Nâng cao hiệu quả và hiệu năng giấu tin trong ảnh số TT tieng anh

Unlike cryptography, data hiding techniques are the science of embedding information into cover digital multimedia, such as images, video, and audio.. The properties of data hiding may b

MINISTRY OF EDUCATION AND TRAINING

CAN THO UNIVERSITY

VÕ PHƯỚC HƯNG

ENHANCING THE CAPACITY AND EFFICIENCY OF

DATA HIDING IN DIGITAL IMAGES

SUMMARY OF DOCTORAL THESIS

MAJOR: INFORMATION SYSTEMS

Major Code: 62480104

CAN THO - 2020

The thesis is completed at:

CAN THO UNIVERSITY

Advisor: Assoc Dr Do Thanh Nghi

The thesis will be defended on the meeting of Univeristy doctoral thesis evaluation council

Place: Doctoral thesis evaluation hall, 2nd floor –

Administration Building, Can Tho University

At hour day month year 2020

The dissertation is available at:

Learning Resource Center, Can Tho University and

The National Library of Vietnam

PUBLICATIONS OF DOCTORAL THESIS

[CT1] Nguyễn Thái Sơn, Võ Phước Hưng, Huỳnh Văn Thanh, Đỗ Thanh Nghị,

“Giấu tin thuận nghịch trong ảnh Stereo với khả năng nhúng tin cao”, Kỉ yếu hội thảo FAIR 2016, pp 631-637

[CT2] P-H Vo, T-S Nguyen, V-T Huynh and T-N Do A robust hybrid

watermarking scheme based on DCT and SVD for copyright protection of Stereo images in proc of NAFOSTED Conf on Information and Computer Science (NICS 2017), 2017, pp 331-335

[CT3] P-H Vo, T-S Nguyen, V-T Huynh and T-N Do A Novel Reversible

Data Hiding Scheme with Two-Dimensional Histogram Shifting Mechanism in

International Journal of Multimedia Tools and Applications, Vol.77(21):

28777-28797, Springer, 2018 [SCIE]

[CT4] Võ Thành C, Võ Phước Hưng, Trầm Hoàng Nam, Nguyễn Thái Sơn,

Đỗ Thanh Nghị, "Một thuật toán thủy vân ảnh số mạnh dựa trên DWT, DCT, SVD và đặc trưng SIFT", Kỉ yếu hội thảo FAIR 2019

[CT5] P-H Vo, T-S Nguyen, V-T Huynh, T-C Vo and T-N Do Secure and

Robust Watermarking Scheme in Frequency Domain Using Chaotic Logistic Map Encoding in proceeding of International Conference on Computer Science, Applied Mathematics and Applications (ICCSAMA 2019), Springer, 2019

[Indexed by Scopus]

[CT6] P-H Vo, T-S Nguyen, V-T Huynh, T-N Do A High capacity invertible

steganography method for Stereo image in the book Digital Media Steganography: Principles, Algorithms, Advances, ELSEVIER Inc., 2020

[Scopus]

CHAPTER 1: INTRODUCTION 1.1 Motivation

The digital transformation evolution has brought about profound changes in our society and our lives More and more digital information is communicated over the network A lot of important information is being exchanged which has attracted the attention of many unauthorized users such as snooping, masquerading or modification Therefore, protecting the security of such information is of considerable concern to many researchers For decades, the researchers have tried to propose methods to avoid the attention of malicious attackers Therefore, the security of the transmitted digital information is guaranteed Unlike cryptography, data hiding techniques are the science of embedding information into cover digital multimedia, such as images, video, and audio The cover image after being embedded with secret data, called stego-image, is still in a meaningful format Therefore, data hiding techniques can avoid attracting attackers’ attention

1.2 Data hiding mechanisms in digital images

Along with powerful software, new device, such as digital cameras and camcorder, high-quality scanner, have reached consumers worldwide to create, manipulate and enjoy multimedia data Thus, in this research, digital images use

as cover objects Moreover, the content of the image also needs to protect the copyright and authentication of the entire The block diagram presentation of a data hiding system is depicted in Fig 1.1

Fig 1.1 Block diagram of a data hiding system

• I′ C: Retrieval image

Embedding procedure, secret message S is embedded into I C based on f Embed

and k Which is formulated as follow

Extracting procedure, the secret message S is retrieved from stego-image I S

based on f Extract and k It can be defined as the following equation (1.2)

(𝑆, 𝐼𝐶′) = 𝑓𝑒𝑥𝑡𝑟𝑎𝑐𝑡(𝐼𝑆, [𝑘]) (1.2)

The embedding process has been well done such that the stego-image I S

looks like the cover image I C The difference between I S and I C is called

distortion Embedded information is extracted from I S image which is based on embedding function Embedding capacity and human visual quality efficiency are evaluated on the properties of the data hiding system Belong to the individual application, the priority of the properties is a different requirement The properties of data hiding may be:

is embedded into the cover image as well as stego-image is maintaining in terms

of human visual quality Moreover, the system is robust against attacks

First, the effectiveness of the embedding scheme can be evaluated by answering questions: (1) Can secret messages embedded in the image be safe? (2) (2) Does the stego-image retain the same quality as the original image? (3) Is

it sure that hidden information is not discovered?

Embedding rate is the second requirement for a data hiding system to increase the number of embedded messages However, embedding capacity and efficiency of the data hiding in a digital image is always the opposite In other words, the more information is embedded, the worse the stego-image quality and vice versa Therefore, it is necessary to study and figure out methods that offer reversibility and high capacity while maintaining an acceptable quality of Stereo images

1.4 Research Objectives

The problem identified in this thesis is to transmit confidential information

on unsafe transmission channels and prevent illegal copies of copyrighted content for the Stereo image In cases, the cryptography technique is not suitable, data hiding is a good alternative method to protect data The main goal of the thesis is to study and propose efficient schemes of data hiding in Stereo images

To archive the goal, the thesis focuses on the following specific objectives:

• Overview of solutions for hiding information in images, analyzing, summarizing the strengths and weaknesses of each solution

• Research on Stereo digital images, compressed images in the spatial domain, and frequency domain to improve analysis, synthesize how to embed information into images

• Research and improve the efficiency and visual stego-image quality as well as retrieve the original image

• Research and propose the robust and secure data hiding schemes for copyright protection of Stereo image

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The proposed methods are proven and implemented on Matlab software

1.6 Contribution of the thesis

The thesis proposes several new approaches to improve the efficiency and performance of hiding information in Stereo images The main contribution of the thesis is improving and developing techniques for hiding information which are invertible system with high embedding capacity in the frequency domain of images In addition, the schemes are secure and robust with resistance to image processing attacks The thesis has contributed new methods in data hiding, which properly archive the trade-off between embedding rate and human visual quality and security and robustness

• A novel reversible data hiding scheme with two-dimensional histogram shifting mechanism,

• A High capacity invertible steganography algorithm using 2-D histogram shifting with EDH

• A robust hybrid watermarking scheme based on DCT and SVD for copyright protection of Stereo images,

• A secure and robust watermarking scheme in the frequency domain using chaotic logistic encoding

1.7 Thesis structure

The thesis is organized into five chapters and an appendix as the following

Chapter 1: Introduction of information secure and confidential information

area How to distinguish the cryptography technique and data hiding technique

Chapter 2: General Overview of the state of data hiding, this chapter

discusses the idea behind information hiding with respect to reversible and reversible steganography and watermarking

non-Chapter 3: This non-Chapter proposes a reversible data hiding technique based

on two-dimensional histogram shifting for quantized discrete cosine transformation coefficients (QDCT) The scheme, a two-dimensional histogram

is constructed by QDCT coefficients blocks with the size of 8×8 of the left image and the right image The QDCT coefficients are selected for embedding data to achieve high embedding capacity

Chapter 4: A robust hybrid watermarking scheme, secure and robust

watermarking schemes are performance which are embedded a logo into image for copyright protection of Stereo image

Chapter 5: Conclusion and future works

2.2 Evaluation metrics for data hiding system

2.2.1 Image visual quality

PSNR is a measure of the visual quality of a stego-image it is measured in decibels (dB) and is one of the most popular techniques to see how much the stego-imge resembles the original image The PSNR is given as equation (2.1)

𝑃𝑆𝑁𝑅 = 10 log10

𝐵2

𝑀𝑆𝐸

(2.1)

where, B is the maximum color boundary of the image, MSE is a deviation of the

stego-image from the original image which is given by the mean square error:

𝑀𝑆𝐸 = 1

𝑀 × 𝑁∑ ∑(𝐼𝑠(𝑥, 𝑦) − 𝐼𝑐(𝑥, 𝑦))

2 𝑁

𝑦=1 𝑀

𝑥=1

(2.2)

with M, N are dimensions of the cover (original) image I C and I S represents the

stego-image ; I C (x,y), I S (x,y) are pixel value at the coordinate (x,y) of I C and I S, respectively

2.2.2 The robustness of watermarked image

To evaluate the robustness property of the watermarking techniques, the bit correlation error (BCR) is used to measure the correction ratio of the extracted watermark image that is defined as equation (2.3)

𝐵𝐶𝑅 =∑ 𝑤̅̅̅̅̅̅̅̅̅̅𝑖⨁𝑤𝑖

𝑛×𝑛 𝑖=1

𝑛 × 𝑛

(2.3)

where 𝑤𝑖 và 𝑤𝑖 are the ith binary value or the original watermark and of the extracted watermark, respectively The notation ⨁ indicates an exclusive-OR operator

2.3 Classification of data hiding techniques

The essential feature of data hiding is to keep communication secure while transmitting stego-image over the network or communication channel Different methods for the system were proposed based on the application and stages included in the embedding process Fig 2.1 illustrated a flowchart of classification data hiding techniques

Fig 2.1 Flowchart of classification data hiding techniques

Non-2.3.1.2 Invertible steganography

In the invertible steganography case, the cover image can be recovered completely without any losses and it matches the original image invertible steganography can be useful when the cover and the secret data are important

2.3.2 Classification based on embedding domain

2.3.2.1 Spatial domain image steganography

The easiest and simplest way of data embedding in digital images is to modify the cover image pixel values in the spatial domain itself These techniques use the cover image pixel intensity value levels directly or indirectly to encode the secret message bits These methodologies fall into some of the simplest mechanisms in terms of embedding and decoding complexity

2.3.2.1 Transform domain image steganography

Transform domain values can also be used for integrating secret bits into a cover image In transform domain-based methods, the secret bits get hidden under the sub-band frequency coefficients The process of embedding and decoding is more complicated in the transform domain rather than the techniques that are used in the time domain This will improve the security of the system Another advantage is that most of the Frequency domain techniques are less affected by the compression, cropping, scaling and rotation attacks Thus, the transform-based systems are more effective in preserving the stego-image quality and makes less detectable in an unsecured channel

2.3.3 Classification based on the cover image dimension

Images can be represented in multiple formats It includes 2-dimensional images, 3-dimensional images of Stereo image

2.3.4 Classification based on machine learning and AI

2.4 Conclusion

This chapter presents a summary of diagrams, architectures and information hiding techniques in digital images that have been studied over the Literature reviews show that the effectiveness of stego-image quality is greatly reduced In other words, the imperceptibility between the embedded image and the original

is not high

The main challenge of any data hiding system in a digital image can be point out carefully and clearly: (i) maintaining stego-image quality to the high level, (ii) recovering the original image after extracting secret messages, (iii) embedding capacity, (iv) Robustness against attacks, (v) security of embedded information

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CHAPTER 3: INVERTIBLE STEGANOGRAPHY

IN FREQUENCY DOMAIN OF STEREO IMAGE

3.2 A Novel Reversible Data Hiding Scheme with Two-Dimensional Histogram Shifting Mechanism

3.2.1 Related works

3.2.2 The proposed method

The research context aims to develop a reversible data hiding method, in which the embedding capacity and human visual quality are improved A reversible data hiding technique based on two-dimensional histogram shifting for quantized discrete cosine transformation coefficients (QDCT) is proposed Which is abbreviated as ĐX1 In the ĐX1 scheme, a two-dimensional histogram

is constructed by QDCT coefficients blocks with the size of 8×8 of the left image and the right image Once most of the QDCT coefficients are located at the top-right corner of the two-dimensional histogram, the QDCT coefficients are selected for embedding data to achieve high embedding capacity In the embedding procedure, the three main steps, i.e., expanding, shifting, and embedding, are only used for QDCT coefficients in this corner not only to gain embedding capacity but also to maintain the good visual quality of stego images The experimental results demonstrated that the proposed method is superior to the previous schemes in terms of embedding capacity and image quality

3.2.2.1 Similar block searching

Since the left and right images of stereo images are considered as a similarity

Thus, the image is decomposed into M×N non-overlapping blocks with a size of

8 × 8 A quantized discrete cosine transform (QDCT) coefficients matrix is

generated by using DCT and JPEG quantization matrix Each block B m,n [m ∈ (0, M-1), n∈(0, N-1)] can be divided into three categories named (a) searching

sector, which contains some lower frequency QDCT coefficients, (b) embedding sector, which contains some middle-frequency QDCT coefficients and (c) non-used sector, which contains the rest of coefficients

3.2.2.2 Two-dimensional histogram shifting based lossless Data embedding

The 2-D histogram denoted as h(x, y), where x and y are the frequencies of

two feature values, belong to the QDCT left and right block Taking advantage

of the similarities of the left and right images in the stereo images, 2D histogram shifting is used for embedding data bits into cover stereo-images, we explored

the coefficients of QDCT located in the embedding area (i.e., 6 ≤ u + v ≤ 9)

quietly approaching zero or positive value

Based on our scheme, the larger the number of zero coefficients is, the greater the embedding capacity is obtained Moreover, the trend of these coefficients commonly gathers at the top-right corner of the histogram (i.e., NE direction) Thus, the 2D shifting and data embedding are conducted at this corner (see Fig 3.1) to achieve high embedding capacity while maintaining the good stego-stereo image quality as shown in the experimental results

(a) Before shifting (b) After shifting