A new fog based security strategy (FBS2) for reliable image transmission

Abstract

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. 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 suffer from many drawbacks especially when they are applied in fog environments. Fog computing requires not only high security level but also a real time transmission. Hence, recent hybrid security strategies cannot be applied directly in fog environments as they suffer from long processing time. This paper introduces a new Fog Based Security Strategy (FBS2). FBS2 is a hybrid security strategy as it combines Cryptography and steganography techniques. The proposed Cryptography Technique (PCT) is divided into two phases, namely; confusion and diffusion. The former scrambles the secret image pixels, while the latter changes the pixels values using new confusion and diffusion methodologies respectively. Confusion divides the secret images into closed loops of pixels, then rearrange the pixels into straight paths, while diffusion employs a Programmable Linear Feedback Shift Register (PLFSR). On the other hand, the Proposed Steganography Technique is implemented using the discrete wavelet packet transform. Embedding process depends on a new matching procedure, which is based on the most significant bits of both the encrypted secret image and the corresponding employed cover image pixels. Least significant bits (LSBs) are used as indicators to the matching process. At first an intermediate code is derived from the matching process, then, it is encrypted to represent the LSBs of the stego-image. Experimental results have shown that the proposed FBS2 outperforms the previous counterparts in terms of efficiency, security, and processing time, which proves its suitability for application on the fog.