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
/// <summary>
/// 密钥，这个密码可以随便指定
/// </summary>
public static string sSecretKey = "?\a??64(?";
2） 也可以生成密钥
/// <summary>
/// 生成一个64位的密钥
/// </summary>
/// <returns>string</returns>
public static string GenerateKey()
{
//创建对称算法的一个实例。自动生成的密钥和IV。
DESCryptoServiceProvider desCrypto = (DESCryptoServiceProvider)DESCryptoServiceProvider.Create(); // 使用自动生成的密钥进行加密。
return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
}
二、调用ZeroMemory 函数从内存中删除Key
///<summary>
/// 调用该函数从内存中删除的Key后使用
/// </summary>
[DllImport("KERNEL32.DLL", EntryPoint = "RtlZeroMemory")]
public static extern bool ZeroMemory(IntPtr Destination, int Length);
三、加密文件
/// <summary>
/// 加密文件
/// </summary>
/// <param name="sInputFilename">待加密的文件的完整路径</param>
/// <param name="sOutputFilename">加密后的文件的完整路径</param>
public static void EncryptFile(string sInputFilename, string sOutputFilename)
{
FileStream fsInput = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read); FileStream fsEncrypted = new FileStream(sOutputFilename, FileMode.Create, FileAccess.Write);
DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
ICryptoTransform desencrypt = DES.CreateEncryptor();
CryptoStream cryptostream = new CryptoStream(fsEncrypted, desencrypt, CryptoStreamMode.Write); byte[] bytearrayinput = new byte[fsInput.Length];
fsInput.Read(bytearrayinput, , bytearrayinput.Length);
cryptostream.Write(bytearrayinput, , bytearrayinput.Length); cryptostream.Flush();
fsInput.Flush();
fsEncrypted.Flush();
cryptostream.Close();
fsInput.Close();
fsEncrypted.Close();
}
四、解密文件
/// <summary>
/// 解密文件
/// </summary>
/// <param name="sInputFilename">待解密的文件的完整路径</param>
/// <param name="sOutputFilename">解密后的文件的完整路径</param>
public static void DecryptFile(string sInputFilename, string sOutputFilename)
{
DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey); FileStream fsread = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
ICryptoTransform desdecrypt = DES.CreateDecryptor();
CryptoStream cryptostreamDecr = new CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read);
StreamWriter fsDecrypted = new StreamWriter(sOutputFilename);
fsDecrypted.Write(new StreamReader(cryptostreamDecr).ReadToEnd());
fsDecrypted.Flush();
fsDecrypted.Close();
}
五、完整代码
/// <summary>
/// 文件加密
/// </summary>
public class FileSecretHelper
{
/// <summary>
/// 密钥，这个密码可以随便指定
/// </summary>
public static string sSecretKey = "?\a??64(?"; /// <summary>
/// 调用该函数从内存中删除的Key后使用
/// </summary>
[DllImport("KERNEL32.DLL", EntryPoint = "RtlZeroMemory")]
public static extern bool ZeroMemory(IntPtr Destination, int Length); /// <summary>
/// 生成一个64位的密钥
/// </summary>
/// <returns>string</returns>
public static string GenerateKey()
{
//创建对称算法的一个实例。自动生成的密钥和IV。
DESCryptoServiceProvider desCrypto = (DESCryptoServiceProvider)DESCryptoServiceProvider.Create(); // 使用自动生成的密钥进行加密。
return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
} /// <summary>
/// 加密文件
/// </summary>
/// <param name="sInputFilename">待加密的文件的完整路径</param>
/// <param name="sOutputFilename">加密后的文件的完整路径</param>
public static void EncryptFile(string sInputFilename, string sOutputFilename)
{
FileStream fsInput = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read); FileStream fsEncrypted = new FileStream(sOutputFilename, FileMode.Create, FileAccess.Write);
DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
ICryptoTransform desencrypt = DES.CreateEncryptor();
CryptoStream cryptostream = new CryptoStream(fsEncrypted, desencrypt, CryptoStreamMode.Write); byte[] bytearrayinput = new byte[fsInput.Length];
fsInput.Read(bytearrayinput, , bytearrayinput.Length);
cryptostream.Write(bytearrayinput, , bytearrayinput.Length); cryptostream.Flush();
fsInput.Flush();
fsEncrypted.Flush();
cryptostream.Close();
fsInput.Close();
fsEncrypted.Close();
} /// <summary>
/// 解密文件
/// </summary>
/// <param name="sInputFilename">待解密的文件的完整路径</param>
/// <param name="sOutputFilename">解密后的文件的完整路径</param>
public static void DecryptFile(string sInputFilename, string sOutputFilename)
{
DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
DES.Key = ASCIIEncoding.ASCII.GetBytes(sSecretKey);
DES.IV = ASCIIEncoding.ASCII.GetBytes(sSecretKey); FileStream fsread = new FileStream(sInputFilename, FileMode.Open, FileAccess.Read);
ICryptoTransform desdecrypt = DES.CreateDecryptor();
CryptoStream cryptostreamDecr = new CryptoStream(fsread, desdecrypt, CryptoStreamMode.Read);
StreamWriter fsDecrypted = new StreamWriter(sOutputFilename);
fsDecrypted.Write(new StreamReader(cryptostreamDecr).ReadToEnd());
fsDecrypted.Flush();
fsDecrypted.Close();
}
}