Keywords : DWT

Chaotic Image Steganography using DCT and DWT

Nadia M. Mohammed

AL-Rafidain Journal of Computer Sciences and Mathematics, 2013, Volume 10, Issue 3, Pages 61-73
DOI: 10.33899/csmj.2013.163536

The researchers was interest in the issue of security from long time ago  even  arrived to the current age (the digital age), and because of the importance of this topic and the challenges in it, so this work which included  study and application of new algorithm is proposed to achieve a high level of  security by encrypting the secret message  (image) using the Logistic  Chaotic  function  after the implementation of  Discrete Wavelet Transform (DWT). In the next  phase, it has been implemented the  Discrete Cosine Transform (DCT)  on the cover (image) and then hide the secret message within encrypted data in which  the adoption of the principle of random Blocks which is determined  by  chaotic series.
Deliberately proposed algorithm to provide more of an advantage in it's work, provide ingreliability through data encryption,  message  security, and provided a very high degree of security  through the adoption of the principle of random selected passages  Chaotic, increasing the efficiency of the work of the algorithm and the degree of security.
After the application it must be the use of performance measurements,  so the following was used (NC, BER, PSNR, MSE). The language was  Matlab9.

Digital Image Watermarking Scheme Using Discrete Wavelet Transform Domain, Quantization, and Genetic Algorithm

Nasseer Basheer; Shaymaa S Abdulsalam

AL-Rafidain Journal of Computer Sciences and Mathematics, 2013, Volume 10, Issue 1, Pages 13-27
DOI: 10.33899/csmj.2013.163421

Protection of digital multimedia content has become an increasingly important issue for content owners and service providers. Watermarking is identified as a major means to achieve copyright protection. The algorithm proposed in this work, is to use a blind watermarking scheme based on the Discrete Wavelet Transform (DWT). Watermark components are embedded in the LL subband of the 4th DWT level of the host image by quantizing coefficients of the LL subband to improve the watermark robustness. The Genetic Algorithm (GA) is used for optimizing the quantization step size parameter, and the strength of factors. The host image used is a 512×512 gray scale image and the watermark image is a 32×32 binary logo. The proposed scheme was tested against mostly known threats and it proves to give good robustness. Also, it still gives a high quality watermarked image. MATLAB Program was used to perform the watermarking task.

Chaotic Encryption Based on Biometric Key

Saja J. Mohammed; Melad jader saeed; Ielaf O. Abdul Majjed

AL-Rafidain Journal of Computer Sciences and Mathematics, 2010, Volume 7, Issue 3, Pages 183-198
DOI: 10.33899/csmj.2010.163937

In this paper a new algorithm is suggested to encrypt data, as it was to benefit from human iris as one of Biometric properties in human body which distinguish the individual from the other to produce the encryption through extracting important features using Wavelet Transformation and then passing through a series of  operations moderation as the first phase, at the second phase a chaotic function properties is used by leading it in encryption operation as a basic factor.
Through the overlap between the results of above  phases a new encryption  algorithm is produced which show  strength, and could not discover the encryption key until  getting  the biometric property and  finding complete information about the chaotic used function  in addition to the working algorithm .

Multistage Hiding Image Techniques

Nadia M. Mohammed

AL-Rafidain Journal of Computer Sciences and Mathematics, 2010, Volume 7, Issue 2, Pages 151-166
DOI: 10.33899/csmj.2010.163893

In the few recent years computer sciences have been widely developed especially in communication spaces and Internet, therefore, a great need appear for security and safety of our information. Steganography is the science of hiding information or data (like a secret message) in other cover (like a digital image) in such a way that a normal person can't sense it.
In this paper, four new methods were suggested in steganography systems to embed secret data in compressed images. Two methods are working in spatial domain, known as moving window and odd/even LSB, others are working in transform domain, known as odd/even DCT and DCT+DWT.
The comparison results present that new methods are better than traditional methods in many characteristics, like (efficiency, security level, imperceptibility and robustness). The work was implemented using Matlab.

Voice Security Using Hybrid Algorithm

Alyaa Moufaq Abdul Majeed Haleem

AL-Rafidain Journal of Computer Sciences and Mathematics, 2010, Volume 7, Issue 2, Pages 107-118
DOI: 10.33899/csmj.2010.163889

This research deals with constructing and implementing a new digital voice security Algorithm based on hiding large amount of data (sound file) in a 24 bits host color image (RGB image). The proposed method starts with speech compression to convert human speech into an efficiently encoded representation that can later be decoded to produce a close approximation of the original signal. The process of compression is achieved by first computing Discrete Wavelet Transform (DWT), truncating small-valued coefficients and then efficiently encoding them. The stream bits output from coder are encrypted using Linear Feedback Shift Register (LFSR) algorithm. These enciphered bits are then embedded into the image blocks. A binary key matrix and weight matrix are used as a secret key to protect the hidden information. The algorithm can hide as many as  bits of data in the image by changing one bit in each block of size . High security algorithm was achieved using three layers to make it difficult to break by attacker. The algorithm has been implemented using MATLAB.