Keywords : DCT

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.

Use the Frequency Domain to Hide in Some Audio Files

Zahraa Tarik; Farah T. Mohammd; Ikhlass Thanoon; Azhar Rafie

AL-Rafidain Journal of Computer Sciences and Mathematics, 2013, Volume 10, Issue 1, Pages 275-284
DOI: 10.33899/csmj.2013.163458

In this work, anew hiding algorithm is proposed that depends on using two deferent domain (spatial and frequency) to achieve and provide security and protection for transformed data, which is represented in a text message encrypted using a key of direct standard method, then spatial domain were use to hide it inside an audio file, Using Discrete cosine transform (DCT) this file has been hidden inside a host audio file. The data of the text message has been fully retrieved after decrypting process, the value of normalization correlation is equal to one.

Hybrid hiding in multimedia files

Farah Tareq Mohammed

AL-Rafidain Journal of Computer Sciences and Mathematics, 2012, Volume 9, Issue 1, Pages 175-185
DOI: 10.33899/csmj.2012.163695

The principle of hybrid information hiding represented by process of information hiding  message (multimedia files) embedded inside another message which is depended on hiding a certain media in another media using different domains (special domain, frequency domain) to provide protection and security for transformed data,  this paper  suggest an algorithm by using two different files first one compressed binary image, the compression method is run-length and hided this file inside the hostage media by use frequency domain which is represented by Discrete cosine transform (DCT), the second is text ciphered by Caesar method which is depended one secret key by using spatial domain.
The data has been retrieved with no error for both text and binary image after deciphering and decompress process completed; the value of normalization correlation factor for both of them is equal to one.

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.

Hybrid intelligent watermark System

Fardos Adnan Abdalkader; Shahbaa I. Khaleel; Nada N. Saleem

AL-Rafidain Journal of Computer Sciences and Mathematics, 2010, Volume 7, Issue 2, Pages 125-138
DOI: 10.33899/csmj.2010.163902

As a result of the development in data transfer technology a cross multimedia and internet, it has became possible to access and copy these information in unauthentical manner . This leads to penetrate digital multimedia security problem.
In this research a hybrid method is designed to protect product from unauthentication access using watermark technique with digital images, these images represent the important part in information systems and many applications. The method indicates hiding the watermark in both spatial and frequency domains using Artificial Intelligent techniques, such as neural networks and genetic algorithms by dividing the watermark depending on the important information contents. The basic important part hides in frequency domain and the second part in spatial domain using Discreet Cosine Transform DCT and Least Significant Bit LSB.
The method efficiency is measured using Peak Signal –to-Noise Ratio PSNR and Normalized Correlation Coefficient NC , Also many attacks is used to measured the watermark robustness and feasibility.