回复：卡卡文件粉碎的内部原理
应该是DoD 5220.22-M的标准吧。
根据这个标准的要求是要求对数据区域进行7次覆盖性写入的。这7次的内容如下：
The free disk space is overwritten seven times:
Pass Data
1 A random character, n = [0, 255]
2 A random character, n
3 Complement of previous character, ~n
4 A random character, n
5 A random character, n
6 Complement of previous character, ~n
7 A random character, n
