C# 文件夹加密

可以加密文件内容，也可以对文件夹本身进行加密，本文对文件夹加密。

一、指定或生成一个密钥

1）指定的密钥

1  /// <summary>
2         /// 密钥，这个密码可以随便指定
3         /// </summary>
4         public static string sSecretKey = "?\a??64(?";

2） 也可以生成密钥

 1   /// <summary>
 2         /// 生成一个64位的密钥
 3         /// </summary>
 4         /// <returns>string</returns>
 5         public static string GenerateKey()
 6         {
 7             //创建对称算法的一个实例。自动生成的密钥和IV。
 8             DESCryptoServiceProvider desCrypto = (DESCryptoServiceProvider)DESCryptoServiceProvider.Create();
 9
10             // 使用自动生成的密钥进行加密。
11             return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
12         }

二、调用ZeroMemory 函数从内存中删除Key

1  /// <summary>
2         /// 调用该函数从内存中删除的Key后使用
3         /// </summary>
4         [DllImport("KERNEL32.DLL", EntryPoint = "RtlZeroMemory")]
5         public static extern bool ZeroMemory(IntPtr Destination, int Length);

三、加密文件

 1   /// <summary>
 2         /// 加密文件
 3         /// </summary>
 4         /// <param name="sInputFilename">待加密的文件的完整路径</param>
 5         /// <param name="sOutputFilename">加密后的文件的完整路径</param>
 6         public static void EncryptFile(string sInputFilename, string sOutputFilename)
 7         {
 8             FileStream fsInput = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
 9
10             FileStream fsEncrypted = new FileStream(sOutputFilename, FileMode.Create, FileAccess.Write);
11             DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
12             DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
13             DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
14             ICryptoTransform desencrypt = DES.CreateEncryptor();
15             CryptoStream cryptostream = new CryptoStream(fsEncrypted, desencrypt, CryptoStreamMode.Write);
16
17             byte[] bytearrayinput = new byte[fsInput.Length];
18             fsInput.Read(bytearrayinput, 0, bytearrayinput.Length);
19             cryptostream.Write(bytearrayinput, 0, bytearrayinput.Length);
20
21             cryptostream.Flush();
22             fsInput.Flush();
23             fsEncrypted.Flush();
24             cryptostream.Close();
25             fsInput.Close();
26             fsEncrypted.Close();
27         }

四、解密文件

 1 /// <summary>
 2         /// 解密文件
 3         /// </summary>
 4         /// <param name="sInputFilename">待解密的文件的完整路径</param>
 5         /// <param name="sOutputFilename">解密后的文件的完整路径</param>
 6         public static void DecryptFile(string sInputFilename, string sOutputFilename)
 7         {
 8             DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
 9             DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
10             DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
11
12             FileStream fsread = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
13             ICryptoTransform desdecrypt = DES.CreateDecryptor();
14             CryptoStream cryptostreamDecr = new CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read);
15             StreamWriter fsDecrypted = new StreamWriter(sOutputFilename);
16             fsDecrypted.Write(new StreamReader(cryptostreamDecr).ReadToEnd());
17             fsDecrypted.Flush();
18             fsDecrypted.Close();
19         }

五、完整代码

 1 /// <summary>
 2     /// 文件加密
 3     /// </summary>
 4     public class FileSecretHelper
 5     {
 6         /// <summary>
 7         /// 密钥，这个密码可以随便指定
 8         /// </summary>
 9         public static string sSecretKey = "?\a??64(?";
10
11         /// <summary>
12         /// 调用该函数从内存中删除的Key后使用
13         /// </summary>
14         [DllImport("KERNEL32.DLL", EntryPoint = "RtlZeroMemory")]
15         public static extern bool ZeroMemory(IntPtr Destination, int Length);
16
17
18         /// <summary>
19         /// 生成一个64位的密钥
20         /// </summary>
21         /// <returns>string</returns>
22         public static string GenerateKey()
23         {
24             //创建对称算法的一个实例。自动生成的密钥和IV。
25             DESCryptoServiceProvider desCrypto = (DESCryptoServiceProvider)DESCryptoServiceProvider.Create();
26
27             // 使用自动生成的密钥进行加密。
28             return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
29         }
30
31         /// <summary>
32         /// 加密文件
33         /// </summary>
34         /// <param name="sInputFilename">待加密的文件的完整路径</param>
35         /// <param name="sOutputFilename">加密后的文件的完整路径</param>
36         public static void EncryptFile(string sInputFilename, string sOutputFilename)
37         {
38             FileStream fsInput = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
39
40             FileStream fsEncrypted = new FileStream(sOutputFilename, FileMode.Create, FileAccess.Write);
41             DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
42             DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
43             DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
44             ICryptoTransform desencrypt = DES.CreateEncryptor();
45             CryptoStream cryptostream = new CryptoStream(fsEncrypted, desencrypt, CryptoStreamMode.Write);
46
47             byte[] bytearrayinput = new byte[fsInput.Length];
48             fsInput.Read(bytearrayinput, 0, bytearrayinput.Length);
49             cryptostream.Write(bytearrayinput, 0, bytearrayinput.Length);
50
51             cryptostream.Flush();
52             fsInput.Flush();
53             fsEncrypted.Flush();
54             cryptostream.Close();
55             fsInput.Close();
56             fsEncrypted.Close();
57         }
58
59         /// <summary>
60         /// 解密文件
61         /// </summary>
62         /// <param name="sInputFilename">待解密的文件的完整路径</param>
63         /// <param name="sOutputFilename">解密后的文件的完整路径</param>
64         public static void DecryptFile(string sInputFilename, string sOutputFilename)
65         {
66             DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
67             DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
68             DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
69
70             FileStream fsread = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
71             ICryptoTransform desdecrypt = DES.CreateDecryptor();
72             CryptoStream cryptostreamDecr = new CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read);
73             StreamWriter fsDecrypted = new StreamWriter(sOutputFilename);
74             fsDecrypted.Write(new StreamReader(cryptostreamDecr).ReadToEnd());
75             fsDecrypted.Flush();
76             fsDecrypted.Close();
77         }
78     }