On the basis of the analysis of the file system FAT 32 and NTFS, the principle to delete the files is analyzed, and the policy to delete the files in security is proposed.

• 在对FAT 32和NTFS两种文件系统分析的基础上，分析了文件删除的原理，提出了文件安全删除策略，深入研究了安全删除的设计和实现技术。