計算檔案的MD5值上傳到伺服器 下載下傳驗證檔案是否被篡改

using System;

using System.Windows.Forms;

using System.Security.Cryptography;

using System.IO;

namespace 計算檔案的MD5

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)

            //建立與伺服器的連接配接

            FtpClient fc = new FtpClient("127.0.0.1","test","123");

            //上傳本地檔案到伺服器命名為02...檔案

            fc.Upload(new FileInfo("textFilePath.Text"), "02" + DateTime.Now.ToString("yyyyMMdd")+".xls");

            //擷取内容的MD5

            string md5 = MD5Value("textFilePath.text");

            //擷取檔案的MD5加上密鑰之後的新的MD5

            string newMD5 = GetMD5(md5+"tianwang");//檔案的MD5加上密鑰

            //流處理，将新的MD5值寫入文本檔案

            File.WriteAllText(@"c:\02" + DateTime.Now.ToString("yyyyMMdd") + ".text",newMD5);

            //上傳文本檔案到遠端伺服器

            fc.Upload(new FileInfo(@"c:\02" + DateTime.Now.ToString("yyyyMMdd") + ".text"), @"c:\02" + DateTime.Now.ToString("yyyyMMdd") + ".text");

        /// <summary>

        /// 計算檔案MD5值

        /// </summary>

        /// <param name="str">需要計算的檔案路徑</param>

        /// <returns>MD5值</returns>

        public static string MD5Value(String filepath)

            MD5 md5 = new MD5CryptoServiceProvider();

            byte[] md5ch;

            using (FileStream fs = File.OpenRead(filepath))

            {

                md5ch = md5.ComputeHash(fs);

            }

            md5.Clear();

            string strMd5 = "";

            for (int i = 0; i < md5ch.Length - 1; i++)

                strMd5 += md5ch[i].ToString("x").PadLeft(2, '0');

            return strMd5;

        /// 計算字元串的MD5

        /// <param name="sDataIn"></param>

        /// <returns></returns>

        public static string GetMD5(string sDataIn)

            MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();

            byte[] bytValue, bytHash;

            bytValue = System.Text.Encoding.UTF8.GetBytes(sDataIn);

            bytHash = md5.ComputeHash(bytValue);

            string sTemp = "";

            for (int i = 0; i < bytHash.Length; i++)

                sTemp += bytHash[i].ToString("X").PadLeft(2, '0');

            return sTemp.ToLower();

        /// 判斷伺服器上的檔案是否被篡改，如果沒有則讀取

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private void button2_Click(object sender, EventArgs e)

            //擷取目前系統時間

            string datestr = DateTime.Now.ToString("yyyyMMdd");

            //将伺服器上個檔案下載下傳下來

            fc.Download("02" + datestr + ".xls", @"c:\02" + datestr + ".xls");

            //計算下載下傳下來的xls檔案的MD5值+密鑰

            string md5 = MD5Value(@"c:\02" + datestr + ".xls");

            string newMD5 = GetMD5(md5 + "tianwang");

            //下載下傳伺服器上的保留的MD5txt檔案MD5的值

            fc.Download("02" + datestr + ".txt", @"c:\t.text");

            string txt = File.ReadAllText(@"c:\t.txt");

            //檢查檔案是否被篡改

            if(txt!=newMD5)

                MessageBox.Show("檔案被篡改");

                return;

            using(FileStream stream=File.OpenRead(@"c:\02.xls"))

                HSSFWorkbook wb = new HSSFWorkbook(stream);

                HSSFSheet sheet = wb.GetSheetAt(0);

                MessageBox.Show(sheet.LastRowNum.ToString());

    }

}