encrypting and decrypting file in c#

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it's work only for text file can any help me how to do it for all kind of files ex: pdf, word etc
the below code encoding all files but while in decrypting it's decoded to some char

plz help me............

C#

protected void FileUpload(int size,string CntType)
{ 
   conn.Open();
   SqlCommand cmd = new SqlCommand("insert into FileDetails values('" + File1.FileName + "','" + CntType + "','" + size + "','" + DateTime.Now + "')", conn);
   cmd.ExecuteNonQuery();
   cmd = new SqlCommand("select max(FileID) from FileDetails", conn);
   using (SqlDataReader dr = cmd.ExecuteReader())
   if (dr.Read())    
   {
      lstFile.Items.Clear();
      lstFile.Items.Add(" \t Keyword Encryption ----&gt;  ");
      lstFile.Items.Add("----------------------------------------------------");
      string[] str=txtKeyword.Text.Split(',');
      foreach(string word in str)
      {
         string strEncrypt = Homomorphic.DesEncrypt(word.ToLower(), true);
         lstFile.Items.Add(" \t   " + strEncrypt);
         SqlCommand cmdindex = new SqlCommand("insert into Indexing values(" + dr.GetValue(0) + ",'"  + strEncrypt + "')", conn);
         cmdindex.ExecuteNonQuery();
      }
      dr.Close();
      lstFile.Items.Add("------------------------------------------------------------");
   }
}

protected void btnUpload_Click(object sender, System.EventArgs e)
{
   try
      {
	for(int i=0;i&lt;request.files.count;i++)&gt;
	{
	    if(Request.Files[i].FileName.Trim().Length &gt;0) 
	    {
		HttpPostedFile file=Request.Files[i];
   	        if(file!=null && file.FileName.Length&gt;0)
                {
                   string strmsg = string.Empty;
                   byte[] fileData = new byte[file.ContentLength];
                   file.InputStream.Read(fileData, 0, file.ContentLength);
                   strmsg = System.Text.Encoding.UTF8.GetString(fileData); 
                   string ps = Homomorphic.DesEncrypt(strmsg.ToLower(),true); 
                   using (StreamWriter writer = new StreamWriter(Path.Combine(GetCurDir(),                Path.GetFileName(file.FileName)), true))
                    {
                           writer.WriteLine(ps);
                           writer.Flush();
                    }
                    FileUpload(file.ContentLength,file.ContentType);
                    Response.Write("&lt;script language='javascript'&gt;alert('Encrypted & Uploaded !')&lt;/script&gt;");
                    lstFile.Items.Add(" \t File Encryption  ----&gt; ");
                    lstFile.Items.Add("------------------------------------------------------");
                    lstFile.Items.Add(" \t  " + ps);
                }
            }
         }
        BindData();
      }
      catch(Exception ex)
       {
            lblError.Text=ex.Message;
       }
}

Posted 18-May-13 21:39pm

Member 10017812

Updated 18-May-13 23:47pm

tumbledDown2earth

v2

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OriginalGriff 19-May-13 3:49am

If you are going to post code blocks for us to look at, then at least be polite enough to post the formatted code, even if you don't use code blocks or pre tags to preserve the formatting - we can add those if we need to, but I'm not sitting here reformatting your code to be readable!
Use the "Improve question" widget to edit your question and provide better information.

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Amey K Bhatkar · Answer 1 · 2013-05-19T00:20:00

you can read all text from word file and then encrypt/decrypt it.
You can use Microsoft.Office.Interop.Word to read form word
for Excel Mircrosoft.office.Interop.Excel
I will post code to read word file.

C#

Microsoft.Office.Interop.Word.Application word = new Microsoft.Office.Interop.Word.Application();
object miss = System.Reflection.Missing.Value;
object path = @"myDocument.docx";
object readOnly = true;
Microsoft.Office.Interop.Word.Document docs = word.Documents.Open(ref path, ref miss, ref readOnly, ref miss, ref miss, ref miss, ref miss, ref miss, ref miss, ref miss, ref miss, ref miss, ref miss, ref miss, ref miss, ref miss);
string totaltext = "";
for (int i = 0; i < docs.Paragraphs.Count; i++)
{
totaltext += " \r\n " + docs.Paragraphs[i + 1].Range.Text.ToString();
}
Console.WriteLine(totaltext);

charles henington · Answer 2 · 2013-05-19T00:21:00

C#

using System;
using System.IO;
using System.Security.Cryptography;
public static byte[] Encypt(byte[] buffer, byte[] rgbSalt, string password, int iterations, PaddingMode paddingMode, CipherMode cipherMode)
        {
            using (Rijndael encryption = Rijndael.Create())
            {
                encryption.Padding = paddingMode;
                encryption.Mode = cipherMode;
                using (PasswordDeriveBytes passwordbuffer = new PasswordDeriveBytes(password, rgbSalt))
                {
                    encryption.Key = passwordbuffer.GetBytes(32);
                    encryption.IV = passwordbuffer.GetBytes(16);
                    passwordbuffer.IterationCount = iterations;
                    using (MemoryStream memory = new MemoryStream())
                    {
                        using (CryptoStream crypto = new CryptoStream(memory, encryption.CreateEncryptor(), CryptoStreamMode.Write))
                        {
                            crypto.Write(buffer, 0, buffer.Length);
                        }
                        return memory.ToArray();
                    }
                }
            }
        }

encrypting and decrypting file in c#

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