c#通过DES加密算法加密大文件的方法

using System.Collections;using System.Configuration;using System.Data;using System.Linq;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Xml.Linq;using System.Text;using System.IO;using System.Security.Cryptography;public partial class Default2 : System.Web.UI.Page{  protected void Page_Load(object sender, EventArgs e)  {  }  private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };//自定义密匙  private string filePathA;//储存文件路径  private string filePathB;//储存文件复制后的路径  /// <summary>  /// 文件加密  /// </summary>  /// <param name="inFile">文件储存路径</param>  /// <param name="outFile">储存文件复制的路径</param>  /// <param name="encryptKey"></param>  /// <returns></returns>  public bool EncryptDES(string inFile, string outFile, string encryptKey)  {   byte[] rgb = Keys;   try   {    byte[] rgbKeys = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));    FileStream inFs = new FileStream(inFile, FileMode.Open, FileAccess.Read);//读入流    FileStream outFs = new FileStream(outFile, FileMode.OpenOrCreate, FileAccess.Write);// 等待写入流    outFs.SetLength(0);//帮助读写的变量    byte[] byteIn = new byte[100];//放临时读入的流    long readLen = 0;//读入流的长度    long totalLen = inFs.Length;//读入流的总长度    int everylen=0;//每次读入流的长度    DES des = new DESCryptoServiceProvider();//将inFile加密后放到outFile    CryptoStream encStream = new CryptoStream(outFs, des.CreateEncryptor(rgb, rgbKeys), CryptoStreamMode.Write);    while (readLen < totalLen)    {     everylen = inFs.Read(byteIn, 0, 100);     encStream.Write(byteIn, 0, everylen);     readLen = readLen + everylen;    }    encStream.Close();    inFs.Close();    outFs.Close();    return true;//加密成功   }   catch (Exception ex)   {    Response.Write(ex.Message.ToString());    return false;//加密失败   }  }  public bool DecryptDES(string inFile, string outFile, string encryptKey)  {   byte[] rgb = Keys;   try   {    byte[] rgbKeys = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));    FileStream inFs = new FileStream(inFile, FileMode.Open, FileAccess.Read);//读入流    FileStream outFs = new FileStream(outFile, FileMode.OpenOrCreate, FileAccess.Write);// 等待写入流    outFs.SetLength(0);//帮助读写的变量    byte[] byteIn = new byte[100];//放临时读入的流    long readLen = 0;//读入流的长度    long totalLen = inFs.Length;//读入流的总长度    int everylen=0;//每次读入流的长度    DES des = new DESCryptoServiceProvider();//将inFile加密后放到outFile    CryptoStream encStream = new CryptoStream(outFs, des.CreateDecryptor(rgb, rgbKeys), CryptoStreamMode.Write);    while (readLen < totalLen)    {     everylen = inFs.Read(byteIn, 0, 100);     encStream.Write(byteIn, 0, everylen);     readLen = readLen + everylen;    }    encStream.Close();    inFs.Close();    outFs.Close();    return true;//加密成功   }   catch (Exception ex)   {    Response.Write(ex.Message.ToString());    return false;//加密失败   }  }  /// <summary>  /// 拷贝文件  /// </summary>  public void copyFile()  {   filePathA = this.fei.PostedFile.FileName;//获取文件全部路径   string fileName = this.fei.FileName;   string path = System.IO.Path.GetDirectoryName(filePathA);   filePathB = path + "//1" + fileName;//重新设置文件名   File.Copy(filePathA, filePathB);  }  protected void btnOK_Click(object sender, EventArgs e)  {   copyFile();   if (EncryptDES(filePathB, filePathA, "mingrisoft"))   {    RegisterStartupScript("false", "<script>alert('加密成功!//n');</script>");   }   else   {    RegisterStartupScript("false", "<script>alert('失败成功!//n');</script>");   }   File.Delete(filePathB);  }  protected void btnCancel_Click(object sender, EventArgs e)  {   copyFile();   if (DecryptDES(filePathB, filePathA, "mingrisoft"))   {    RegisterStartupScript("false", "<script>alert('加密成功!//n');</script>");   }   else   {    RegisterStartupScript("false", "<script>alert('失败成功!//n');</script>");   }   File.Delete(filePathB);  }}