الفهرس 
CHAPTER 1: IntroductionOnly 14 pages are availabe for public view
 |  | from | 119 |  |  |
| | | from | 119 | | |
Abstract
Steganography is a technique of information security that hides
important information. The goal of steganography is to avoid intruders from discovering the important information as it hide the existence of the
information.
In this work, a stegnographyic method is developed based on Jpeg-
Jsteg method to embed a message in a host multimedia signal. This method doesn’t require quantization table. It uses some pre-defined mathematical operation to quantize the DCT coefficient. In this method all the frequency bands of the quantized DCT coefficient became available to hide data in it.
The proposed method include two approaches the first embed message using LSB in all frequency bands while the second embed message using LSB in low and middle frequency bands .It is applied into different type of multimedia such as image and video . Then, it is implemented on Pc and cloud computing. A comparison between the proposed method, Jsteg method and cahng et al’s method is included. The results demonstrated that the capacity of the proposed method is larger than Jsteg method and cahng et al’s method, The proposed method preserving the quality of stego – image where the PSNR value of it is larger than in Jsteg method and cahng et al’s method .Since the maximum capacity in the proposed method is larger than Jsteg method and cahng et al’s method, the processing time of the proposed method is Slight high from Jsteg method and cahng et al’s method. Also we showed by the result that cloud computing features can be used as when our method implemented on cloud computing we used mobility as we can access our method from any place at any time also we obtain better performances when we implement these methods on cloud computing as the processing time for proposed methods is reduced when we used Amazon Ec2 with some specifications that was hard to get in real time.