File Shredder Code Sample (C# 4.0)

by Ryan Jones on Jul.23, 2011, under Code Snippet

It has been a while since I last posted a code sample. So here is one for you guys to take a look at. Below is the file/directory shredder class.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96

class FileUtilities
{
private static Random Randomizer = new Random();

public static bool Shred(string directoryPath, bool shouldDelete = true)
{
bool success = true;
try
{
string[] files = Directory.GetFiles(directoryPath, "*", SearchOption.AllDirectories);
foreach (string file in files)
{
success &= FileUtilities.ShredFile(file, shouldDelete);
}

string[] directories = Directory.GetDirectories(directoryPath,
"*",
SearchOption.AllDirectories).OrderByDescending(str =>
str.Split('\\').Length - 1).ToArray();
foreach (string directory in directories)
{
success &= FileUtilities.ShredDirectory(directory, shouldDelete);
}

success &= FileUtilities.ShredDirectory(directoryPath, shouldDelete);
}
catch
{
success = false;
}
return success;
}

public static bool ShredDirectory(string directoryPath, bool shouldDelete = true)
{
bool success = true;
try
{
DirectoryInfo directoryInfo = new DirectoryInfo(directoryPath);

string[] directoryBits = directoryPath.Split('\\');
directoryBits[directoryBits.Length - 1] = FileUtilities.RandomName(directoryInfo.Name.Length);

string newDirectoryPath = String.Join("\\", directoryBits);
directoryInfo.MoveTo(newDirectoryPath);

if (shouldDelete)
{
directoryInfo.Delete();
}
}
catch
{
success = false;
}
return success;
}

public static bool ShredFile(string filePath, bool shouldDelete = true)
{
bool success = true;
try
{
FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Write);
for (long i = 0; i < fs.Length; i++)
{
fs.WriteByte((byte)Randomizer.Next(0, 255));
}
fs.Close();

FileInfo fileInfo = new FileInfo(filePath);
fileInfo.MoveTo(fileInfo.DirectoryName + @"\" + FileUtilities.RandomName(fileInfo.Name.Length));

if (shouldDelete)
{
fileInfo.Delete();
}
}
catch
{
success = false;
}
return success;
}

private static string RandomName(int length)
{
string fileNameChars = "abcdefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ~!@¤#$£§%^&()+`={}][;,";
string newFileName = String.Empty;
for (int i = 0; i < length; i++)
{
newFileName += fileNameChars[Randomizer.Next(0, fileNameChars.Length)];
}
return newFileName;
}
}

The usage calls for these functions as as follows:

1
2
3

bool success = FileUtilities.Shred(@"D:\Temp"); // This method will recursively shred a file / folder.
bool success = FileUtilities.ShredDirectory(@"D:\Temp"); // This method will shred the contents of a folder and the root folder.
bool success = FileUtilities.ShredFile(@"D:\Temp\test.txt"); // This method will shred a specified file.

I will not go through the code line-by-line to explain it as I feel most of the code is pretty self-explanatory. However if there are any questions feel free to post a comment.