本文实例讲述了c#通过DES加密算法加密大文件的方法。分享给大家供大家参考。具体实现方法如下：

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); }}

希望本文所述对大家的C#程序设计有所帮助。