Encryption And Decryption Mobile Store Data Distribution System

In aiming to meet the requirement of army combat and training, solve the problems that secret information was easily to be captured and decoded, the< Encryption and Decryption Mobile Store Data Distribution System> was developed. 3DES block cipher algorithm with 192-bit keys was adopted in the system, the ciphertext and keys were stored in specialized hardware while only plaintext was in PC.System was made up of two parts, the PCI encryption and decryption board and the mobile carrier. PCI board was mainly divided into three parts, such as 3DES encryption and decryption module, PCI IP core module and USB datatransmission module.3DES module and PCI IP core module were the core of the whole system, realized in FPGA chip. The PCI transport protocol, the design process of PCI IP core were expounded, the theory, procedure and VHDL code implementation of 3DES were described, the chip selection and circuit connection of USB data transmission module were given.The development tool of FPGA was QuartusII8.0.In PCI IP design, the state machine and FIFO module were described in detail, and the simulation result were given.16 rounds operation of 3DES were realized with logic synthesis to make the time encrypting one set of data from 16 periods to 1,and the design process of S-Box and Sub-key production module were given. The PCB printing was designed in 4-layer to be realiable.Software was divided into three parts, the WDM driver program, upper application program and MCU C51 program, developed by DriverStudio2.7 and Visual C++6.0. WDM's action between software and hardware communication, and the mian routine as DriverEntry and AddDevice were expounded. The communication between application program and WDM driver program were analyzed in upper application program. C51 program was mainly in charge of the communicaiton with USB chip CH375B, its work flow and some core source code were given. Some measures such as redundant instruction, state flag and watchdog were adopted in software design process, to enhance system stability, elimate the possible state of program fleet, endless loop and deadhalt. The hardware encryption and decryption was adoped in this system to enhance security of secret information, avoid being captured and decoded, meet the requirement of current combat training and supply the gap of similar domestic products, has a significant military and economic benefit. The test result shows:this system has advantages as stable performance, high integration and easy operation, can protect secret combat information well.