Adaptive Data Wiping Scheme with Adjustable Parameters for Ext4 File System

Data wiping is a useful technology which can prevent possible data recovery in a file system. But the growth of the amount of data usually leads to a decline in wiping efficiency. In order to make improvement, a novel data wiping scheme for Ext4 file system DWSE is proposed. It includes two proposed algorithms for wiping files and free space adaptively. According to a rate of rest blocks which is specified by users, the file wiping algorithm WFile tries to clean part of a selected file for saving time. The free space wiping algorithm WFree tries to speed up the process of cleaning dirty blocks by employing a random sampling and hypothesis testing method with two adjustable rates which represent status and content of a block group. A journal cleaning algorithm CleanJ is also proposed which tries to clean old records by creating and deleting temporary files for preventing data recovery from a journal file. With the help of parameters, users can wipe their data in a balanced way between security and efficiency. Several experiments are performed on our scheme. The experimental results show that our scheme can wipe files and free space in different security and efficiency with different parameters. Our scheme can achieve higher security and efficiency than other two data wiping schemes.