Guangyong Gao

Reversible Data Hiding Using Controlled Contrast Enhancement and Integer Wavelet Transform

The conventional reversible data hiding (RDH) algorithms pursue high Peak-Signal-to-Noise-Ratio (PSNR) at the certain amount of embedding bits. Recently, Wu et al. deemed that the improvement of image visual quality is more important than keeping high PSNR. Based on this viewpoint, they presented a novel RDH scheme, utilizing contrast enhancement to replace the PSNR. However, when a large number of bits are embedded, image contrast is over-enhanced, which introduces obvious distortion for human visual perception. Motivated by this issue, a new RDH scheme is proposed using the controlled contrast enhancement (CCE) and Haar integer wavelet transform (IWT). The proposed scheme has large embedding capacity while maintaining satisfactory visual perception. Experimental results have demonstrated the effectiveness of the proposed scheme.

Bessel-Fourier moment-based robust image zero-watermarking

Aiming to resist various signal processing operations and geometric transformations, this paper proposes a robust zero-watermarking algorithm based on a new image moment called Bessel-Fourier moment. First, image normalization is used for the invariance of translation and scaling, then the magnitudes of Bessel-Fourier moments of normalized image are computed, which have rotation invariance and are used to construct the feature image regarded as watermarking. Experimental results and analyses show that the proposed method has strong robustness to various attacks, such as blurring, JPEG compression, Gaussian noise, rotation, scaling, Stirmark and print_photocopy_scan. Compared to the congener zero-watermarking schemes and Zernike moment, the developed method has better performance.

Reversible data hiding with contrast enhancement and tamper localization for medical images

Digital transmission of medical images often involves hiding crucial information in some parts of the images which should be later extracted to authenticate ownership and identity. In this paper, a new reversible data hiding (RDH) algorithm for medical images is proposed. The primary objective of the algorithm is to achieve contrast enhancement of the region of interest (ROI) without introducing distortion, and achieve tamper localization against attacks on the ROI. First, the background and ROI of the medical image are segmented using Otsus automatic optimal thresholding method. To reduce the visual distortion, an improved scheme for preprocessing is applied to reduce the number of disordered pixels. By expanding the peak-pairs of the ROI histogram, data embedding along with distortion-less contrast enhancement of the ROI is achieved. The feature-bit matrix generated from the ROI is embedded into the least significant bits (LSBs) of the background pixels. At the receiving end, the tampered contents from the ROI of the detected image can be located using a difference matrix between the feature-bit matrix generated from the ROI and that extracted from the background. In the absence of tampering, the original ROI can be completely restored after the embedded data is extracted. Experimental results demonstrate that in comparison with some state-of-the-art RDH algorithms, the proposed algorithm achieves better performance in terms of contrast enhancement of ROI, preserving visual quality of the background and tamper localization.

Composite chaos-based lossless image authentication and tamper localization

To improve the robustness to combined attack of signal processing plus tamper, a composite chaos-based lossless scheme for image authentication and tamper localization is proposed. A non-successive composite chaos (NSCC) is described, and its performance is analysed by some evaluation indicators. Then NSCC is employed to disturb original image and generate chaotic logo, which enhances the security and robustness of lossless image authentication scheme due to the good performance of NSCC in these aspects of randomness, complexity and ability of anti-forecast technology. Experimental results demonstrate that the proposed scheme is not only safe, but also realizes the correct extraction of logo and precise detection of tampered region position and shape under various attacks, especially signal processing plus tamper attack.

Certificateless Signcryption in the Standard Model

Signcryption can realize encryption and signature simultaneously with lower computational costs and communicational overheads than those of the traditional sign-then-encrypt approach. Certificateless cryptosystem solves the key escrow problem in the identity-based cryptosystem and simplifies the public key management in the traditional public key cryptosystem. There have been some certificateless signcryption schemes proposed in the standard model up to now, but all of them are just proposed in a weaker Type I security model, which is weaker than the original security model of Barbosa and Farshim, who proposed the first certificateless signcryption scheme. In this paper, we propose a certificateless signcryption scheme in the standard model by using bilinear pairings, which is Type I secure in the original security model of Barbosa and Farshim and can resist the malicious-but-passive key generation center Type II attack. The proposed scheme is proved confidential assuming the modified decisional bilinear Diffie–Hellman (M-DBDH) problem is hard, and unforgeable assuming the square computational Diffie–Hellman (Squ-CDH) problem is hard. At last, we evaluate its efficiency which shows it is of high efficiency.

Efficient Key Management for IOT Owner in the Cloud

IOT (internet of things) owner may not want their sensitive data to be public in the cloud. However, the client operated by IOT owner may be too lightweight to provide the encryption/decryption service. To remove the issue, we propose a novel solution to minimize the access control cost for IOT owner. First, we present a security model for IOT with minimal cost of IOT owner client without encryption, in which we transfer the encryption/decryption from the client to the cloud. Second, we propose an access control model to minimize the key management cost for IOT owner. Third, we provide an authorization update method to minimize the cost dynamically. In our method, the sensitive data from IOT owner is only available to the authorized user. Each IOT owner needs only to manage a single password, by which the IOT owner can always manage his/her sensitive data and authorization no matter the authorization policy how to change. Experimental results show that our approach significantly outperforms most of existing methods with efficient key management for IOT owner.

An efficient subscription index for publication matching in the cloud

Publish/subscribe has been successfully used in a variety of information dissemination applications. However, in a cloud computing environment, the enormous amount of information results in a very high requirement for the computing performance of a publish/subscribe method. In this paper, we propose an efficient index called Enindex for publish/subscribe matching. First, we group all the subscriptions submitted by subscribers, based on the key attributes (i.e., the most frequent attributes occurring in the subscriptions). Second, we group all the predicates contained in the subscriptions, according to three basic operators: ź (greater),=(equal), and ź (less), so as to remove the repeated predicates, and thus reduce the memory overhead. Finally, we propose an effective index structure to combine the grouped subscriptions together with the grouped predicates. Enindex not only has a small memory overhead, but also can support efficient publish/subscribe matching and online subscription updating. We conduct extensive experiments on synthetic datasets, and the experimental results demonstrate the superiority of the Enindex over state-of-the-art methods in terms of memory overhead and computing efficiency.

Certificate-Based Generalized Ring Signcryption Scheme

Generalized ring signcryption (GRSC) can realize ring signature and ring signcryption functions with only one key pair and one algorithm. It is very useful for a system with a large number of users, or whose function may be changed, or with limited storage space. We give a formal definition and security model of GRSC in the certificate-based cryptosystem setting and propose a concrete scheme by using bilinear pairings. The confidentiality of our scheme can be proved under the GBDH and CDH assumptions and the unforgeability of our scheme can be proved under GDH′ and CDH assumptions in the random oracle model, and what is more, our scheme has unconditional anonymity. Compared with other certificateless ring signcryption schemes that use bilinear pairings, it is a highly efficient one.

Reversible Authentication of Wireless Sensor Network Based on Prediction-Error Histogram and CRC

In this paper, a reversible authentication scheme for wireless sensor network (WSN) is proposed. Firstly, the WSN data stream is divided into some authentication groups, and each authentication group is composed of a generator group and a carrier group. Then the cyclical redundancy check (CRC) code of generator group is produced as the authentication information. In the carrier group, using the prediction-error-based histogram shifting algorithm, the authentication information is reversibly embedded into the fluctuation region of prediction-error histogram (PEH), not the smooth region. Experimental results and analysis demonstrate that compared with previous schemes, the proposed scheme achieves better performances on computation complex, false tampering alarm and attraction to attackers.

Reversible authentication scheme based on prediction-error expansion with compound symbolic chaos

In this paper, a reversible authentication scheme based on prediction-error expansion (PEE) is proposed. Firstly, the compound symbolic chaos sequence as well as image block pixel bits and position-bits are input into a hash function to produce hash-bits. Then exclusive-or operation, between the label-bits taken from the chaos sequence and hash-bits, is performed to generate the check bits, which are embedded into the image as short watermarking using PEE method. For each block, the observations are achieved by compressed sensing (CS), which are registered in the intellectual property rights (IPR) database as long watermarking. At receiver side, image integrity authentication and tamper localization are determined by the generated label-bits. The blocks without being tampered can be recovered reversibly to original state, and the tampered blocks can be restored using CS reconstruction algorithm with the extracted long watermarking. Experimental results demonstrate the proposed scheme outperforms some state-of-the-art similar schemes.