out their decryption keys to construct pirate decoders. There are many traitor tracing schemes based on collusion secure codes and identifiable parent property codes. However, these schemes are subject to public collaboration of traitors, which is presented by Billet and Phan in EUROCRYPT 2009 as an attack against code-based traitor tracing schemes. In this paper, we describe a generic collusion secure codes based scheme secure against such collaboration. Our scheme is motivated by the idea of identity-based encryption with wildcards (WIBE). We regard the collusion secure codeword for each user as his/her identity, and issue private key accordingly. When in broadcasting, we use a special pattern of WIBE, namely all bit positions in the codewords of intended receivers are set as wildcards. When in tracing, we use another special pattern of WIBE, namely all positions are set as wildcards except the tracing position. By using WIBE, each user is issued one decryption key which should be used as a whole and any incomplete part of the key is useless, while in previous codes based schemes each user holds a number of keys that can be used separately for different bit positions in the codeword. Thus our scheme is resistant to public collaboration, since if the decryption key is disclosed as a whole, it will immediately lead to the accusation of the very traitor. Our idea fits well for code based traitor tracing schemes, no matter collusion secure codes or identifiable parent property codes. We also provide an instance based on Boneh-Boyen-Goh WIBE scheme, achieving constant private key storage cost for each user. Our scheme presents an answer to the problem left open by Billet and Phan. © 2011 Springer-Verlag Berlin Heidelberg.


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.


Zhang B.,Sun Yat Sen University | Zhang B.,Guangdong Key Laboratory of Information Security Technology | Zhang F.,Sun Yat Sen University | Zhang F.,Guangdong Key Laboratory of Information Security Technology
Journal of Network and Computer Applications | Year: 2011

Since Boneh et al. proposed the notion and construction of Public Key Encryption with Keyword Search (PEKS) scheme, many revisions and extensions have been given. Conjunctive keyword search is one of these extensions, however, most of these constructed schemes can not solve conjunctive with subset keywords search function. Subset keywords search means that the receiver could query the subset keywords of all the keywords embedded in the ciphertext. In this paper, we study the problem of conjunctive with subset keywords search function, discuss the drawbacks about the existed schemes, and then give out a more efficient construction of Public Key Encryption with Conjunctive-Subset Keywords Search (PECSK) scheme. A comparison with other schemes about efficiency will be presented. We also list the security requirements of our scheme, then give out the security analysis. © 2010 Elsevier Ltd. All rights reserved.


Zhao X.,Sun Yat Sen University | Zhao X.,Guangdong Key Laboratory of Information Security Technology | Zhang F.,Sun Yat Sen University | Zhang F.,Guangdong Key Laboratory of Information Security Technology
Informatica (Ljubljana) | Year: 2012

People in authority may want to submit some messages anonymously on a famous website, while the maintainers may want to limit the times each person can submit messages on the website so as to save the storage space. More over, when people abuse the system, the maintainers want to find ways to identify their identities. To realize such a system, what we need are some methods that can protect users' privacy, control their access times, and at the same time can identify malicious users when abuses are found. Current signature schemes or credential systems cannot fully achieve above purpose. A single-verifier k-times group signature scheme is proposed, adding times limited property to the group signature scheme. It allows a user to issue group signatures to the only verifier up to k i times for period T i. We use online tracing method to restrict each user to k i signatures strictly, and use the tracing ability of group signature to identify those who abuse the system. Based on it, we can construct times limited accountable anonymous online submission control system for websites. Within allowed times, people can submit articles anonymously, even website maintainers cannot identify two articles are from the same person. When a person posts more than the allowed times, his submission will be rejected. When abuse is found, website maintainers can send the signature to the corresponding open authority to find out the identity.


Zhao X.,Sun Yat Sen University | Zhao X.,Guangdong Key Laboratory of Information Security Technology | Zhang F.,Sun Yat Sen University | Zhang F.,Guangdong Key Laboratory of Information Security Technology
Computers and Security | Year: 2012

Broadcast encryption provides a convenient method to distribute digital content to subscribers over an insecure broadcast channel so that only the qualified users can recover the data. Currently, there are only two broadcast encryption schemes designed for users with different privileges. In these schemes, users with higher privileges can decrypt more contents than those with low privileges, which is quite suitable for applications with different service levels. However, both schemes do not provide traitor tracing strategy. In this paper, we present a traitor tracing and revoking system for different privileges against pirate rebroadcast. We improve the tree structure and the media key block proposed by Jin and Lotspiech to suitable for applications with dynamic services, and then combine them with dynamic traitor tracing and revoking method by Kiayias and Pehlivanoglu. Dynamic services mean the users can change their privileges dynamically and the broadcast center can upgrade to hold more/less privileges when needed for marketing, while in both previous schemes the numbers of privileges are determined when the systems are setup and users' privileges are static. Our scheme uses subset cover method to trace and revoke users so that it can trace unlimited numbers of traitors and revoke unlimited numbers of users. © 2011 Elsevier Ltd. All rights reserved.


Wei B.D.,Sun Yat Sen University | Wei B.D.,Guangdong Key Laboratory of Information Security Technology
Applied Mechanics and Materials | Year: 2013

Most of the existing ID-based designated verifier proxy signature schemes are implemented with pairings. The computation of parings is still much more expensive than the common modular multiplications and exponentiations. To obtain better efficiency, we construct an efficient ID-based DVPS scheme without pairings. The scheme is designed based on the hardness of the discrete logarithm problems. It is proven secure against adaptively chosen message attacks, in the random oracle model. © (2013) Trans Tech Publications, Switzerland.

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