Design Of Security U Disk And Application In Management Of Files With Multi-Security Levels

After analyzing the security threats of U-disk during its using, aiming at the actuality that problems are remain after security measures being carried out in the host and device respectively, the functions that secure U-disk should contain are made clear. According to the partitioning of hardware and software, the implementation modality and position of the security mechanisms are made sure. On the basis above, secure removable storage system based on USB is designed, which includes secure U-disk and scheme of multilevel security.According to the overall scheme of the system, the hard structure and corresponding firmware of secure U-disk are designed. On the basis of common U-disk, a secure memorizer is added. With taking advantage of the characteristic that a password is needed when accessing to the memorizer, parameters are stored in security, laying the foundations of secure functions such as identity authentication, access control, encryption storage and multilevel security. Firmware of secure U-disk is designed in accordance with hierarchy, and according to its working procedure, secure modules including unlocking secure functions based on particular command and processing secure memorizer are designed. As a result security accessing to secure U-disk and secure parameters is achieved.Aiming at the problem of information leakage while U-disk being used among different secure levels, a scheme of multilevel security based on the secure U-disk described above is proposed. Fine grain access control mechanism is added to file operations, and data is encrypted transparently, trying to solve the problem mentioned above, which used to be overcome through management rather than technology.Finally, a secure U-disk and a scheme of multilevel security are realized, and the designed secure functions are tested according to the working process. The results suggest that the scheme should realize the security storage of data and the security while U-disk using among PCs with different security levels.