Research And Implementation Of Multimedia Data Encryption System Based On Virtual-Optics

Information security has become an increasingly important issue and drawn much attention from both research communities and industrial sectors as rapid development of data communications and computer network is leading us into the information era. In past years, several powerful and international standard algorithms for data encryption have been proposed and widely applied in the areas such as commercial transactions and military telecommunications, etc. Recently, optical encryption technology has been a subject of receiving many research efforts because of inherently parallel nature of optical information processing, high security strength and huge freedoms of degrees for key design. Optical security technology has appeared very promising and is likely the next generation of information security. However, at current research stage, the research of optical encryption techniques is still limited in the laboratory due to the lack of cost-effective components and devices for the construction of optical security systems. In addition, analog-to-digital conversion and data transmission are also troublesome problems to be solved. The research objective of this thesis is to seek alternative way to implement the methodology of optical encryption in a digital or electronic manner. We aim at finding out a way to combine both advantages of optical and digital or electronic techniques into an approach. To achieve this goal, we firstly investigate theoretical model of information security based on the concept and methodology of virtual-Optics. Then, we present a new scheme for multimedia data encryption/decryption. We use MATLAB to test the performance of proposed scheme with different types of data such as image, text, and audio. Based on those simulation results, we also make a thorough analysis to the sensitivities of proposed scheme. The space of key design is also estimated. Finally, this thesis reports a strategy of software implementation of virtual optics data security accomplished with Microsoft Visual C++. Another focus point of this thesis is the investigation of design and implementation strategy of virtual optical data encryption with the aid of parallel hardware and parallel software. This is achieved through a parallel digital signal processor (DSP). In order to compensate the parallelism of optical processing, we make full use of parallel hardware architecture and parallel computation structure of the TMS320C6701 DSP, leading to a real-time implementation of proposed scheme. Many optimization techniques such as software pipelining are also adopted to further enhance the efficiency of proposed scheme. With the approach reported in this thesis, we are not only able to take advantages of optical encryption such as high security strength and large freedoms for key design, but also benefit from electronic processing such as high flexibility. The parallelism is compensated via the parallel capability of TMS320C6701 DSP. Experiment results with multimedia data have demonstrated the effectiveness of our approach for virtual optical encryption and decryption.