105 research outputs found
Privacy-Preserving Distributed Optimization via Subspace Perturbation: A General Framework
As the modern world becomes increasingly digitized and interconnected,
distributed signal processing has proven to be effective in processing its
large volume of data. However, a main challenge limiting the broad use of
distributed signal processing techniques is the issue of privacy in handling
sensitive data. To address this privacy issue, we propose a novel yet general
subspace perturbation method for privacy-preserving distributed optimization,
which allows each node to obtain the desired solution while protecting its
private data. In particular, we show that the dual variables introduced in each
distributed optimizer will not converge in a certain subspace determined by the
graph topology. Additionally, the optimization variable is ensured to converge
to the desired solution, because it is orthogonal to this non-convergent
subspace. We therefore propose to insert noise in the non-convergent subspace
through the dual variable such that the private data are protected, and the
accuracy of the desired solution is completely unaffected. Moreover, the
proposed method is shown to be secure under two widely-used adversary models:
passive and eavesdropping. Furthermore, we consider several distributed
optimizers such as ADMM and PDMM to demonstrate the general applicability of
the proposed method. Finally, we test the performance through a set of
applications. Numerical tests indicate that the proposed method is superior to
existing methods in terms of several parameters like estimated accuracy,
privacy level, communication cost and convergence rate
A NOVEL JOINT PERCEPTUAL ENCRYPTION AND WATERMARKING SCHEME (JPEW) WITHIN JPEG FRAMEWORK
Due to the rapid growth in internet and multimedia technologies, many new
commercial applications like video on demand (VOD), pay-per-view and real-time
multimedia broadcast etc, have emerged. To ensure the integrity and confidentiality of
the multimedia content, the content is usually watermarked and then encrypted or vice
versa. If the multimedia content needs to be watermarked and encrypted at the same
time, the watermarking function needs to be performed first followed by encryption
function. Hence, if the watermark needs to be extracted then the multimedia data
needs to be decrypted first followed by extraction of the watermark. This results in
large computational overhead. The solution provided in the literature for this problem
is by using what is called partial encryption, in which media data are partitioned into
two parts - one to be watermarked and the other is encrypted. In addition, some
multimedia applications i.e. video on demand (VOD), Pay-TV, pay-per-view etc,
allow multimedia content preview which involves „perceptual‟ encryption wherein all
or some selected part of the content is, perceptually speaking, distorted with an
encryption key. Up till now no joint perceptual encryption and watermarking scheme
has been proposed in the literature.
In this thesis, a novel Joint Perceptual Encryption and Watermarking (JPEW)
scheme is proposed that is integrated within JPEG standard. The design of JPEW
involves the design and development of both perceptual encryption and watermarking
schemes that are integrated in JPEG and feasible within the „partial‟ encryption
framework. The perceptual encryption scheme exploits the energy distribution of AC
components and DC components bitplanes of continuous-tone images and is carried
out by selectively encrypting these AC coefficients and DC components bitplanes.
The encryption itself is based on a chaos-based permutation reported in an earlier
work. Similarly, in contrast to the traditional watermarking schemes, the proposed
watermarking scheme makes use of DC component of the image and it is carried out
by selectively substituting certain bitplanes of DC components with watermark bits.
vi ii
Apart from the aforesaid JPEW, additional perceptual encryption scheme, integrated
in JPEG, has also been proposed. The scheme is outside of joint framework and
implements perceptual encryption on region of interest (ROI) by scrambling the DCT
blocks of the chosen ROI.
The performances of both, perceptual encryption and watermarking schemes are
evaluated and compared with Quantization Index modulation (QIM) based
watermarking scheme and reversible Histogram Spreading (RHS) based perceptual
encryption scheme. The results show that the proposed watermarking scheme is
imperceptible and robust, and suitable for authentication. Similarly, the proposed
perceptual encryption scheme outperforms the RHS based scheme in terms of number
of operations required to achieve a given level of perceptual encryption and provides
control over the amount of perceptual encryption. The overall security of the JPEW
has also been evaluated. Additionally, the performance of proposed separate
perceptual encryption scheme has been thoroughly evaluated in terms of security and
compression efficiency. The scheme is found to be simpler in implementation, have
insignificant effect on compression ratios and provide more options for the selection
of control factor
Lightweight image encryption algorithms: design and evaluation
Doctor of PhilosophyDepartment of Computer ScienceArslan MunirIn an era dominated by increasing use of multimedia data such as images and videos, ensuring the security and confidentiality of images with real-time encryption is of greatest importance. Traditional encryption algorithms are secure, widely used, and recommended, yet they are not suitable nor computationally efficient for encrypting multimedia data due to the large size and high redundancy inherent in multimedia data. Thus, specialized algorithms for multimedia data encryption are needed. This dissertation explores lightweight image encryption algorithms, specifically designed to address time and resource constraints of realtime image encryption while maintaining the confidentiality and integrity of the multimedia data.
The dissertation classifies image encryption based on the techniques used into seven different approaches and analyzes the strengths and weaknesses of each approach. It subsequently introduces and evaluates three novel algorithms designed to encrypt images with low complexity, high efficiency, and reliable security. These algorithms rely on a combination of permutation, substitution, and pseudorandom keystreams to ensure the security of the encrypted images. The first algorithm is based on chaotic systems. The algorithm is implemented using logistic map, permutations, AES S-box, and a plaintext related SHA-2 hash. The second algorithm is based on Trivium cipher. the algorithm is implemented to work on multi-rounds of encryption using pixel-based row and column permutations, and bit-level substitution. For the third algorithm, the Ascon algorithm selected by the National Institute of Standards and Technology (NIST) to standardize lightweight cryptography applications is evaluated for image encryption.
To evaluate the proposed algorithms, a comprehensive set of security, quality, and efficiency valuation metrics is utilized to assess the proposed algorithms and compare them to contemporary image encryption algorithms
Multi-Level Reversible Data Anonymization via Compressive Sensing and Data Hiding
Recent advances in intelligent surveillance systems have enabled a new era of smart monitoring in a wide range of applications from health monitoring to homeland security. However, this boom in data gathering, analyzing and sharing brings in also significant privacy concerns. We propose a Compressive Sensing (CS) based data encryption that is capable of both obfuscating selected sensitive parts of documents and compressively sampling, hence encrypting both sensitive and non-sensitive parts of the document. The scheme uses a data hiding technique on CS-encrypted signal to preserve the one-time use obfuscation matrix. The proposed privacy-preserving approach offers a low-cost multi-tier encryption system that provides different levels of reconstruction quality for different classes of users, e.g., semi-authorized, full-authorized. As a case study, we develop a secure video surveillance system and analyze its performance.publishedVersionPeer reviewe
A NOVEL JOINT PERCEPTUAL ENCRYPTION AND WATERMARKING SCHEME (JPEW) WITHIN JPEG FRAMEWORK
Due to the rapid growth in internet and multimedia technologies, many new
commercial applications like video on demand (VOD), pay-per-view and real-time
multimedia broadcast etc, have emerged. To ensure the integrity and confidentiality of
the multimedia content, the content is usually watermarked and then encrypted or vice
versa. If the multimedia content needs to be watermarked and encrypted at the same
time, the watermarking function needs to be performed first followed by encryption
function. Hence, if the watermark needs to be extracted then the multimedia data
needs to be decrypted first followed by extraction of the watermark. This results in
large computational overhead. The solution provided in the literature for this problem
is by using what is called partial encryption, in which media data are partitioned into
two parts - one to be watermarked and the other is encrypted. In addition, some
multimedia applications i.e. video on demand (VOD), Pay-TV, pay-per-view etc,
allow multimedia content preview which involves „perceptual‟ encryption wherein all
or some selected part of the content is, perceptually speaking, distorted with an
encryption key. Up till now no joint perceptual encryption and watermarking scheme
has been proposed in the literature.
In this thesis, a novel Joint Perceptual Encryption and Watermarking (JPEW)
scheme is proposed that is integrated within JPEG standard. The design of JPEW
involves the design and development of both perceptual encryption and watermarking
schemes that are integrated in JPEG and feasible within the „partial‟ encryption
framework. The perceptual encryption scheme exploits the energy distribution of AC
components and DC components bitplanes of continuous-tone images and is carried
out by selectively encrypting these AC coefficients and DC components bitplanes.
The encryption itself is based on a chaos-based permutation reported in an earlier
work. Similarly, in contrast to the traditional watermarking schemes, the proposed
watermarking scheme makes use of DC component of the image and it is carried out
by selectively substituting certain bitplanes of DC components with watermark bits.
vi ii
Apart from the aforesaid JPEW, additional perceptual encryption scheme, integrated
in JPEG, has also been proposed. The scheme is outside of joint framework and
implements perceptual encryption on region of interest (ROI) by scrambling the DCT
blocks of the chosen ROI.
The performances of both, perceptual encryption and watermarking schemes are
evaluated and compared with Quantization Index modulation (QIM) based
watermarking scheme and reversible Histogram Spreading (RHS) based perceptual
encryption scheme. The results show that the proposed watermarking scheme is
imperceptible and robust, and suitable for authentication. Similarly, the proposed
perceptual encryption scheme outperforms the RHS based scheme in terms of number
of operations required to achieve a given level of perceptual encryption and provides
control over the amount of perceptual encryption. The overall security of the JPEW
has also been evaluated. Additionally, the performance of proposed separate
perceptual encryption scheme has been thoroughly evaluated in terms of security and
compression efficiency. The scheme is found to be simpler in implementation, have
insignificant effect on compression ratios and provide more options for the selection
of control factor
Entropy in Image Analysis III
Image analysis can be applied to rich and assorted scenarios; therefore, the aim of this recent research field is not only to mimic the human vision system. Image analysis is the main methods that computers are using today, and there is body of knowledge that they will be able to manage in a totally unsupervised manner in future, thanks to their artificial intelligence. The articles published in the book clearly show such a future
Application and Theory of Multimedia Signal Processing Using Machine Learning or Advanced Methods
This Special Issue is a book composed by collecting documents published through peer review on the research of various advanced technologies related to applications and theories of signal processing for multimedia systems using ML or advanced methods. Multimedia signals include image, video, audio, character recognition and optimization of communication channels for networks. The specific contents included in this book are data hiding, encryption, object detection, image classification, and character recognition. Academics and colleagues who are interested in these topics will find it interesting to read
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