文件和文件夹加密的问题

//功能描述： 提供加密和解密的方法
******************************************************************/
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;namespace Common
{
/// <summary>
/// 加密和解密
/// </summary>
public sealed class EncryptDecrypt
{
private EncryptDecrypt(){} //默认密钥向量
private static byte[] Keys = {0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF}; /// <summary>
/// 利用MD5对字符串进行加密
/// </summary>
/// <param name="encryptString">待加密的字符串</param>
/// <returns>返回加密后的字符串</returns>
public static string EncryptMD5(string encryptString)
{
MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider();
UTF8Encoding Encode = new UTF8Encoding();
byte[] HashedBytes = md5Hasher.ComputeHash(Encode.GetBytes(encryptString));
return Encode.GetString(HashedBytes);
} /// <summary>
/// DES加密字符串
/// </summary>
/// <param name="encryptString">待加密的字符串</param>
/// <param name="encryptKey">加密密钥,要求为8位</param>
/// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
public static string EncryptDES(string encryptString,string encryptKey)
{
try
{
byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0,8));
byte[] rgbIV = Keys;
byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
MemoryStream mStream = new MemoryStream();
CryptoStream cStream = new CryptoStream(mStream,dCSP.CreateEncryptor(rgbKey,rgbIV),CryptoStreamMode.Write);
cStream.Write(inputByteArray,0,inputByteArray.Length);
cStream.FlushFinalBlock();
return Convert.ToBase64String(mStream.ToArray());
}
catch
{
return encryptString;
}
} /// <summary>
/// DES解密字符串
/// </summary>
/// <param name="decryptString">待解密的字符串</param>
/// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
/// <returns>解密成功返回解密后的字符串，失败返源串</returns>
public static string DecryptDES(string decryptString,string decryptKey)
{
try
{
byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
byte[] rgbIV = Keys;
byte[] inputByteArray = Convert.FromBase64String(decryptString);
DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
MemoryStream mStream = new MemoryStream();
CryptoStream cStream = new CryptoStream(mStream,DCSP.CreateDecryptor(rgbKey,rgbIV),CryptoStreamMode.Write);
cStream.Write(inputByteArray,0,inputByteArray.Length);
cStream.FlushFinalBlock();
return Encoding.UTF8.GetString(mStream.ToArray());
}
catch
{
return decryptString;
}
} /// <summary>
/// DES加密文件
/// </summary>
/// <param name="inFilePath">待加密文件</param>
/// <param name="outFilePath">加密后的文件</param>
/// <param name="encryptKey">加密密钥</param>
/// <returns></returns>
public static bool EncryptDES(string inFilePath,string outFilePath,string encryptKey)
{  
byte[] rgbIV= Keys;
try
{
byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0,8));
//读入的流
FileStream inFs = new FileStream(inFilePath, FileMode.Open, FileAccess.Read);
//待写的流
FileStream outFs = new FileStream(outFilePath, FileMode.OpenOrCreate, FileAccess.Write);
outFs.SetLength(0);
//创建一个变量来帮助读写
byte[] byteIn  = new byte[100]; //临时存放读入的流
long readLen  = 0;              //读入流的长度
long totalLen = inFs.Length;    //总共读入流的长度
int  everyLen;                  //每次读入流动长度
//读入InFs，加密后写入OutFs
DES des = new DESCryptoServiceProvider();          
CryptoStream encStream = new CryptoStream(outFs, des.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write); 
while(readLen < totalLen)
{
everyLen = inFs.Read(byteIn, 0, 100);
encStream.Write(byteIn, 0, everyLen);
readLen = readLen + everyLen; 
}
encStream.Close();  
outFs.Close();
inFs.Close();
return true;//加密成功
}
catch
{
return false;//加密失败 
}
}
/// <summary>
/// DES解密文件
/// </summary>
/// <param name="inFilePath">待解密文件</param>
/// <param name="outFilePath">待加密文件</param>
/// <param name="decryptKey">解密密钥</param>
/// <returns></returns>
public static bool DecryptDES(string inFilePath,string outFilePath,string decryptKey)
{
byte[] rgbIV= Keys;
try
{
byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey.Substring(0,8));
//读入的流
FileStream inFs = new FileStream(inFilePath, FileMode.Open, FileAccess.Read);
//待写的流
FileStream outFs = new FileStream(outFilePath, FileMode.OpenOrCreate, FileAccess.Write);
outFs.SetLength(0);
//创建一个变量来帮助读写
byte[] byteIn  = new byte[100]; //临时存放读入的流
long readLen  = 0;              //读入流的长度
long totalLen = inFs.Length;    //总共读入流的长度
int  everyLen;                  //每次读入流动长度
//读入InFs，解密后写入OutFs
DES des = new DESCryptoServiceProvider();          
CryptoStream encStream = new CryptoStream(outFs, des.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write); 
while(readLen < totalLen)
{
everyLen = inFs.Read(byteIn, 0, 100);
encStream.Write(byteIn, 0, everyLen);
readLen = readLen + everyLen; 
}
encStream.Close();  
outFs.Close();
inFs.Close();
return true;//解密成功
}
catch
{
return false;//解密失败 
}
}
}
}