ISSN: 2229-371X
Hussain Abo Surrah1, Isbudeen Noor Mohamed2 College of Computers and Information Technology, Taif University, KSA. |
Corresponding Author: Hussain Abo Surrah, E-mail: salama366@yahoo.com, isbudeen@hotmail.com |
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Steganography is the art or practice of concealing a message, image, or file within another message, image, or file. It serves as a better method of securing message than cryptography which only conceals the content of the message not the existence of the message. This means that, the original message is being hidden within a carrier such that the changes so occurred in the carrier are not observable. In this paper, we proposed a new steganography scheme for hiding a piece of critical information in a host binary image. The proposed scheme presents a new form of weight matrix and a secret key. The weight matrix is dynamic that is it changes its position at every block of the image to increase the security. The performance of the proposed scheme is compared with that of the Chen et al scheme (CPT scheme). The results show that our scheme provides a higher security, and hides a higher amount of data than CPT scheme, and it keeps that same quality level of the host image as the CPT scheme.
Keywords |
Binary image processing, Datahiding, PSNR, Steganography |
INTRODUCTION |
As digital media became easily accessed, copied, multiplied without information loss, and manipulate it without detection, their security-related issues become a greater concern. One main issue is confidentiality, which is typically achieved by encryption. Ciphering doesn’t allow any modification on any image or audio content. It is unsuitable for verifying the ownership of images and audio[2]. Information hiding is the process of inserting secret data into digital media by modifying original multimedia content to distract opponent’s attention [1,2,3]. One less confusing name for data hiding is the steganography. Steganography would be combined with encryption to achieve a higher level of security. The application of data hiding can be used in military, commercial, and anti-criminal-related and so forth [6,7]. Classification of information hiding techniques can be found in [8,4,5]. The most common used technique for data hiding in the gray images is the least significant bit (LSB)[12]. A genetic algorithm is proposed in [13]to degrade the quality of the image. A hiding scheme base donkey stream generator is proposed in [6,12]. It considers show to apply the public key cryptography to steganography. On the other hand, very little research had been done for data hiding in binary images, since each pixel in binary images requires only one bit to represent it, and the changing in any pixel can be easily detected [9,10,11]. |
The CPT scheme [14] proposed a Secure data hiding algorithm that cannot only embed a great deal of secret information into binary images but also ha imperceptible quality. In that scheme the authors proposed a secret key, and a weight matrix to protect the secret data and increased the capacity of data that can be hidden in an image block of size m×n in to log2[m×n+1].In this paper, we propose a modified steganography scheme for hiding apiece of critical information in a host binary image. A secret key and a weight matrix are used to protect the hidden data. Given an image block of size m×n, the proposed scheme can hide as many as log 2 [m×n+1]+1 bits of data in the host image by changing at most 2 bits. This scheme is compared to the CPT scheme [14]. From the comparison, it is easy to see that, the proposed scheme can provide higher security, embed more data than the CPT scheme, and maintain the same quality of the stego image. |
This paper is organized as follows: Section 2, presents the description and the assumptions of CPT scheme. Section 3. Presents the proposed algorithm. Section 4., describes, analyzes and compares the results obtained using the proposed and the CPT algorithms. Finally, Section 5. Summarizes this paper. |
REVIEWS AND MOTIVATIONS |
In this section, we present the data hiding scheme which introduced by Chen et al [14], and is abbreviated as CPT scheme. A block diagram of this scheme is shown in Fig.1. In the CPT scheme, given a host binary image F.F will be partitioned in to block suffixed sizem×n(for simplicity, assume that F’s size is a multiple of m×n). The scheme is able to hide as many as r≤log2 [m×n+1] bits of secret data in each host block by modifying at most 2 bits in the block. The secret key has two components: |
a. K:is a randomly selected binary matrix of size m×n |
b. W: weight matrix which is an integer matrix of size m×n. It satisfies equation(1): |
THEPROPOSEDALGORITHM |
In this section, we present a new data hiding scheme. The inputs to this scheme are: |
a. F: a host bitmap image F which is partitioned in to block so size m×n. |
b. K: a secret key matrix of size m×n shared by the sender and the receiver. |
c. W:a secret weight matrix shared by the sender and the receiver. It is an integer matrix of size m×n. Its elements are from {2r−1···2r−1} at any secret randomly order, where r is the number of embed de db it’s in to m×n block of F. |
d. S: a secret substitute weight transformation, for changing the position for the weight matrix in each hiding block. |
d. S: a secret substitute weight transformation, for changing the position for the weight matrix in each hiding block. |
e. B: some secret information consisting of k×r bits to be embedded in F, where k is the number of m×n block sin F. |
Fig.4 shows a block diagram of the proposed data hiding scheme. |
Dynamic Weight Management: |
The proposed scheme heavily relies on the dynamic weight matrix W to represent the embedded data, and on the substitution matrix S to change the position of the dynamic weight matrix in each embedding block. The following example illustrates how the proposed dynamic secret weight matrix works. Suppose that the size of K, the initial weight matrix W0, and the secret substitution matrix S equal (3×3).Considera3×3firstblockF1of the host image F as shown in Fig.5. We illustrate how the dynamic weight matrix S works in the proposed scheme to embed r=4 bits of data into F1, say this bits are b1b2b3b4. We First perform the bit wise X−OR on F1 and K, and substitute by W0 in the substitution matrix S to get W1, after that we compute (F1 ⊕K) ⊗S(w0) asinFig.6. |
Experimental Results |
The plat form of our research is Celeron 450MHz processor, 256 MBR am, windows XP professional operating system, Matlab programming, and adobephotoshop7. 0 as a graphical tool. In our experiments, we use four 256×256 binary images. These images are Mandrill, geometrical shape, Mickey and English text. We compare the performance of our algorithm with the CPT algorithm from two points so f views: |
a. Quality: quality of the images is determined by row eye judgment, after hiding data in the host binary image. |
b. Capacity: the amount of data that the host m×n block size can hide. |
In Fig., 11, we show the effect of hiding data in the binary image Mandrill using the CPT and the propose algorithm. In the two algorithms, precaution is taken not to hide in the black or white image blocks. Fig.11 (a) presents the original host image. In the figures 11 (b), 11 (c), and 11 (d) we use the CPT algorithm to hide 650 bytes with block size 8×8, 237 bytes with block size 16×16, and 128 bytes with block size 32×32 respectively. Similarly using the proposed algorithm in figures 11 (e), 11 (f), and 11 (g), we hide 653 bytes with block size 8×8, 266 bytes with block size 16×16, and 141 bytes with block size32×32. |
From Fig. 11, it is easy to see that the proposed algorithm hides more data than the CPT algorithm, while keeping the same quality level for the stego image. To ensure these results, we repeated the experiments using the binary images geo metrical shape, Mickey, and English text. In tables 1,2, and 3, we list he capacity that we could hide using the proposed and the CPT algorithms for different block sizes. Based on obtained results, we can say that the proposed algorithm hides more data than the CPT algorithm while keeping the same quality level for stego image. |
CONCLUSIONS |
We have presented a new steganography scheme for hiding data in a host binary image. A secret key, and a new form of dynamic weight matrix were introduced to protect the hidden data, and to increase its capacity. The weight matrix changes its position at every block, as a result, the security |
Figure 11: hiding effect on Mandrill image (a) the original host image, (b) hiding 650 bytes by CPT with block size 8 x 8 , (c) hiding 237 bytes by CPT with block size 16 x 16, (d) hiding 128 bytes by CPT with block by CPT with block size 32 x 32 , (e) hiding 653 bytes by the proposed hiding scheme with block size 8 x 8, (f) hiding 266 bytes by the proposed hiding scheme 16 x 16, (g) hiding 141 bytes by the proposed hiding scheme with block size 32x32Of the proposed hiding scheme is increased. The experimental results show that the proposed scheme can hide more data and have higher security than the CPT scheme while keeping the same quality level of the stego image. Future research could involve encrypting the data before hiding. |
References |
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