关键词: 网络编码，数据备份，文件备份，存储空间，安全保密性

Abstract: According to the problems that data backup needs a lot of storage space and its safe privacy needs to be protected, a file backup scheme based on network coding was proposed. Specifically, adopting network coding, many backup files arc encoded into one encoded file, and then saved in the backup server. This scheme includes the following aspects;the principle of backup, the process of backup, influence of file update on recovery and how to handle it,backup file update and the global control system. Experiment and theoretical analysis show, compared with traditional method, this scheme can save storage space greatly and enhance the safe privacy of the backup data, but decrease appreciably the recoverability of it and increase the complexity of the system.

Key words: Network coding, Data backup, File backup, Storage space, Safe privacy