基于FPGA的图像实时加密系统的设计与实现

发布时间：2018-09-03 15:14

【摘要】：当今信息化时代,无论国家、单位和个人的很多重要信息,都是以数字图形、图像、视频的形式存在。这些图像视频文件的存储和传输,不可避免地面临着被窃取和攻击的危险,因此图像视频文件的加解密研究是信息安全保密研究领域的一个重要研究方向,世界各国都投入了巨大力量从事这方面的理论研究和系统、设备的开发。信息加解密和密码学是一门历史悠久的学科,在不同的历史时期,针对不同的加密数据对象,需要不同的理论及实现方法。本课题针对实时视频数据流,从设计实现成本的角度考虑,综合分析视频流数据特点及其对设计资源的需求,采用一款低成本FPGA开发板,实现了改进的Arnold-Logistic混合加解密算法,设计完成了视频图像实时加密系统并进行了硬件演示验证。论文主要工作包括对视频传输系统结构进行分析,在此基础上,把视频加密系统的设计分作三大步骤来实现:即视频图像直通平台的搭建、视频图像数据流加密模块的设计、系统各个功能模块及最终系统的仿真验证。整体设计工作是基于一款Altera Cyclone II EP2C5Q208C8N FPGA开发板及其开发环境完成的。视频图像直通平台,主要是采用Verilog硬件描述语言设计实现。首先通过FPGA配置CMOS图像传感器OV7670的内部寄存器,使其输出像素为640x480的VGA视频图像数据流;然后FPGA正确捕获送来的视频图像数据,并送到外部64MB的SDRAM芯片中缓存;最后从SDRAM中提取图像数据送到VGA接口驱动模块,驱动外部显示器显示实时视频图像,方便验证直通平台以及后续图像处理后的效果。视频图像数据的加密模块部分,主要采用模型设计方式来实现。首先在Matlab的Simulink平台下,调用DSP Builder工具箱的标准库中模块来搭建正确的图像加密模型;然后调用Signal Compiler模块把DSP Builder模型转换成VHDL硬件描述语言文件,并启动Quartus编译综合、布局布线,最终生成图像加密算法模型脚本文件;最后,在搭建好的视频图像直通平台的工程中调用加密算法模块,完成整个系统的设计。仿真验证工作贯穿在整个设计的各个环节。每个模块以及整个系统都需要经过很多次重复的设计、仿真验证、修改设计工作,最终才能得到性能稳定、功能满足设计指标的系统。设计中主要是通过Modelsim、Quartus II和Simulink中自带仿真验证工具来实现软件仿真,并通过DSP Builder的在线测试以及配置到FPGA中来实现硬件仿真。通过采用自顶向下的设计方法,对系统结构和功能模块进行合理划分,然后分别实现各个子模块,最终搭建实现整体系统。最终,在一片Cyclone II芯片上,实现对CMOS图像传感器采集到的视频图像执行实时流加密操作。
[Abstract]:In the information age, many important information of countries, units and individuals exist in the form of digital graphics, images and videos. The storage and transmission of these image and video files inevitably face the danger of being stolen and attacked. Therefore, the research on encryption and decryption of image and video files is an important research direction in the field of information security and security. Countries all over the world have invested a great deal of energy in this field of theoretical research and system, equipment development. Encryption and decryption of information is a subject with a long history. In different historical periods, different theories and methods are needed for different encrypted data objects. This paper aims at real-time video data flow, considering the cost of design and implementation, synthetically analyzes the characteristics of video stream data and its demand for design resources, and uses a low-cost FPGA development board to realize the improved Arnold-Logistic mixed encryption and decryption algorithm. The real-time encryption system of video image is designed and verified by hardware demonstration. The main work of this paper is to analyze the structure of video transmission system. On this basis, the design of video encryption system is divided into three steps: the construction of video image through platform, the design of video image data stream encryption module. Each function module of the system and the simulation verification of the final system. The whole design work is based on a Altera Cyclone II EP2C5Q208C8N FPGA development board and its development environment. Video image through platform is mainly designed and implemented by Verilog hardware description language. Firstly, the internal register of CMOS image sensor OV7670 is configured by FPGA to output the VGA video image data stream whose pixel is 640x480, and then FPGA correctly captures the sent video image data and sends it to the SDRAM chip of the external 64MB to cache. Finally, the image data is extracted from the SDRAM and sent to the VGA interface driver module to drive the external display to display the real-time video image, which is convenient to verify the effect of the straight-through platform and the subsequent image processing. The encryption module of video image data is mainly implemented by model design. In the Simulink platform of Matlab, the standard library module of the DSP Builder toolbox is called to build the correct image encryption model, and then the DSP Builder model is converted into the VHDL hardware description language file by the Signal Compiler module, and the Quartus compilation and synthesis are started, and the layout and routing are started. Finally, the model script file of image encryption algorithm is generated. Finally, the encryption algorithm module is called in the project of building a good video image through platform to complete the design of the whole system. The simulation and verification work runs through every link of the whole design. Each module and the whole system need many repeated design, simulation verification, modification of the design work, and finally can get a stable performance, function to meet the design specifications of the system. In the design, the software simulation is mainly realized by Modelsim,Quartus II and Simulink, and the hardware simulation is realized by the on-line test of DSP Builder and the configuration of FPGA. By adopting the top-down design method, the system structure and function modules are divided reasonably, and each sub-module is realized, finally the whole system is built and implemented. Finally, real-time stream encryption is implemented on a Cyclone II chip for video images captured by CMOS image sensors.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN791;TP309.7

【相似文献】