Design and Implementation of Encryption System for Mobile Hard Disk

At present,in order to solve the data leakage of a hardware encryption system for mobile hard disk and the changing key that is not flexible,the hardware encryption system for mobile hard disk drive based on FPGA—AES system is designed and implemented.This method not only achieves the real-time encryption for the data of the mobile hard disk,but also modifies the key according to the need. Meanwhile,it can destroy the key after data encryption.Experimental results show this method improves the efficiency of data encryption,the security and the reliability.At last,making procedure take up general resource 50% by QuartusII 11.0 development tools enhances the resource utilization ratio. Introduction With the rapid development of information technology and digital society,it is an increasing needs of Information security storage,especially civil and criminal judicial investigation during which the proportion of forensic evidence is more and more big in electronic document forms,and how to solve the divulgence of secret data on mobile hard disk may be the one mostly concerned.Meanwhile,information security storage also has important significance in National defense and military and other special areas. However, at present, Most of the mobile hard disk use the algorithm of MD5,SHA-1and DES,but These algorithms have been decoded by experts at home and abroad and cann’t ensure data security,so most of the data on the hard disk is encrypted by using the software of AES encryption which bases on computer. Although AES disk algorithm is published in domestic or foreign journals, but the key is fixed in the hard disk—not only makes key change not agile but also gives data reveal certain risks once the data loss[1][2].In order to solve these problems,this article introduces an FPGA combined with USB interface,AES encryption technology and EDA technology,and designs the hardware encryption system for mobile hard disk drive based on FPGA. In addition, without using of computer hardware resource condition,it realizes data copy to a mobile hard disk real-time encryption. In this paper,AES core module is analysed and designed emphatically.According to the needs,any key is changed in order to achieve effectively for hard disk data protection and this paper uses of QuartusII 11.0 software to program the line optimization.The overall design of mobile hard disk encryption system The system mainly composed of the main modules of this system includes: the main control module, the AES algorithm module, the USB interface module, the ATA interface module, SRAM and the voltage conversion circuit[3][4][5].Block diagram of the system structure is as shown in Fig.1. 2nd International Conference on Science and Social Research (ICSSR 2013) © 2013. The authors Published by Atlantis Press 808 Fig.1 Block diagram of the system structure To begin with, This system set up key.Furthermore, it through the USB port will transmit data to the FPGA.Meanwhile,according to the SEA algorithm, FPGA encrypt data.At last,it copy encrypted data to ATA hard disk interface. This design lays emphasis on the research of the AES algorithm module design,implementation and function,which bases on the peripheral conventional circuit platform. The detailed design of AES algorithm module This design uses 128 key algorithm. The core module of AES algorithm consistes of four parts as follows: key expansion module, subBytes module, shiftRows module and mixColumns module[5][6]. A 128 bit data block complete a encryption process is as shown in Fig.2. Fig.2 FPGA internal AES working principle 1. Key expansion module The module employs Non-parallel extensions to expand the key in order to turn 128 key into 128 x 11 key sequence. It involves three kinds of operations—Subword,Rotword and Rcon and the array pointer arithmetic. It gets a new array Round_key[11] after full key extensions. Finally,this way gets