The software-based method uses the computer’s CPU to perform encryption/decryption tasks. But this kind of method has some disadvantages: (1) The encryption/decryption software can easily to be monitored by a Trojan program; (2) The instructions meanwhile of the encryption/decryption are executed by the CPU, which will consume more computer resources; (3) It is difficult to transfer the encryption/decryption software among different operating systems. The K210 portable hard disk of Netac Technology Company, NetDisk Mini portable hard disk of Ximeta Company and Truecrypt Foundation use the software encrypted/decryption method [1-4].The hardware-based method uses special chips to accelerate the encryption/decryption process. This method needs less computer resources.

The E906 portable hard-disk of the EAGET company, the P681 portable hard-disk of the Agio company and the Drive trust hard-disk of Seagate company use the hardware encryption/decryption method Inhibitors,Modulators,Libraries [5-7].Usually, the key is stored in special sectors of the hard disk or USB’s flash in both of software-based Inhibitors,Modulators,Libraries and the hardware-based encryption/decryption system. The security of hardware-based hard-disk encryption/decryption is higher than that of the software-based hard-disk encryption/decryption. However, it is still possible that the key can be broken because the key is usually stored in special sectors of the hard-disk or USB’s flash.In this paper, a MEMS coded lock is added in the hardware-based encryption/decryption system. The user’s password is discriminated by the MEMS coded lock, and then the key stored in the MEMS coded lock is transferred into the AES encryption/decryption module.

It is very difficult to break the key from the mechanical maze (two groups of CMGs), thus the security of the hardware-based encryption/decryption system with a MEMS coded lock is greatly increased. The paper is arranged as follows: In Section 2, the framework Inhibitors,Modulators,Libraries of the portable Inhibitors,Modulators,Libraries hard disk encryption/decryption system is described. In Section 3, the design of the USB interface card is introduced. In Section 4, the ATA protocol command decoder module is given. In Section 5, the data hardware encryption/decryption is studied. In Section 6, the controlling circuit of the MEMS coded lock is studied. At last, this paper gives the tested results of the first generation prototype of the portable hard disk encryption/decryption system with MEMS coded lock.

2.?The Frame Work of the Portable Hard Disk GSK-3 Encryption/Decryption System with MEMS Coded Lock2.1. The Structure of the Portable Hard Disk Encryption/Decryption SystemFigure 1 shows the portable hard Axitinib chemical structure disk encryption/decryption system with MEMS coded lock, which is realized by FPGA.Figure 1.The frame work of the portable hard disk encryption/decryption system with MEMS coded lock.