Fpga Based The Md5 Algorithm Hard Disk Read-only Lock

With the development of electronic and communication technology, more and more evidences exist in electronic document forms during the civil and criminal judicial investigation, and the preservation of electronic evidences becomes increasingly demanding. This issue designs a hard disk with read-only lock system based on Altera FPGA hardware implementation. It can be used in judicial detective processes, and applied to protect electronic evidences'storage mediums, such as hard disks.Message digest algorithm is a service or a mechanism to verify the integrity of messages. For judicial forensic applications, it can ensure the originality of messages, which means messages won't been modified, inserted or deleted.MD5 hash algorithm is one of the most popular message digest algorithm. With its high executive efficiency and less operational rounds, MD5 is chosen as the encryption algorithm of our system.This issue discusses how to realize a hard disk with read-only lock based on MD5 message digest algorithm with the FPGA platform. The system can be applied to the judicial electronic forensic field, and be used as a writer blocker device of electronic evidences'storage mediums. USB interface is used to take responsibility for the connection and communication among the system, computers and portable storage mediums. The hard disk with read-only lock we designed can cut off the writing channel in the data transmission interface layer, so that it can protect the electronic evidences not to be modified on the portable storage mediums efficiently. Meanwhile, we realize the MD5 algorithm with a hardware implementation and optimize it, which enhances the message digest's speed and reduces its resource cost. Altera's DE2 development board is selected as the system's FPGA hardware development platform. The top-down design methodology is adopted and system is divided. The structures of how to realize the MD5 algorithm are studied intensively and implemented.An iterative 4-stages pipeline structure is applied and MD5 calculating module is realized. Our design takes use of the ISP1362 USB controller chip and reusable IP core technology to design the interfaces among the system, computers and portable storage mediums respectively.The whole system is designed with the Quartus II software and using Verilog HDL as its programming language. It's simulated with Modelsim SE software.The system's hardware test results show that the system we design can not only protect the electronic evidences correctly and efficiently, but the speed and throughput of the evidences'hash value calculation are faster and bigger. Comparison between our design and the other implementations of MD5 based on FPGA shows that the hard disk with read-only lock calculates faster and executes more, but with less resources utilization.