1 通过,写入零
This option overwrites with binary zeros (0x00).
1 通过,随机数据
This option overwrites with a single pass of random data.
3 通过,删除前擦写 3 次
This option overwrites regular files before deleting them. Files are overwritten three times, first with the byte pattern 0xff, then 0x00, and then 0xff again, before they are deleted.
7 通过,美国国防部标准
This option meets the U.S. Department of Defense DoD 5220.22-M (ECE) standard for securely erasing magnetic media. It erases the information used to access your files and writes over the data seven times (0xF6, 0x00, 0xFF, random data, 0x00, 0xFF, and random data).
35 通过, Peter Gutmann 算法
WARNING:
You should not perform these operations on a solid-state drive or a Fusion Drive because the operations can reduce the lifespan of those drives.
Moreover, because the internal controller can make data reallocations to manage the wear of the blocks, it is difficult to know if previous copies of data do not exist.