الفهرس 
Chapter 1: IntroductionOnly 14 pages are availabe for public view
 |  | from | 149 |  |  |
| | | from | 149 | | |
Abstract
Recently, digital communication and storage over the Internet through the cloud increases in a rapid speed. Accordingly, data security becomes a vital issue as there are many hackers who want to steal or alter others’ private data. Fog computing comes to secure and facilitate the connection to the cloud environment. Fog computing has become a fast intermediate between the cloud and the internet of things (IOT) devices. So, the communication channel between the fog and IOT devices must be secured against attacks. Many efforts have been done to secure the fog through the use of steganography to embed important data into a cover digital medium and cryptography to encrypt the data into a meaningless form. Both Cryptography and steganography are well-known techniques for data security. Each of them has its own advantages and strength points, hence, combining Cryptography and steganography in a hybrid system certainly promotes the system’s level of security. Although several hybrid security strategies have been proposed, they still suffer from many hurdles especially when they are applied to fog environments. Fog computing requires not only a high security level but also a real time transmission. Hence, recent hybrid security strategies cannot be applied directly to fog environments as they suffer from long processing time. The main objective in this work is to develop and propose new hybrid strategies for data security through fog computing. Both cryptography and steganography are merged to achieve high imperceptibility. Cryptography applied by two different methods as in first strategy a Linear Feed Back Shift Register (LFSR) merged with an Adder/subtractor and non-linear function. While cryptography in the second strategy performed into two phases based on Fast Programmable Linear Feed Back Shift Register (FPLFSR). On the other hand, steganography in the first strategy performed in wavelet transform domain, while the latter use steganography in the spatial domain. Both of the strategies have proved their efficiency. Two different hybrid strategies are proposed which are called hybrid security strategy (HS2) and Fog Based Security Strategy (FBS2).